BOTTOM SEDIMENTS OF SAGINAW BAY, MICHIGAN Thais [or the Dogma 0! P11. D. MlCHlGAN STATE UMVERSJTY Leonard Eugene Wood 1958 mmmummmnwmm 31293 01102 7624 :8..— <‘> . r -_. “w .d- i This is to certify that the thesis entitled BOTTOM SEDIMENTS 0F SAGINAW BAY, MICHIGAN presented by LEONARD EUGENE WOOD has been accepted towards fulfillment of the requirements for ‘BhL degree in ,. GEO Lmfl \—-\ / 5/./. W DR. B. T. SANDEFUB Major professor Date-W953 0-169 LIBRARY Michigan State University ‘ u.m--' . I m. . ,_ ,_ b-“ A. PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. DATE DUE MTE DUE DATE DUE we WWW.“ BOTTOM SEDIMENTS OF SAGINAW BAY, MICHIGAN by LEONARD EUGENE WOOD AN ABSTRACT Submitted to the School for Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Geology 1958 ABSTRACT Sixty-one bottom samples were taken from Saginaw Bay with a Petersen dredge and an orange-peel samplei. Samples were taken in six predetermined northwest-southeast traverses. Standard mechanical, chemical, and statistical analyses were performed on all samples. Sediments of the bay are predominantly sand. Locally, coarse sand, granules, and pebbles are found close to the shore; fine silt and sand are in the glacial Saginaw River trench and in areas protected from waves and currents. Since the amount of sediment entering the shallow bay is not great, the distribution is directly related to the attributes within the individual grain and the physical environment of the bay.. Median diameter isopleth patterns indicate belts of major currents which enter the bay from the north, flow around Au Sable Point, continue to the west end of the bay, and leave around Pt. aux Barques. Prevailing currents appear to be deflected toward Charity Island in the vicinity of Sand Point, then turn shoreward again near Hat Point. Current patterns are not clear in the center of the west half of the bay. Poor sorting is common in, although not confined to the fine sediments. Extremely poor sorting in the coarse sediments in the southeast corner of the bay is related to ABSTRACT, continued discharge from the Saginaw River. Sorting in Saginaw Bay in general is more a function of currents than depth. The concentration of heavy minerals is closely related to areas of prevailing currents. Heavy mineral percentage is generally 3.0 per cent throughout the bay; in a few localities amounts up to 11.0 per cent are noted. Since the heavy minerals are derived from heterogeneus glacial drift surrounding the bay, there is little distribution according to species. Physical characteristics cause an individual grain to respond to a given hydraulic condition as shown in the distribution of the metallic opaques, amphiboles, and pyroxenes. Where the opaques are abundant the amphiboles and pyroxenes are noticeably lacking. Roundness and sphericity values of grains are only remotely related to the current patterns. If such a relation does exist it is a result of selective sorting due to the ability of the current to move a grain according to shape, and not to the degree of abrasion by current action. the amount of acid solubles in the sediments averages less than 1.0 per cent. Sediments with more than 3.0 per cent acid solubles may be composed of detrital limestone or shell fragments. Acid soluble content of the Saginaw Bay sediment is related to the source of acid soluble materials rather than the selective distribution of these materials by currents. ABSTRACT, continued Organic carbon in the sediments averages less than 1.0 per cent, but amounts up to 7.0 per cent are found locally. Organic carbon, prevelant in the fine sediments, is derived from planktonic material in the bay and humus from the sur— rounding farm land. Total amount of organic carbon in the sediments is more nearly related to depth than any other factor. The distribution and rate of deposition of both organic and inorganic sediments is largely a function of currents. The sediments in Saginaw Bay conform to the current patterns with local exceptions, and they vary with a degree of complexity proportional to the complexity of the surrounding controlling agents. From the study of recent Saginaw Bay sediments one may establish, with qualification, the rules of sedimentary deposition applicable to ancient sediments. BOTTOM SEDIMENTS OF SAGINAW BAY, MICHIGAN by LEONARD EUGENE soon A THESIS Submitted to the School for Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Geology 1958 ACKNOWLEDGMENTS I wish to gratefully acknowledge the Fish and Wildlife Service, U. S. Department of Conservation, Ann Arbor, Michigan, for supplying the bottom samples used in this analysis. Special thanks to Dr. Frank A. Hooper, Dr. Alfred M. Beeton, and Stanford B. Smith for their assistance during the problem. My sincere appreciation to Dr. Bennett T. Sandefur, Dr. James W. Trow, Department of Geology; and Dr. William D. Baten, Department of Statistics, for their assistance with the problem and criticism of the manuscript. Thanks to Dr. Eugene P. Whiteside, Department of Soil Science, for his criticism of the manuscript; and to Dr. Robert 0. Ball, Department of Fisheries and Wildlife, for his gener- ous help during certain phases of the problem. My most sincere appreciation to my wife, Ann, for her aid in compiling the data and typing the manuscripts. ii TABLE OF CONTENTS LIST OF PLATES . . . . LIST OF TABLES . . . . LIST OF FIGURES . . . INTRODUCTION . . . . . Hydrogeography . . Physiography . . . Regional Geology . Glacial History . Drainage . . . . . Sampling . . . . . Sampling Apparatus Scope of Problem . MEGASCOPIC DESCRIPTION LABORATORY PROCEDURES Drying . . . . . . OF SEDIMENTS . Preparation for Sieve Analysis . Sieve Analysis . Pipette Analysis . SIEVE ANALYSIS DATA . O O O O O STATISTICAL AND GRAPHICAL PRESENTATION Cumulative Curve Analysis. . . . . Median Diameter iii Page vi vii viii 13 16 19 2O 20 21 27 27 27 31 31 34 96 96 97 & ix Page Sorting . . . . . . . . . . . . . . . . . . . 97 Skewness . . . . . . . . . . . . . . . . . .1 99 Kurtosis . . . . . . . . . . . . . . . . . . 99 Phi Scale . . . . . . . . . . . . . . . . . . 100 MEDIAN DIAMETER . . . . . . . . . . . . . . . . . 166 Median Diameter and Depth of Water . . . . . 168 Median Diameter and Skewness . . . . . . . . 174 Median Diameter and Currents . . . . . . . . 174 SORTING . . . . . . . . . . . . . . . . . . . . . 180 Sorting and Median Diameter . . . . . . . . . 183 Sorting and Depth of Water . . . . . . . . . 191 Sorting and Skewness . . . . . . . . . . . . 193 Sorting and Currents . . . . . . . . . . . . 193 HEAVY MINERALS . . . . . . . . . . . . . . . . . 195 Heavy Minerals and Median Diameter . . . . . 206 Heavy Minerals and Depth of Water . . . . . . 209 Heavy Minerals and Sorting . . . . . . . . . 211 Heavy Minerals and Skewness . . . . . . . . . 214 Heavy Minerals and Currents . . . . . . . . . 214 Preparation for Identification . . . . . . . 216 Heavy Mineral Grain Count . . . . . . . . . . 217 Heavy Mineral Suites . . . . . . . . . . . . 221 INWNDNESS AND SPHERICITY . . . . . . . . . . . . 238 BOUNDNESS . . . . . . . . . . . . . . . . . . . . 257 Roundness and Depth of Water . . . . . . . . 25? iv Roundness and Median Diameter . . Roundness and Sorting . . . Roundness and Skewness . . SPHERICITY Sphericity and Depth of Water . . Sphericity and Median Diameter . Sphericity and Sorting. . . . Sphericity and Skewness . . Sphericity and Roundness . . . . Conclusions ACID SOLUBLES Acid Solubles Acid Solubles Acid Solubles Acid Solubles Acid Solubles Acid Solubles ORGANIC CARBON . Organic Carbon Organic Carbon Organic Carbon Organic Carbon Organic Carbon and and and and and an (3 and and and and Median Diameter Depth of Water Organic Carbon Sorting Skewness . . Currents . Median Diameter Depth of Water Sorting Skewness Currents SUMMARY AND CONCLUSIONS BIBLIOGRAPHY Page 262 262 265 267 267 269 269 273 276 280 289 289 292 292 292 296 300 303 305 305 305 309 318 PLATES Plate Page 1 Depth of Water Isopleth Map . . . . . . . . 4 2 Sample Locations and Landmarks . . . . . . 5 3 Median Diameter Distribution . . . . . . . 169 4 Sorting Distribution . . . . . . . . . . . 182 5 Heavy Mineral Percentage Distribution . . . 205 6 Average Roundness Distribution . . . . . . 260 7 Average Sphericity Distribution . . . . . . 268 8 Acid Soluble Percentage Distribution . . . 282 9 Organic Carbon Percentage Distribution . . 297 vi Table 1 62 63 124 125 126 127 128 129 130 131 147 148 - 61 - 123 - 146 TABLES Sieve Analysis Data (Samples 1-69) . Percentile Data from Sieve Analysis Cumulative Curves (Samples 1-69) . . Heavy Mineral Percentage Data 0.177 mm { . Heavy Mineral Percentage Data 001.77 mm - 0 Total Heavy Mineral Percentage Data Common Heavy Mineral Suites from the Bay 0 O O O 0 Rare Heavy Mineral Suites from the Bay 0 I O I 0 Common Heavy Mineral Suites from the Rivers . Rare Heavy Mineral Suites from the Rivers . . . Average Roundness and Sphericity Histograms . Average Roundness and Sphericity Data . O O O 0 Acid Soluble and Organic Carbon Percentage Data . . . . vii Page 35-95 101-104 105-165 196-198 199—201 202-204 222-227 228-233 236 237 241-256 258-259 283-285 Figure 10 ll 12 l3 14 15 16 17 18 19 2O 21 22 FIGURES Bay Location with Counties . . . . . . Northwest - Southeast Profiles . . . . . Northwest - Southeast and East - West Profiles . Surface Geology . . . . . . . . . . . Preglacial Rivers . . . . . . . . . River Drainage Basins . . Laboratory Flow Sheet . . . . . Tyler Screen Sizes vs. Wentworth Scale Pipette Time Scale . . . . . . . . . . Median Diameter vs. Depth of Water . . Median Diameter vs. Skewness . . . . . . Median Diameter vs. Sorting . . . . . . Sorting vs. Depth of Water . . . . . . . Sorting vs. Skewness . . . . . . . . . . Heavy Mineral Percentage vs. Median Diameter . Heavy Mineral Percentage vs. Depth of Water . . . Heavy Mineral Percentage vs. Sorting Heavy Mineral Percentage vs. Skewness Statistical Grain Count . Average Roundness vs. Depth of Water . Average Roundness vs. Median Diameter Average Roundness vs. Sorting . . . . . viii Page 11 15 18 28 32 33 173 175 185 192 194 207 210 212 215 220 261 263 264 Figure Page 23 Average Roundness vs. Skewness . . . . . . 266 24 Average Sphericity vs. Depth of Water . . 270 25 Average Sphericity vs. Median Diameter . . 271 26 Average Sphericity vs. Sorting . . . . . . 272 27 Average Sphericity vs. Skewness . . . . . 274 28 Average Sphericity vs. Average Roundness . 275 29 Acid Soluble Percentage vs. Median Diameter . . 286 30 Acid Soluble Percentage vs. Depth of Water . . . 290 31 Acid Soluble Percentage vs. Organic Carbon Percentage . 291 32 Acid Soluble Percentage vs. Sorting . . . 293 33 Acid Soluble Percentage vs. Skewness . . . 294 34 Organic Carbon Percentage vs. Median Diameter . . 302 35 Organic Carbon Percentage vs. Depth of Water . . . 304 36 Organic Carbon Percentage vs. Sorting . . 306 37 Organic Carbon Percentage vs. Skewness . . 307 ix IN TRODUC TI ON Saginaw Bay is an extension of Lake Huron, reaching approximately fifty miles southwestward into Michigan midway on the western shore of Lake Huron. This shallow body of water is bordered by the agricultural counties of Iosco and Arenac on the northwest, Bay on the west, and Tuscola and Huron on the southeast (Fig. 1). Bay City, at the mouth of the Saginaw River, is the only major city on the bay. Smaller fishing and farming communities are scattered along the 160 miles of shoreline. HYDROGEOGRAPHI -- The bay is approximately 50 miles long and 20 to 25 miles wide, narrowing to 13 miles near its mid-line between Sand Point and Point Lookout. 'Charity and Little Charity Islands are in this narrows. A shoal extends from Sand Point nearly 10 miles northeast to these islands. Several islands are in the bay; the most prominent of which is Charity Island. It is approximately one mile wide. A group of islands lie to the southwest of Sand Point, of which North, Stony, and Katechay are the largest. Three islands of lesser size are between Katechay Island and the mouth of the Sebewaing River. Although there are 1,125 square miles of surface area, shallow water limits navigation on the bay. Data compiled l’Ythe Bureau of Commercial Fisheries, Ann Arbor, show that l { _ a [ tigure l. Saginaw Bay and surrounding counties. 57.1 per cent of the bay by volume is 24 feet or less in depth and 34.3 per cent is 12 feet or less. Maximum depth in the western half of the bay is approximately 46 feet. East of Charity Island the water deepens to approximately 126 feet at the bay entrance (P1. 1). Lake Huron Hydrographic Chart No. 52 (1955) was used as a base for sample locations and to determine the depth of water. Marsh areas are extensive along the western shores. Rocky bottom lies beneath a few feet of water on the south— east side of the bay northeast of the Pigeon River near Oak Point. Much the same type of shore that forms the southeast side of the bay east of Sand Point extends eastward from Point Lookout on the north shore. The irregularity of the shoreline is largely a result of deltas and littoral current depositional features built into the bay. Fish Point, Sand Point, and Oak Point on the southeast shore; Point Au Gres, Point Lookout, Tawas Point, and Au Sable Point on the northwest shore are the most promi- nent features (Pl. 2). Numerous depositional features of lesser importance add to the irregular shoreline. The Tawas Point hook nearly encloses a portion of the larger bay area and forms Tawas Bay at Tawas City. The irregularity of the coast plays a prominent role in the course of prevailing current patterns in the bay. Very little change occurs between shore and lake bottom from Bay City eastward to Bay Port. The shore area l Q I Q I ”l ”I L L SAGINAW BAY DEPTH OF WATER ISOPLETH INTERVALZ 5 Feet PLATE 1 96/ R Au Sable . fl .. Au Setter-’1. ,, ‘3 \h I} ' _. a]! Tones Pt. .. UT! ‘1 Towos Boy . 51 O C 9 "r . . .. u ”— u e g ’ 9 a or g /\ '3'. M L coho t 9 He. our Barents . 4'. ‘ II E ’5 \\ 3 CHARITY | s1 , _ :3 V\ m l. . 37 SLAND {I , ‘ \¥ I ‘ .A P ' . Flat Recs Pt. 1 Au Gus Q '- 2‘3’ § 0 Little Charity |_ ’ .— ‘- “if _/"' n 9 / 9 . u 00" Pom ' (4 /‘~—/’ “~ 1) D , \ \ ' e a .' / M 9 T /" u . s, e K—‘\ . O on, I. ‘ ‘ n . 0 . . ”A ° 9 a 0;) use—- \\_ . a 5‘ /" ‘y u ‘ K “choy l Manx“ ° C ;/ 2 PM 1 A. l 1’ u \ ~ 0 11 . I . I. ‘V/‘\(‘“\ - x O . . 2 2 it \ " PM PM "if: -- M 1— o 5 ° 3 e ‘92.. .. , 'a '3 h t Smh “sit a, 0 .1 '04, A?" "5 Thousands of Feet 1 \\ 7x 0 BAY cm! , -‘ \X 5~N . a \ ‘0 .7/ i ‘1‘\ / m e . l s s 0 ‘ 33 fl ’ 33 33 1. m, 1 l I” l l 1 SAGINAW BAY SAMPLE LOCATIONS And LANDMARKS PLATE 2 consists of flat, low-lying sand ridges which rise inland from the shore; and the beaches, such as they are, range from pebbly to sandy. Marsh areas are extensive. Davis (1908) noted that mud from sluggish streams is trapped in the marshes by vegetation and shoreward wave action. The shoreline on the northwest side of the bay is similar to that southeast of Bay City. As far northeast as the Rifle River the coast features range from very low marsh areas to low-lying sand accumulations. Houghton, in his report of 1893, described this area as low with, ”...large portions of the immediate shores composed of marsh.“ Similar obser- vations were made by Cooper (1905). The coast from Sand Point to Point aux Barques is marked by strong relief between shore and bay bottom. The shore from Sand Point to Port Austin is generally sandy, whereas from Port Austin to Point aux Barques it is rocky. The shoreline from Point Au Gres to An Sable Point consists of sanfiy beaches with a few rocky promontories jutting out into the bay. These promontories probably aid in the accumulation of sand along much of the shoreline. The northwest-southeast bay bottom profiles (Figs. 2A, B and 3B) show two distinct channels extending eastward in the bay. The deeper channel approximately parallels the north shore. In the west end of the bay the channel is wider, shallower, and less well defined (Fig. 28). Ihe east-west profile (Fig. 3A) shows two distinct depressions w43 34263 no «3:23 2058 .N 2.3:. HI xooN 20:.«1uoodxu J I'm I m elm. «22.28.. 3%.: 2.38223 35>}: 32 llnl.’ 0 Id. I um .nlan «29.303 3.54» 333223 352:: I.\.\II/ separated by a ridge or shoal across the bay in the vicinity of Charity Island. East of Charity Island the bottom slopes off gradually toward the open end of the bay. At no place is there an abrupt change in the bottom topography, and the gentle slopes should not be a great factor in the distribution of sediments. The narrow channel formed by the glacial Saginaw (Huronian) River extends from Bay City along the north shore to Lake Huron, thus providing a somewhat deeper navigable route in the western half of the bay. Wind prevails from the southwest. During high winds the water has on occasions blown a considerable distance away from the western shore. Data refering to the physical properties of the bay water with regard to temperature, density and seasonal move- ment may be found in the Saginaw Valley Report (1937) and also in a Report of Currents and Water Masses of Lake Huron (1954). EQISIOGRAPHX -- The land immediately surrounding the bay was recently covered by glacial lake Saginaw. It is topographically low with the exception of a few low hills which are remnants of recessional moraines of the Saginaw Lobe and ancient beaches cut by Lake Saginaw. This area, called the Saginaw Lowland, was discussed by Sherzer (1917). The area adjacent to the bay and in the Saginaw Low— land shows little relief above the 580 foot level of Lake waxy» 5...... 08.0. >40 3¢xh 32 II< I 024..»— >t¢50 >40 zuu3huo Hz..— < 20 um¢u>h.¢<=u ca 0* On ON 0. 10 Huron. The Port Huron Moraine rims the west end of Saginaw Bay, reaching altitudes of 860 feet in Tuscola County, and 820 feet near Bentley in Bay County. The Mayville Moraine reaches an altitude of 900 feet in Tuscola County. The underlying bedrock is reflected in these larger physiographic features of the region. Newcombe (1932) noted that areas of thick drift often conform with pre-Pleistocene surface highs; however, extremely thick deposits of drift are known to fill the old drainage channels. Generally there is very little relief in the area surrounding the bay, but a gradual rise in elevation away from the lowlands indicates ancient shorelines and typical near-shore features of the glacial lake which once covered this now fertile, sandy farmland. REGIONAL GEOLQQX'-- There is no evidence of post- Paleozoic deposition in Michigan or the surrounding regions. It is generally accepted that after the Pennsylvania (or Permian) sediments were deposited, uplift exposed the beds and erosion began and continued to glacial time. If the glacial drift were removed, the Mississippian Marshall sandstone and Goldwater shale would be exposed across the bay at its open end. Progressively younger beds in- cluding the Napolean sandstone, Michigan formation, Bayport limestone, the Pennsylvanian Parma sandstone and the Saginaw sandstone would outcrop in concentric bands inland (Pig. 4). The dip of the beds, amounting to a few degrees, is generally "—5117:— 11 Pennsylvmian Upper Saginaw Bayport Michigan Napoleon Mississi ion — pp ' Marshall Goldwater re 4. Distribution of Mississippian and Pennsylvanian beds in the vicinity of Saginaw Bay. 12 toward the center of the state; however, local structures may possess steep dips basinward. As far as one can determine none of these formations are strongly reflected in the bottom topography of the bay. Sediments have been removed by currents locally, and the bare bedrock is subject to wave action. It is not likely that the sediments in the bay were derived in any quantity from the Mississippian and Pennsylvanian beds which are covered by the drift except for a few outcrops along the shoreline, such as Point aux Barques and Point Lookout. The formations found on or below the surface in the general area surrounding the bay are listed below with a brief description of their lithology. They are described on the Geologic Map of the Southern Peninsula of Michigan (Martin, 1936). PENNSYLVANIAN SYSTEM Upper Saginaw formation Lentioular beds of shale, sand— Verne limestone stone, and limestone; coal beds, Lower Saginaw formation seams, and riders. Parma sandstone White, yellow, and gray glisten- ing quartzose sandstone and con- glomerate with small pebbles of white quartz. MISSISSIPPIAN SYSTEM Bayport limestone White, bluish and gray fossil- iferous limestone and dolomite, locally cherty and sandy. Michigan formation Greenish gray to black shales, dark micaceous limestone, and beds of gypsum and anhydrite. 13 Upper Marshall White and gray sandstone. (Napoleon sandstone) Lower Marshall sandstone White, gray, green and red sand- stone locally very micaceous and fossiliferous. "Peanut" conglom- erate in the eastern part of the state. Goldwater shale Blue, gray, and occasionally red plastic shales, locally apple green. Sandstone and sandy shales in the eastern part of the state. GLACIAL HISTOHX -— The glacial history of Central Michigan and the "Thumb" area has been studied extensively for well over 50 years. Thorough work by Mudge (1897), Taylor (1912), Leverette (1939), Bretz (1951, 1952), and others has unravelled many of the details of the Wisconsin glacial stage of which the Saginaw Lobe was a part. This lobe of ice gouged out the basin for Saginaw Bay, influenced the present drainage pattern, and provided the water for the early Lake Saginaw and ultimately for Saginaw Bay. Spencer (1894) described a large pre-glacial river in the Saginaw Lowland which he called the Huronian River. This river flowed eastward until it joined the Laurentian River northeast of the open end of Saginaw Bay. The Laurentian River originated somewhere to the north and flowed through the Lake Huron depression. Mudge (1897) added two smaller tribu- taries to the pre-glacial drainage in the vicinity of Grand Rapids. The northern tributary was called the Gypsum River 14 and the river draining the area to the south was named the Hastings (Fig. 5). Flint (1957) discussed a pronounced lowering of the water level in the Great Lakes following the Nippissing sub- stage of the Wisconsin ice sheet. It is thought that this lowering of the water level again allowed drainage to the east through the Saginaw Bay depression, and that the Saginaw River originated at this time. The Pleistocene glacial drift, ranging in thickness from a few feet to about 500 feet, lies unconformably on the Paleozoic bed rock. The drift is thickest in Lakeview Township of Saginaw County. Lane (1899, 1902, 1905) noted from drill hole data that the drift thickened toward the west in the direction of Grand Rapids instead of to the east as suggested by Spencer and Mudge in their earlier studies. Several other investi- gators in later years named and described many pre-glacial channels cut in the bedrock which suggested drainage away from Saginaw Bay rather than eastward through the pre-glacial depression. The surface distribution of the moraines denotes that the edges of the Saginaw ice sheet of the Wisconsin glacier were markedly lobate, and it is generally thought that the pre-glacial drainage roughly parallels the south- westerly ice movement from Saginaw Bay. Much of the bed rock and pre-Wisconsin drift in the bay area was eroded by the Saginaw Lobe. LAKE 15 \\ \ \‘ ‘o \4419, I ‘Vflt <>\%; V e e\ e «. 0 * oi" dls‘ fl. ). $9 ‘ “y SAGINAW R- ( yet a .__. A. ___. I ‘4' GRAND R {'2 , ,8 ' % THORNAPPLE R. _ ..... —. _ PREGLAOIAL RIVERS V PRESENT swans Present drainage correlative to supposed pre-glacial drainage (after Mudge, 1897). Figure 5. 16 Several authors support the theory that the underlying bedrock played a great part in directing the Saginaw ice move- ment. von Engeln (1942) observed that the portion of the Saginaw Lobe which occupied topographically low areas moved farther than those portions moving on higher bedrock areas. Leverette and Taylor (1915) noted a distinct relation between the Marshall sandstone and the orientation of the Saginaw Lobe. The ice movement adjusted to the resistant, topograph- ically high sandstone. Kelly (1930) also mentioned the irregularity of the bedrock in the Saginaw Lowland. He pointed out that the country is low and flat, surrounded by a rim of higher land that conforms to the buried escarpment of sandstone and limestone of the Mississippian system. The surface map of Michigan (1956) supports these concepts. DRAINAGE —- Cooper (1905) described the Saginaw Lowland as an area of numerous large swamps and marshes. Although today (inland from the shore) the land is generally free of marshes and swamps, the slow moving streams and numerous drainage ditches imply that the drainage in this low country is still poor. The Saginaw Lowland is drained by sluggish streams forming somewhat of a dendritic drainage pattern. The Saginaw is the largest river discharging into the bay. Its tribu- taries include such major streams as the Cass River, which drains the central "Thumb" area, and the Cheboyganing Shiawassee, Flint, and Tittabawassee Rivers which drain the 17 area toward the center of the state. The Kawkawlin, Pin- conning, Pine, Rifle, Au Gres, and Au Sable Rivers drain the counties bordering the bay on the northwest.- Although the Au Sable River empties into Lake Huron several miles north of the open end of the bay, currents entering the bay un- doubtedly transport sediment for ultimate deposition in Saginaw Bay. Figure 6 shows the major drainage areas contributing to Saginaw Bay as compiled by the Water Resources Commission (1956). Five of the areas shown do not have important rivers draining them, and during the summer many of the streams are reduced to practically no flow. The entire area surrounding Saginaw Bay is very-low and it is not likely that much sediment is contributed to the Bay. An exception to this may take place when the rivers are in flood stage. Ap- proximately 8,375 square miles of land is drained into the 1,125 square miles of Saginaw Bay. Since the gradients of the rivers entering the bay are generally low, many of the sfleams have built deltas and bars across their mouths. These features stem largely from a lack of power to carry the sediments out into the currents Rhodehamel (1951) reports that the gradient of the Saginaw River is so low that often water from the bay backs several miles upstream when the wind blows from the northeast. It is for this reason that stream-flow data is difficult to obtain when streams are flowing under normal conditions. 18 RIVER BASINS I. TAWAS R. Z.AU$A8LE R. 3.RIFLE R. 4. PINE R. 5.KAWKAWLIN R. DRAINAGE BASIN OUTLINES PREPARED BY WATER RESOURCES COMM. ISSS Figure 6. Drainage basins contributing to Saginaw Bay. 19 SAMPLING -- The 61 samples used in this investigation were collected by the U. S. Department of Conservation during two summer cruises in 1956, followed by supplementary cruises, one in October 1957, in the vicinity of Bay City, and one in November 1957, off the shores of Au Sable Point and Point aux Barques. The vessels used for sampling included Michigan Department of Conservation Patrol boats and the Fish and Wildlife Research Vessel 9;;22. Sample locations are shown on plate 1. Samples were taken along six northwest traverses which trend perpendicular to the long axis of the bay. The locations of Samples 1 to 53 were chosen to provide synoptic data on the physical and chemical conditions in Saginaw Bay and not with a sedimentary analysis in mind. Distance between the samples along the northwest traverses range from three- quarters of a mile to one mile in the western half of the bay to as much as five and one-half miles near the open end. Distance between the traverses range from five to nine miles. Three samples off Point aux Barques on the southeast shore and three samples off Au Sable Point on the northwest share were taken in an effort to trace current patterns and sediment movement entering and leaving the bay. No samples were recovered from locations 4, 44, 48, 57, 58, and 60. It is assumed that at those locations either there was no sediment on the bottom or that the material was too coarse to be picked up by the sampler. 20 SAMPLING APPARATUS —— The Petersen dredge was used almost exclusively in the sampling with consistent results. However, during the later cruises in 1957, the orange-peel dredge with a canvas apron was most effective, particularly in the coarse materials. Samples were put in pint jars in their original state. A small amount of formadal in each jar preserved organisms in the sediments in the event that a study of such bottom life might be desired. Six cores were taken, the longest of which was six inches. The study of these cores is not included in this report. SCOPE OF PROBLEM -- The purpose of the problem is to analyze the bottom sediments mechanically, statistically, and in part chemically to correlate such data obtained with the physical environments present in the bay at the time of sampling. MEGASCOPIC DESCRIPTION OF SEDIMENTS The sediments range from coarse materials consisting of large pebbles or cobbles, fossil corals, and shell frag- ments from the areas of strong current and wave action; to medium to fine, clear quartz sand found throughout the bay; to fine, gray silt or clay from deep and quiet water. Coarse, medium, and fine size relationships are based on Wentworth's scale. Coarse: greater than 0.500 mm, medium to fine: between 0.500 and 0.062 mm, and fine: less than 0.062 mm. Since color properties vary greatly in a sediment when it is wet, the following megascopic descriptions of the 61 bottom samples were made after drying. SAMPLE NUMBER DESCRIPTION 1. Medium, predominantly quartz,‘buff sand containing large amounts of rock granules, fossil corals, and shell fragments. 2. Medium, buff sand and a variety of coarse to small granules, fossil corals, and shell chips. 3. Coarse, buff sand, large pebbles, small rock fragments, fossil coralsI and shells. 4. No Sample 5. Fine, light buff quartz sand including a small quantity of rock fragments and fine shell chips. 21 SAMPLE NUMBER 6. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 22 DESCRIPTION Very fine, buff to nearly white quartz sand. Very fine, buff to gray silt con- taining shell chips and bits of organic material. Medium, light buff quartz sand and small shell and rock fragments. Medium, buff quartz sand including some small rock fragments and small pieces of shells. Medium, buff sand, small rock granules,. and numerous shell fragments. Medium, light buff sand including a few rock fragments, granules, and shell chips. Fine, buff sand and a few small rock and shell fragments. Fine to medium, buff quartz sand including rook fragments, granules, and shell fragments. Very fine, buff silt including some sand, rock granules, and fossil corals. Fine, buff quartz sand containing only a few shell chips. Very fine, buff to gray silt con- taining small flakes of mica and shell fragments. Fine, buff to gray sand and silt, small rock fragments and shell chips. Medium, buff sand and a variety of granules, rock fragments and shell chips. Fine to medium, light buff quartz sand containing numerous granules and broken shell fragments. SAMPLE NUMBER 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 23 DESCRIPTION Medium, buff sand, numerous rock granules and small rock fragments. Medium,buff sand and small rock fragments. Fine, light buff quartz sand, small rock fragments.and pebbles. Fine to medium, light buff quartz sand and small rock fragments. Medium, light buff to nearly white quartz sand and small rock fragments. Medium sand, some silt, and small rock fragments. Fine, gray to buff silt and a dmall quantity of sand. Fine to medium, light buff sand, a great variety of granules and pebbles, and a few shell flakes. Medium, buff quartz sand and a quantity of rock fragments, fossil corals, anc shell fragments. Medium, buff sand and a quantity of rock fragments and granules. Fine, buff sand to silt and a few shell fragments. Fine, light buff quartz sand and a few small rock fragments. Fine, buff sand, small rock and shell fragments. Fine, light buff quartz sand con— taining numerous shell fragments. Fine, light buff quartz sand con- taining numerous shell and rock fragments. SAMPLE NUMBER 36. 37. 38. 39. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 24 DESCRIPTION Medium, buff quartz sand, small shells, rock fragments, and granules. Fine, light buff quartz sand, rock fragments and granules. Fine to medium, buff to gray sand and silt, rock fragments and granules. Fine to medium, buff to gray sand and small rock fragments. Very fine, buff sand to silt. Fine, buff sand to silt, some small rock fragments and shell chips. Fine, light buff quartz sand, small rock fragments and shell chips. No Sample. Fine, reddish buff quartz sand and a few small rocks and shell frag- monts. Fine, light buff sand and a few small rock fragments. Fine, buff sand, small rock granules, shells, and shell fragments. No Sample. Coarse, reddish to buff sand and gravel. The sand is predominantly quartz. The coarse material is a variety of rock fragments. Very fine, buff to gray sand and silt and a few small rock fragments. Fine, buff sand to gray silt and a few small rock fragments. Fine, light buff to nearly white quartz sand. SAMPLE NUMBER 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66, 67. 68. 25 DESCRIPTION Fine to medium, light buff to nearly white quartz sand and fine shell fragments. Medium, buff sand, large grabules, ’ shells, and shell fragments. Medium, buff sand, large granules, shells, and shell fragments. Fine to medium, buff sand to silt and small rock and shell fragments. No Sample. No Sample. Fine, light buff quartz sand and very fine shell fragments. No Sample. Fine to medium, light buff quartz sand, small rock and shell frag- ments. Very fine, gray to buff sand and silt. Fine to medium, light buff sand, shell fragments and organic material. Fine to medium, buff quartz sand. Fine, light buff quartz sand, small shell fragments, and bits of organic material. Fine, light buff quartz sand and small shell fragments. Fine to medium, light buff sand, bits of shell fragments, and organic matter. Fine to medium, light buff sand, bits of shell fragments, and organic matter. 26 SAMPLE NUMBER DESCRIPTION 69. Very fine, light buff quartz sand and bits of organic material. LABORATORY PROCEDURES Figure 7 is a flow sheet of laboratory procedures followed in the analysis of the Saginaw Bay sediments. The procedures describing each analysis will be outlined in the discussion of that analysis. DRYING -- Each sample was washed into a pan and allowed to dry in a hood at room temperature. The clayey sediments dried into hard layers and additional treatment to disaggregate was necessary before sieving. PREPARAIIQN FOR SIEVE ANALYSIS -— After drying, each sample was split with the aid of a Jones sample splitter and a micro-splitter. Half of the original sample was saved for dry sieve analysis and the remainder for acid soluble, organic carbon, and heavy mineral analysis. In some instances the original sample was too small for the amount pre-determined for sieve analysis, so only the smallest amount necessary for the other determinations was removed. The remaining sediment was then sieved. Depending on their source, sediments may often contain a great variety of organic and inorganic materials ranging from all forms of vegetation to glass, metallic fragments, and shells. Care was taken during sampling not to choose sites too near designated dumping grounds (Lake Huron Chart No. 52). Saginaw Bay, for the most part, is free of weeds 27 28 >50waaw mwmzozaom .mzzz #103 m_m>._>O.._.._ >mOHm:o 5:43:28 _ 3.23% g 1 3.533 904 _ m a. a a 1 75:33 .2”.sz >>m.mL r J. zo_._.<6mmoomum Scam m2¢n5<flboamHm 25mm mzonaaum =5am 525~55q55a<5 aaHazacmam aao.c ac~.o can.o cum.o mav.c mou.¢ #Hm.o am~.o cv~.o an~.o mn¢.¢ hmo.o wN~.o aah.o cou.o 55 m5a hnN.H nmm.u va.H N¢¢.N Vun.m ©n¢.~ Nee.m mhm.~ Gov.“ wN¢.H omm.N HNN.H N¢m.u nvh.a H~¢.~ om menswenoo m¢m.o mum.c mnu.c mcc.c c~m.c on~.o cbc.o oVH.c ch.o wmu.o c~o.o ohm.o Hou.o o~u.o cvm.c 552.5 55m umm.o wvm.o ch~.o who.o mom.o ¢>~.o aha.c on~.a vmm.o n~m.¢ ouc.o nam.c ONH.O NNH.O O©N.o NuN.c «mm .55 05539 o¢m.o OVm.c onm.c «90.9 mvn.c num.c cow.c nuw.c cum.o nam.c cwo.o onm.c own.c vv~.c cam.¢ Nam.c v: anv.o c~v.o ccm.c can.o can.m wcm.¢ aum.c nam.c O¢V.o cmv.o a-.o cv¢.o ONN.o ooc.m «55.5 52m oc¢.o va.o cmwoc uwm.o coo.” c~¢.o ocm.c cvm.c man.c coo.c mmH.o con.c nhm.o ooo.o~ 555.5 555 an an an am am pm om aw av NV av an mm mm an an .02 104 www.c hom.o cwm.o hvm.c vvm.o wom.o mem.¢ cwm.c Nvm.o amm.o mmm.o th.o opm.c GUM coc.o oco.c ch.¢l mwo.o1 HNO.OI «mo.o1 one.OI ooo.o -o.o u-.o Acn.o avooo omo.¢! am meg oco.~ coo.~ c~o.o wVQ.c Nno.¢ aka.c woa.o coc.~ ouo.c mam." ~om.~ canon Nam.o 3m who.o om~.c -~.o Nv~.c b-.c Nun.o ¢m~.o o-.o mm~.c 4c~.o a~m.o cub.o mau.c om 55a 55555424 m>mnm 2555 525~aw«% ho~kfi C l ) ‘\ .ii‘i' e fl ‘ O 1 01 0 0 .5232: 2.3.313. $35.. .3 “52.3.3 22.2.3539 $0 ounce . 3 9 .v . 9 L .V n.» e sly. 0 \r O O O V CT: 31 D It) (eagiwlnmng) efiniuooms 3 o oo~ uovofldun A.alv noumm obumm uo~hh O 0 O 0 o o O I 0‘ 0 I. 8 8 .7 9 . no my W..T manamofi I Q 0 0 .0 Au .0 0 . 0 .T; «a: «aw «om f 7 0 1 \W m. 2232 £95 25:; $3: $5 .3 58323923 no sands O O N H O N o o o o u: v (eagzvtnuno) ofitgnaoaod O p cm ca can acaoidma A.llv nouum ebowm hauhh 108 .o .o r .a .c r .9 q. .z .9 .... .9 w ”.30 T... Q. 0 0 0 0 0 0 u o _ \\ . «on... "an M 3m. . . _ \ u a: a La _. cum 0 o n9 a? a .5 w h _ on. _ m _ 3 x m U \ can. \ .. 9 \ 31‘ K a \ om \\ 3 \\ 2: a .2232 025% 25$: 33.25. “Sam .3 3:59 535359 so omnda 109 umeoaawo A.aav noumm o>owm “cake . . . . t. 8 8 9 1.8 3 8 9 Q. . W. 9 . 6 0 o I o o o o O 0 0 0 0 ) 039$UBOJOJ (aagmutnmno poa.o ” m o_ owe.” "aw om ¢o«.~ “cm on av on ow or om ca sea a uéaaaz omnadm mazuam: muqumHm mo m>mau m>~smHm mo m>m=o m>~amHm mo m>m=o m>~smHm 7v 8 .799!“an mo "gazo m>§3 22:9 a o N H Sumuaoaag O CO 0 c: q to '0 V‘ (aAgawtnmno) a O r. on co ooa 11.3.~ uwpoadwa A.EEV moswm.o>omm umaha . . . . . . I 3 8. b 9 nu.LooB 90 0 I 8 00 .V C.— o o o o o o o o o I Q 0 0 0- Au 0 .U 0 Au 0 0 ml “ 1 11 «cape "an _ ‘\\\\\\Lu1w _ Y\ Nbfl.~ «mm A O o _ \ POO H .Ow b \ _ x . \ _ _ If. \ \\ 11\§\ ,TIII an honfiflz camadm mazoamz mHmaqmHm mo m>aao m>~s \IIII... 4 Gen." ucm \\ K -qb--dh——-4—-‘p-‘-d ’\ \ an uoaauz uaaadm Nu mszuuu: maqumHm ac m>mau m>~smum mo m>mao m>HsmHm vp onnda ho W>mau Q>HBmHm he M>mao w>Hame he m>m=u Q>HEHBmao m>Hs o c: c '0 V 0‘) N H (aAyzuInuno) ofluauaoJod O CO O ‘— om ca can mu hanauz camadw mamunmz mumwamHm mu canoe he M>m=o M>HEmHm mo m>m=u u>~s mumw4mHm mo.m>u:u m>~amfim no m>m=o a>usmHm mo M>m=o M>HBflnw ho fl>flao fl>HB m~magmHm mo m>m=u m>~a<4=z=u no wands 128 hopoadwa A.fllv nouuw obuum Houha .o .o .1 .z .e w... m. .z w. .... .5913. llll-ill‘ll‘. a+~.o "an T;\\\. -m.~ «am am¢.~ “am _ _ x:\ on uoaauz oaanam mamummz mumaamum me m>m=o m>HamHm he fi>¢ao m>H9MHm ho m>mno H>H9omn uc~ha 0 7n 0 O O 00 .7 0 0 o 0.4 0 T. C 0 .V0. 9 o L 8 o mazummz mequzd m>mHm mo m>=Do m>H9omm Hague O o o O I a 8 '7 9 9 IL 8 8 c7 9 o o o o o 0 0 0 0 0 mazaumz mew4mmw mo.m>dao m>H9oam houhs ”u .o .I .a .e V .9 w. . .z w. “v .9. .9 .130 I 9 p 0 0 o o 0 0 0 _ 1.1. iii} . \\\\\ . _ - , 93.3 «mm . .\ one; :5 n W . v34 3m _ dd hmnauz aggldm wamchk mewflmnm mo m>mao N>Hsdqazau da Quads O .1 <3 0 60 N ) ofluzuooxod c c: a V' (aquvtuuno O Q Q 1‘. cm ca Goa 134 uoeoldma «July conun crown henna V .0 .I .z V. V .9 .t. .z w. W .9 “9.1.0..”5 kW: .3 0 0 o 0 o o . J _ . _ 5 - v3.3 "5— _ _ . ax; 3» mm — -\ w «a hopauz annadm memenfl3 mo omnna mHmHAflmm ho M>mDo M>HE 0 a a: ,3 ) aflvauooaod o c: o o I: v (OAI191nan O r~ an ac aou .1 .- “ 135 uoaofidwn A.lav uoawm obmmm Hoaha .o m. r . .z .9 w .9 n. ... .0. 9...”... I Q 0 0 0 .U 0 0 .0 0 ml 3»... "an \ coc.« "am . «3.— 3m .N _ an .8352 3.355 2:sz $2.25. $65 .2 8:53 532.3323 ma Quads O o N H O CO 3 c: o o u: v (0A319tnmno) ofiuzuaoxad O p cm ca cow 136 ucaoaama A.aav nouwm obomw homha . . o . . . o I 2. 8 .7 n: 9 L.UB._ w MW 10.. M M M w 00 o o 00 o o o o o _ VIJIJI1 ii} _ \ can... .3 u oac.n «am " :4...“ 3m _ \ fl —\ h ‘3 v» umnsuz admadw mb=uum3 mHmMAmHm ho m>z=u m>Hs¢«m acqha 137 m. .o .1 .1 .9 r .9 , "1 .z w. w .9 .92.”. I. .u- 0 o 0 0 0 o T 1. i? a _ \\ 3a.... a _ .. 3% I .3... 3m . . r cum _ 1 S»; 99m h 39 _\ 9, 3m _ m. 9 8n. A 9 \ 8:1 \ S. \ om _ 8 2: an uopaaz odaaam mamoamz mHmaam~m no m>mao m>~smHm ho m>m=o Q>H9mmm mo m>dsu Q>HBmHm mo unadh he fi>fl=o w>Hsme mo m>mau m>~9m~m mo m>mao m>33433233 cad awash O O N n1 c 0‘) o :3 c o a: v (0quutnun9) ofiuguaozad O p. cm ca cod 143 uovofidwn A.iav ocuww obowm uo~ha .m .m. m “Sky _ vxxx ena.o “a: m age.“ “am _ . . w~¢.~ 99m _ N¢ honasz unmadm wamuumz mumwaMHm he H>mbo M>HBmao Q>HB¢ADZDO mofi oaada O O N H O G) 3 <3 3 o u: v (9A1191nmno) ofinzueoaeg O 1* cm ca cow 145 hovoldua A.llv nuuwm abouw houhh no no .I .3 .8 V .9 .t .z w. “7 1.9.1.3.. .l. 3.! 0 0 o 0 0 o d . _ _ . \ ona.¢ «a: u . coo.” «am _ _ 3.34 «am _\ q _ K \\ av hoaaflz camadm wamummz mumwamao m>HBmwm uo~%& O O O o o o O I a 8 .v Q 9 L QL. 1h". 0 n“ I 00 8 LV 0.- o o o o o o o o o I Q 0 0 0 AU 0 0 W 0 AU nu O u-Onu \ T _ ~ _ x o o 1111—...1- .111. - -L I1 1.11 11" irl-l.l 1%. .11 11+.-.IILT 1. 4.. .4- - ”1...... S.- c . 5 _ 1l11..l§1.1 Ill... mp5 .0 u £0 11111111.“..- 1 -- - L 11;-.. L 1 1 1147.4. 1..- -.l..|. 1.1 .1 1L11|..+-1-.1 1. #11:? NOOoN «ow _ 1.| 11-4 -1 -I11-1.1 O- A III .11- Lf.’ Fl '14.... T1- - -1-.. 1 - .1 11------ - ..... 1-1T- 6 A. 1 .1..l.'.| 1 III- 1| 1. 13.11.... III.- -.1,1+fl--o-’.+ >11L1. 11%| 1 -----l.1.1Tl .1. -1T 1.1 1.1!. 1 11. 1.1111. 1+. III. .I l I -.|..|1T1- - 1 .1 - it." +1 - 1r - TI! '1. III; l-..-|Lf.-.I..+ li$1|1¢1 ov hmnazz maasdm mazummz mmqume mo m>¢ao m>HB o c: o If) ‘3' GE. OJ '4 (9A3191nmn3) aBuzuaoan O to O h om co OOH 147 uoaofldwa A.llv uouum o>o«m uouhh . I go o. 9 .u 9 L.unv g o o o 0.0... W141i..- .o .o r .z .e r .l .u. 0 0 0 0 2a.... 2.: \ «3... 3m 23.." 2m. \‘fl ———..-———-—-.—.—.4 ht honanz ouaadm msmumm3 mHmHAMHm mo H>¢=o Q>HE o c: o '0 Q' :0 N H (oquvtnmno) oflvgnaoxod O O O I" 3 3 ecu I48 m¢n.o « a hav.~ «am v-.a «om av nonauz oumadm uoaoldwa Aollv nouwm obowm hauhu .1 .z.er.9- .1 wwwwwumm. 0 0 000 0 a can“ a u can 1. h. one m cw m T. 9 on...” A O oot\ as on ca ooa .mamuuma muqum~m mo m>m=o a>aamHm ma M>d=u m>H9mmm um~ha W. .W P. 8 .V “V .V w; ”6 ma W._W www.mfio I Cu 0 0 0 o 0 0 0 0 0 1- HHflHIIIIJNIIILNIIJIIhWIflIfiVfiAN _ -_ \ mam.c “ a _ \- p»a.c «am _ \\ _ ~mm.~ «cm _ -F \ \\‘ 4‘g‘ an hunaaz «Hmadm m&:oH33 mmwwame ho m>zau m>Hs c c: o :0 IO fl' co N H (8A11utnmno) 3391ua0J8d O p. cm oa oo~ 151 novofidwa A.iav nouwm o>owm Hoaha . . . . . . 1. 3 3 .V n3 9 L.8cu 0 0 fl 8 00 .7 o o o o o o o o a 2m... “.3. \ waa.o ”aw mn~.u «cm f?‘~m———4___=¥;:L:_ -‘r'- __._- an aunauz camadm manuamz mamwam~w mo m>m=o m>He o c: n v- m o: (equutnuno) afinzuaOJad O ‘0 O r. ow ca oou umaoaafia A.Eav nouww o>mmm awake o o o o I 3 8 8 8 .Ve. . “79.9.1516 0 0 TL 0 0 0 O 0 0 <3 0 c> c c: o to n \ v co 0) H (aAggnInmna) afinguaoaad O l‘ om ca cod 3 2.232 395;. 2.5:; 33:24 863 .8 6&3 52.3223 oau vague uoaofldwa A.inv nouum aboum nouha o o .1 .3 .er... .1 .- ewwwuw... 0 0 000 0 o _ S.» a u a 3rd 1 «8.: 3m a cum .2; :5 h 3.. ) M S. m .l v a 8...... 5 A 1.. O O O O p cm ca can in hopauz ogaadm mhmummz wmmwamnm mo N>flao m>~a<492=u Hun wanna 154 hN¢.o u a can.» "am ooh.¢ «am an hmaasz oumadm o I O umwoadma A.EEV momma obowm HoAAB 7o 0 o o O I .6 on f 9 L 8 .7 Q. o o o o .0- o o 0 0 0 0 ma=uH22 mHqumHm mo m>m=o m>Hs 0 v (aquvtnmno O CD 0 t- on oo can uowofldma A.IIV nouwm obowm hours 155 .o .o ...- .z w w W.- m .3 “..- w .93.}. .l a. 0 0 0 0 . _ wIIILwIIJIILWH%HmWM£N#o _ 1....le \ '0 . uwm \J ea man 0 _ \\i\ u ~o«.~ «am _ \\ u . \- om“- aon.~ “cm “ .\\\ .h _ ems _ \N m n cv _ m I 9 \\ can” A 9 \\ oclx -\\ an em \N. ca 1 oo~ \K an uoaaaz efiaadm mamwamz mewamHm mo m>m=o m>~smHm ac m>m=o m>~amHm ho m>mau m>Hsomm uouha \, . .o r .z N... r .9 .t .z w. "v 9.91%... m .9 0 0 0 .u 0. 0 . 0 . _ _ atteumu _ .\ c3436 _ . _ \ . 2&7; _ \ . h . \\ no hananz canadm mamuum3 mHqudzd mbmmm cad wands mo m>m=o m>uemHm mo m>xao m>Hemum ho H>mao Q>HB c c: c 0 I0 v ('3 N o-n (oquutnmno) ofivguaozod O r. om ca oou 161 hmpoadwa A.EEV nonww o>mwn uwdhe O O C O O O O . I z. 8 .V 9L86 H; O I 70 8 u? g o 0 o o .030 a on 0 0 0 0 0 O o O '4 O N C; 1.3 O v CD I!) (any1w1nmn3) afiuuuooJad O to ow om ea ------ - - cod mo m>xau m>HHmHm aaa «Haas uavofidwn A.Iav nouum obowm hoaha 162 .0 .o r .z w. .9 .9 .I .z n... .9 .9 .9 .Lmao I Q 0 0 0 .u 0 0 .U 0 m Tijpj o _ 5»... «ma _ 3.... _ u 1 3a; 3m _\ a... _ an... _ m. _ ova m. .1 9 \ 3...... A 8 w 3( S. \ om \ 3 -- 2: cc 9.3592 camaam mszcam3 mHmwgmHm mo m>x=o m>Heme.mo m>m=u m>~afl=u m>HadaDZDu 165 umuoadfia A.Iav nonwm o>owm uo~ha . . . . . . . 1. Z 9 .V n3 9 L.Bnu o o 1 w. m. w w w . . .o .o . ww. T. 9 0 1"] ijj . .l _ NJIJJJ VJ m _ 9 WM” _ So; :5 _- _ H003" «0m — _ . c: o o c: o D 9‘ m a: rd (aAg1wtnmn3) 3391ueoxad O to O [V om ca ooa MEDIAN DIAMETER Median diameter is defined as the intersection of the 50 per cent line and the cumulative curve. This inter- section splits the sediment into two fractions, 50 per cent finer than the median and 50 per cent coarser. It is commonly recognized that grain size is one of the factors which controls sediment movement, dependent at least in part.on current velocity, depth of water, shape, and density of the particle. The median diameter, therefore, often shows some characteristic relation to any one or all of the variables governing sediment movement. Very little is known of the relationship between median diameter and current velocity owing to the sparcity of bottom current data. It is known that the current velocity at depth usually differs greatly from surface currents, and these currents at depth vary greatly in themselves from one locality to another. Bottom currents range from more than a meter per second to less than a centimeter per second and often are very difficult to record with accuracy (Kennen, 1950). laboratory data shows that several factors influence the movement of sand particles. Menard (1950) found that turbulence, depth of water, density, shape and sorting of the particles influence the relation between grain size and mean current velocity. In shallow water experiments, it was 166 167 found that sand grains can be moved by a slower current if the bed is rippled rather than smooth. This agrees with experiments by Inman (1949) who discovered that fine material often tends to produce a smooth surface which reduces turbu- lence, thus resulting in greater resistance to movement of tme grains. Menard recorded movement of grains 1.0 mm in diameter by current velocity of 18 cm/sec, and 3.0 mm in diameter by velocities of 30 cm/sec. 0n smooth surfaces, a velocity of 50 cm/sec was required to move a grain 3.0 mm in diameter. Twenhofel (1932) recorded similar data in his studies on currents. Physical variations in the grains alters any direct relationship between size and velocity, substantiating se- lective transportation as a result of size, shape, density, etc. It seems probable that water, like wind, is subject to "gusting" because of varying bottom conditions, and a great range in velocities might interrupt a current assumed to have uniform velocity and competency, thus complicating an already complex situation. Inman noticed that fine sand averaging 0.180 mm was the optimum size for movement by water. Velocities required for movement of a grain increased as the grains became larger or smaller than 0.180 mm. In correlating transportation of sand particles and currents, a general relationship of grain size to tidal currents was observed in San Francisco Bay by Louderback (1939). Krumbein and Aberdeen (1937) report a 168 :remarkable relationship between current and grain size and sorting in Barataria Bay, Louisiana. Currents are forced into a narrow entrance causing deposition of coarser, better sorted materials in the central portion of the bay. The fine, poorly sorted materials are deposited near the shores. -Alexander (1934) recognized deposits of rounded quartz sand concentrated in a belt of known prevailing currents on the continental shelf Plate 3 is an isopleth map of median diameters. Diameters range from near 10.000 mm at location 3 in the southeast corner of the bay, to 0.015 mm at location 27 in the deep water off Point Au Gres. Approximately 96 per cent of the samples fall within or less than the medium sand range. Of these, about 10 per cent are in the very fine sand or silt range. Sediments at locations 3, 21, and 49 are in the pebble, very coarse, and coarse sand range re- spectively. An area of relatively coarse material is in the southeast corner of the bay, extending eastward to Katechay Island. An area of generally small grain-size is circumscribed by locations 37, 27, 17, 7, and 16 on the north- west side of the bay. MEDIAN DIAMETER AND DEPTH OF WATER -— i In a body of water into which the influx of sediments is not too great, two types of sediment loads are carried. That which is coarse and is moved by traction (or possibly remain station- ary) and the fine—grain sediment which is carried in l J l l SAGINAW BAY MEDIAN DIAMETER ISOPLETH INTERVAL: .050 mm PLATE 3 170 suspension. The very fine materials tend to remain in suspension as long as the water is in motion either by wave or current action. Generally the optimum condition for settling out of fine sediment is in deep water. Current velocities are assumed to be very slight at depth, and unless the wave action is strong the bottom will remain undisturbed. Further- more, it has been proved that once a layer of fine material is layed down, its surface offers more resistance to movement of an individual grain than a surface covered by coarse materials (Inman, 1949). In Saginaw Bay, there is some question whether there is any deep water area not raked by wave or current action. Hough (1942) found coarse material deposits at depths of 140 feet in Cape Cod Bay which be attributed to wave action. Of course, wave action in open areas of large bodies of water is known to extend to greater depths. A general correlation can be made when comparing contour—line patterns of the depth and the median diamater isopleth maps (Pls. l and 3). Fine sediments are found in deep water at locations 37, 27, 17, and 16; and in somewhat shallower water at locations 6 and 7 north of the mouth of the Saginaw River. Fine-grained samples are common in the central part of the open end of the bay. It does not hold true, however, that fine sediments are restricted to deep water as some near-shore sediments taken from shallow ‘ — 1"- 171 water are fine to silty. These areas are protected and not swept by currents. Sample 41 falls neither into the category of sediment frwnn deep water nor protected area. It was taken from a depth of less than 20 feet a short distance off Oak Point iJl‘Vhat appears to be an exposed area. The median diameter (If the grains is 0.086 mm. This collection of fine-grained sedinmnt.near such an exposed shoreline may be explained by 'Uue projection of Sand Point and the islands to the west. It appears from the isopleth distribution of the data from the various physical properties of the sediments that the currents are deflected away from Sand Point toward Charity Island, swinging shoreward again in the vicinity of Hat Point. From Sand Point eastward, large accumulations of medium sand forms fine beaches. A few rocky prominences are the exception. It is thought that the sand accumulates on shore as a result of the prevailing winds constantly moving the sand shoreward. The shore east of Sand Point is relatively free from major bay currents and is not swept clear of sediment. In a comprehensive and interesting report on Huron County, Lane (1900) discusses the area between Sand Point and Port Austin. He attributes the large amount of sand accumulation here to rapid deepening of water off shore in contrast to the area from Sand Point westward where there is no break in profile between bay bottom and surrounding 172 lowland. The waves break quite some distance from shore, stranding the muds in marshes and flats. From Sand Point eastward, however, wave action ex- tends to the beach, and the undertow carries the mud back out to deeper water. The sand is left on the beaches. These shores trend northeast, facing for the most part the pre- vailing winds. The sand pushed up on the shore is carried inland and forms dunes from Port Austin to Port Crescent and Caseville. Dunes of lesser magnitude extend along the shore to the west of Caseville. The concentration of sand is attrubuted to the long fetch and partly to the prevalence of "on-shore" winds. Lane suggested that the Mississippian sandstone which underlies much of the area might be a source of the material. East of Port Austin, the shores become increasingly less sandy and the familiar rocky shore features of Point aux Barques are swept by waves and currents. Figure 10 shows the relationship between median diameter and depth of water. No linear correlation was found, although there is a concentration of medium-grain sand in the shallow depts. Fine sediment from 3.0 phi diameters and above are scattered throughout the range of depth. From this evidence it is seen that local conditions involving currents, bottom topography, grain shape, sorting, and density are greater factors in grain size distribution than depth alone. 173 00 a mp4; mo zhamo no 00 n5 0h mm 00 on 00 av 0.? mm 0m mm 0N ______ ___ «5.43 “.0 Ikamo m> «Em—24.0 24.0w: .0. ~33... 00.0 00.. 00.~ 00.n 00$ 00. _l 8313WV|O NVIOBW suun (o) 174 A similar condition exists in Buzzards Bay, Massachusetts where there is no correlation between depth and median diameter (Hough, 1940), emphasizing the factor of wave and tidal current action. The same situation holds true for Cape Cod Bay which is also relatively shallow for the most part. Here, local conditions play a greater role in the distribution of sediments than depth. Hough also noted in Cape Cod Bay that coarse material could be found anywhere, but the fines were restricted to deep water of the open bay and protected embayments. Barataria Bay sediments, as previously mentioned, show a strong dependency on currents rather than depth. Two types of San Francisco Bay sediments discussed by Louderback (1937) include fine sediments deposited at depth under normal conditions and coarse materials deposited at depth as a result of hydraulic currents due to tidal action. Lauf (1956) noted a distinct relationship between depth and median diameter in Grand Traverse Bay, Michigan, where the water reaches depths of over 500 feet. MEDIAN DIAhETER AND SKEWNESS -- In the medium sand range (1.5 - 2.0 or 0.175 - 0.350 mm) the average skewness is very close to zero. Sands coarser than 0.350 mm show a strong positive skewness. The finer materials are skewed to both the positive and negative sides (Fig. 11). MEDIAN DIAMETER AND CURRENTS -- The movement of sediment depends largely on particle size and current velocity. 175 mmuzimxm 00m; 000; 000. 000. 001 no. 00W 000. 00”! 00¢[. _ w fi_ __ mmwzgwxm m> mmhmzflo 250m: .: e53... e" e 0.0....‘e 0Q0 00; OQN 0Qn 00.0 09?. SllNfl (o) sauwvno NVIoaw 176 So long as the sediment supply does not exceed the trans- porting power of the water and the depth of the water is not too great for sufficient current velocity to move a sediment resting on the bottom, a correlation between grain size and currents can be established. In bodies of water in which there is a great range in depth, grain size acts as a depth indicator, decreasing as the depth increases. Grain size also serves as an in- dicator of current velocity, in which case it is commonly known that currents decrease in deep water. This, of course, is not necessarily true of surface currents. Since the water in Saginaw Bay is shallow throughout, and there is relatively little relief in bottom topography, sediments entering the bay become a function of the different currents. At the same time, the currents are regulated with respect to bottom topography, shore features, river influence, and winds. As the currents are altered by these factors, so the sediments are moved and adjusted to the hydraulic con- ditions which most nearly equal physical characteristics of the sediments. A general current pattern is outlined from a synoptic survey of Lake Huron by Ayers, et al, (1956). It is sug- gested that a current out of Lake Huron enters the north side of Saginaw Bay and emerges from the south side where it joins a current from the north as it passes around the tip of the "Thumb”. In antithesis to this supposition, it 177 has been pointed out by Hooper (1958) that strong winds from the southeast may cause Lake Huron currents to enter Saginaw Bay at Point aux Barques and exit at Au Sable Point. In either instance, it is assumed that the main flow of water roughly parallels the shore around the bay. Ayers, et a1, (1956) state that the outflow of the Saginaw River at Bay City is deflected to the south shore by, "...both prevailing west winds and the rotation of the earth" as well as currents coming from the northeast. It is also pointed out by Ayers that gravity and prevailing winds hold the current close to the shore during its eastward movement. The median diameter distribution follows such a pattern. Data obtained from the grain size analysis indicate that water is deflected toward Charity Island in the vicinity of Sand Point, then turns shoreward again near Hat Point. Coarse materials deposited in the southwest corner of the bay and eastward along the south shore verify the strong current deflection of the Saginaw'River. The currents in the central and northwest part of the western half of the bay are not fully understood. The glaciJLl Saginaw River channel extends eastward along the norfflx shore almost in line with what is believed to be the paid: of westward flowing currents from Lake Huron. Isopleth patterns in several analyses suggest that a west moving cur- rent is deflected away from the shore in the vicinity of Point Lookout. A large part is directed toward the center 178 oftme bay where it ultimately joins and probably helps (hfllect the Saginaw River inflow. A zone of coarse material tmems to indicate that currents continue in part to the westend of the bay in the shallow water along the north dune; however, the current patterns are generally weak and itis difficult to explain currents swinging shoreward after being deflected away from Point Lookout. Intermittent southeast winds and local shore currents may supply the force for more sand in this area. Drift bottle studies by Johnson (1958) indicate a very close correlation between surface currents and winds. He attributes the great variability in surface currents to constantly changing wind directions. This lack of definite surface current patterns was particularly apparent in the determine how western half of the bay. It is difficult to much effect.these variations in daily surface currents have on the over-all pattern of sedimentary deposition in shallow ‘wateru. Only a series of samples taken daily could possibly It is reflect changes of the order described by Johnson. my'lnrlief, however, that the gross picture alters very little ancl the; distribution of sediments according to size coincides with the prevailing currents of the bay which may be altered This cannot be traced accurately by drift bottles. locally. The median diameter pattern in the center of the open of? the bay suggests a lesser current which deflects the curl main current stream to the south shore near Hat Point. 179 Studies of Lake Huron indicate that currents penetrate into {me outer reaches of the bay varying distances, but as yet their exact course has not been accurately determined. Ayres, et al, (1956) discusses Saginaw Bay in terms of a typical estuary. "In the spring there is usually a slowly rotating eddy in the center of an estuary and possibly the bay has a similar feature at that time of year." One can only speculate on the effect such an eddying would have on the sediments in moderately deep water. Many variables are introduced which make interpretation difficult and unreliable at times. If it were possible to eliminate the depth factor, if all the grains were of equal density, shape, and texture, and if the current velocities were not;a1tered by wind or surface features, correlations could be established. It seems then that median diameter, when associated with current movement and interpreted in light of all the 'variables, can be a very useful tool in determining sediment distribution. A [— __._____. __ _._ SORTING Sorting, as defined on page 97, is a function of the deviation of the maximum and minimum grain sizes from the median. Sorting, therefore, may be directly related to the hydraulic conditions existing in a body of water as well as the physical properties related to the individual grains. Russell (1939) divides sorting action into two types: One he terms ”local" sorting which involves the assortment of particles at a particular locality, and the other is ”progressive” sorting which is the assortment of particles in the direction of transportation. The latter seems to apply best to currents that are unidirectional and are not affected by varying winds. Rivers or longshore currents are related to this type of current. Russell states further that, "The most important factors involved in both types of sorting appear to be the size, shape, and specific gravity of the particles; the velocity, degree of turbulence, viscosity, and specific gravity of the transporting agent." Trask (1930) set up values for degrees of sorting which are commonly accepted and much quoted. He determined that a value of 2.5 (log So 0.397) or less indicates a well sorted sediment, a value of 3.0 (log So 0.477) a sediment 180 181 of average sorting, and any values greater than 4.5 (log So 0.653) were designated as poorly sorted sediments. It should be kept in mind that Trask's sorting is geometric and cannot be arithmetically compared. An isopleth map of log Sorting is shown on plate 4. Sorting values range from very poor, 6.116 (log So 0.786) in Sample 2, to 1.179 (log So 0.072) in Sample 69. Nearly 75 per cent of the samples have a sorting value well above that considered good according to Trask's factors. It should be remembered that Trask used the 25 and 75 percentiles in his calculations of sorting, thus only 50 per cent of the sedi- nmnt was taken into consideration. Sixty-eight per cent of the distribution, between the 16th and 84th percentiles, was used in this investigation. It was found that by using 18 per cent more of the distribution curve the sorting was de- creased by nearly 50 per cent in many samples. Poor sorting is restricted to two general areas. One zone parallels the north shore in the vicinity of Point Au Gres, outlined by locations 18, 29, and 38 (Sorting for Sample 38 is approximated).1 1When there is extremely coarse or fine material in ‘ l"mple, often the cumulative curve does not intersect the 16 ‘nd 84 per cent lines respectively. Under such circum- lt‘ncos the cumulative curves are projected to the 16 and 84 per cent lines so that sorting can be estimated. SAGINAW BAY log SORTING DISTRIBUTION ISOPLETH INTERVALI 0.050 Units PLATE 4 183 These three samples were taken from moderately shallow water on the edge of the glacial Saginaw River depression. A narrow band of poorly sorted sediments, in the vicinity of locations 27 and 36, lies within the trough (Sample 27 is approximated). A second zone, somewhat more irregular, extends west- ward from Katechay Island at location 21 (sorting approximated) in a trough of somewhat deeper water to locations 1, 2, 3, and 4(7). Sample 3 is approximated and no sample was recovered from location 4. Sediments at locations 10 and 11, lying between locations 21 and l, possess only average to below average sorting. Samples 1, 2, and 3 are probably closely related to Sample 55, taken southeast of the mouth of the Saginaw River, and Sample 4. The explanation for this poor sorting will be discussed later. An area of moderately poor sorting is circumscribed by locations 7, 16, 17, and 27. A similar area is outlined in the vicinity of Oak Point and Hat Point by locations 41, 48, 49, and BT—26. Sample 13 has only moderate sorting. The area with best sorting lies in the shallow water Off Sand Point toward Charity Island, where Samples 32, 38 2 and 34 were taken. SORTING AND MEDIAN DIAMETER -- The relationship between sorting and median diameter has been discussed at considerable length by many students of sedimentation. 184 From the definition of sorting one can see that to have a well sorted sample the grain-size distribution must be small. Must of us have observed such conditions in uniform beach sands which have been worked by both waves and wind, and as a result the fine materials have been carried to deep water in suspension by the tides or have been blown farther inland by the wind. The sand particles found on the beach were deposited there by waves or currents suited to carrying that particular grain size. There are many conditions which may alter this uniform distribution of particles, causing both coarse and fine materials to exist together. This may occur when the supply of material exceeds the capacity of the transporting agent (Kuenen, 1950); however, this is not likely to happen in Saginaw Bay where the surrounding lowland is drained by rivers with very low gradients. With the exception of the Saginaw River sediments, it is thought that other rivers carry silt and fine sand into the bay. Figure 12 shows the relationship between sorting and median diameter. The concentration of medium sand, 1.5 to 2.5 0, occurs in sediments with a log Sorting of 0.200 to 0.100. The finer sands generally possess somewhat poorer sorting; however, the poorest sorting occurs in sediments of 0.500 mm and coarser. (Sorting for Samples 2, 3, 4, 21, 27, and 38 are approximated and are not plotted on the graph.) 185 ozlmom 3: 000. . 00». 000. 00m. 00¢. 00m. 00m. 00.. 000.00..I . _ . . _ . _ _ . _ _ _ .485 ozfimom a, 55.245 24.82 . II .N. 2:3... . . II100.. . .. u . Iloo.~ . loos Illooé . IL 00.0 UBIBNVIO NVIOBW Slmn W) 186 It can be said with reservation that poorer sorting occurs most frequently in the finer sediments, or better sorting tends to occur in the medium sand range. Inasmuch as grain size appears largely as a function of currents, the sorting in Saginaw Bay also can be related to these same factors. Inman (1949) relates the degree of sorting to the ability of a fluid to sort out one grain size from another. The variations in sorting of sands from the bay are due to local conditions resulting from changes in current velocity, source and amount of material supplied, and depth of water. It is difficult to say how much material has been carried into the bay from the surrounding glacial drift. Cores removed from the navigation channel by the Corps of Engineers, Detroit, (1956) record upwards of 50 feet of sediment. One cannot say without further investigation whether the material is post glacial or not. It is sug- gested by some that a body of water receiving sediment from glacial drift, which is already poorly sorted, would neces- sarily have poorly sorted sediments. This might be expected in an area in which large quantities of material are being carried into the bay, but certainly this is not the case in Saginaw Bay. The sluggish streams probably sort the material to a considerable degree before they enter the bay. It seems more probable that the zones of pebbles and cobbles represent remnants of coarse materials left by the 187 glacier as it retreated. Since that time, wave and current action has been unable to move them any appreaciable distance. A more extensive investigation of the areas of coarse materials and "rock” bottom is needed before this question can be answered. Hough (1942) found a similar situation in Cape Cod Bay, Buzzards Bay (1940), and in Lake Michigan (1935). He in- terpreted the Lake Michigan sediments as a lag concentration of the coarser constituents of glacial till produced by wave and current action. In each case it was difficult to determine whether the material was left by glaciers, represented an old beach, or concentrated since glaciation as a result of severe wave action. In contrast to Saginaw Bay, lumen and Chamberlain (1955) noted in the bay areas of LaJolla, California; Rock- port, Texas; and the Mississippi delt area that the distri- bution of sediment is dependent upon the type and amount of sediment and process of transportation. In areas where normal sand load is deposited into the bays, the fines are carried into deep, quiet water, and sandy beaches are built up where the fetch is sufficiently great to generate waves. In regions where the sediment load is greater than the trans- porting agents, such as in the confined areas near the Miss- issippi delta, both fine and coarse sediments occur together, and they reflect strongly the source area from which they came. 188 Studies made on several bodies of water throughout the world show a general relationship between grain size and sorting. It may be assumed with minor exceptions, depending largely on a third factor — depth of water, that good sorting is generally associated with sand particles (0.150 mm plus or minus), and poor sorting occurs in varying degrees toward the fine and coarse ends of the distribution. Poor sorting in the fine sediments may be explained in this manner: During extreme conditions in a given body of water strong currents or wave action carry coarse materials into areas of normally quiet water. Large pebbles or cobbles are rolled down slopes into deep trenches or storm waves carry coarse material into protected areas. The coarse materials are destined to be forever mixed with the very fine sand and silt. Ice rafting may also introduce heterogenity to a uniform mixture of fine sediments. Inman (1949) notes further that poor sorting in fine sediments often may be attributed to the fact that a fluid does not readily differentiate between the smaller diameters, but rather tends to carry particles ranging from clay to fine sand with equal ease. If good sorting in very fine sediments is prevelant, it may be due to the great differences in set- tling velocities of fine particles, although the depth factor in Saginaw Bay is likely to rule out such sorting. Another phenomenon which may cause poor sorting is the transportation of very fine sediments by bubbles on or 189 near the surface of the water. This has been observed by Menard (1950) and McKelvey (1941), and is regarded as a means of carrying sizeable quantities of material in agglomerates composed of bubbles and grains held together by surface tension. Transportation of this sort is controlled largely by surface currents and deposition occurs whenever and where- ever surface tension is broken by turbulence or some other disturbance. Deposition is independent of any subsurface hydraulic conditions. The relation between poor sorting and fine grained sediments has been noted by many students of sedimentation. Trowbridge and Shepard (1932) found a general relationship between size and sorting in Massachusetts Bay sediments. Silts from the deeper water showed poorer sorting than the fine and medium sand near the beaches. This suggested two sediment loads carried under different conditions. Rough (1940) found poor sorting in the fine sediments in contrast to good sorting in the sand size particles in Buzzards Bay, Massachusetts. In his study of Cape Cod Bay (1942) he noted good sorting in coarse sediments. The fine sediments on the other hand were not so well sorted although the sorting factor was about 2.0 according to Trask's scale. Griffiths (1951), in a study on some Caribbean uncon- solidated sediments, found a good correlation between size and sorting. He noticed, however, that factors such as length of time and "intensity" of deposition tend to alter 190 the relationship. In essence, this means the longer the sediment is under the effect of waves and currents the better the correlation. Thus when the supply of material exceeds the transporting power, the sediments never reach a state of equilibrium through long reworking. Griffiths suggests that poor sorting associated with coarse materials may be a result of immature sediments deposited after a short distance of aqueous transport. In analogy to this supposition, locations 1, 2, 3, 4, 54, and 55 represent an area which may intermittently receive large quantities of coarse materials from the Saginaw River as its sediment load is deflected upon entering into Saginaw Bay. This area is not only one of generally coarse, but one of very poorly sorted sediments. The effect of this deposition extends as far eastward as Katechay Island (Sample 21). In the Red Sea sediments, Shukri and Higazy (1944) found good sorting in the 0.150 mm range. Sorting becomes poorer in the very fine sediments. Krumbein and Aberdeen (1937) related sorting with the same conditions which con— trol median diameter, and noted a decrease in median diameter with a decrease in sorting. It is likely that better sorting may be found in the extensive sand beaches from Sand Point toward Point aux Barques, including Oak Point and the Huron dunes area. This area, and the shoreline directly across the bay in the vicinity of Tawas city, are open to wave action as a result of greater fetch. 191 It is noted that near Oak Point on the southeast side of the bay where large quantities of sand have accumu- lated, Sample 41 from this locality is very fine-grained and has only moderate sorting. Sorting and median diameter isopleth maps suggest that the main currents deflected around Sand Point do not move shoreward again until in the vicinity of location 49 off Hat Point. Here, coarser material and a noticeable lack of sorting is present. The area around location 48 was too rocky to produce any sediment. SORTING AND DEPTH OF WATER —- Wave action and cur— rents are factors governing distribution and sorting of particles; and it is generally agreed that these factors are more active in shallow water. Better sorting on beaches or in shallow water results from waves or currents carrying away the fine particles. The sand particles are distributed according to current intensity and the hydraulic equivalent of the grains. Figure 13 shows no linear correlation between depth of water and sorting. Most of the samples possessing a log Sorting of less than 0.200 were taken in water less than 50 feet deep. It is interesting to note that most of the sediments Possessing poor sorting were in water less than 25 feet deep. From this information it must be concluded that sorting in Saginaw Bay is only locally related to depth of water, and Vhere depth of water is related to sorting, the water is not disturbed greatly by currents or wave action. 192 om mm mwh<3 no Ihamo om ms. Oh no cm on on 0v 0v on On mm ON 0. O. m___ _ «3.43 no Ihdmo m> oszom. .m. 333.... _ _ _ nIl,OO.. II. CON. ll com. I] 00¢ llroom. I 000. owllsos 6m 193 SORTING AND SKEWNESS -- There is no linear cor- relation between skewness and sorting (Fig. 14). Those samples which are highly skewed to the fine side also are poorly sorted. The preponderance of the samples which show very little skewness have very good sorting. Hough, during his work on Cape Cod sediments, also found good sorting in the samples which had log zero skewness and poor sorting in sediments which were skewed to the fine side. SORTING AND CURRE§2§ -- Sorting and median diameter are similar in that they are dependent on many of the same variables. The "sorting out" or selecting of sand according to shape, size, and density by water action lends it well to current association when the various hydraulic properties necessary to assert the materials are known. When the depth factor is not great, sorting becomes In: important device in measuring current trends. But even illough depth is always a factor to some degree it merely becomes another moment to which currents will conform and 1*16 sediments in turn will adjust. Sorting, therefore, may 3&Ft only outline the current patterns as controlled by depth, deids, and surface features, but may indicate the kind of sediments which are being moved. 194 CON. 099. 25. mmm23wxm 03 00‘ 099 CON 009 00”! OCT! mmwzgwxm xv. _ _ m> uzimom ~53... _ _ m llOOfi ILOQN [1099 IIOQ¢ Ilan IIOOQ nl. ook. 2;. SNIIUOS HEAVY MINERALS From a portion of sediment split from the original sample, two size-grade fractions were arbitrarily established. The 0.177 mm (80) sieve, which falls between fine and medium sand in the Wentworth scale, was chosen as the dividing line between ”coarse" and "fine" fractions. Each fraction consisted of two grams of sample, except where the sediment was either too fine or too coarse to allow collection of two grams of sample in both size grades. A heavy mineral separate was made by placing the sand in a funnel filled with bromoform (Sp. G. 2.68) and allowing the heavies to settle. This process is discussed in detail by Krumbein and Pettijohn (1938). The heavies were weighed and the percentage of the two size-grades calculated. Data are shown in Tables 124 and 125. The total heavy mineral percentage for the entire sanque is shown in Table 126. The light fractions were saved for roundness and sphericity determinations (p.238). The distribution of heavy mineral percentage is shown ‘"1 Plate 5. Heavy mineral percentages range from 0.624 in sfimpde 27 to 11.508 in Sample 8. Nearly two-thirds of the 8amples contain between 1.000 and 3.000 per cent heavies. It i-s interesting to note that of the seven samples that ”n tain more than 5.000 per cent heavy minerals, all but three are within three miles of the shore and all but two are “thin five miles of the shore. 195 196 Table 124 HEAVY MINERAL PEBCENTAGES Tyler Sieve Size: (4) .177 mm diameter Height Weight Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 1 2.0030 0.0184 0.000. 2 2.0003 0.0101 0.055 3 2.0000 0.0194 0.070 5 2.0003 0.0071 0.355 0 2.0000 0.0057 0.285 7 2.0000 0.0182 0.010 8 2.0005 0.0150 0.705 0 2.0000 0.0003 0.405 10 2.0007 0.0211 1.055 11 2.0003 0.0157 0.785 12 2.0001 0.0120 0.045 13 2.0002 0.0130 0.080 14. 2.0001 0.0100 0.545 15 2.0004 0.0080 0.400 lo 0.5032 0.0020 0.438 17 2.0000 0.0050 0.205 18 2.0000 0.0158 0.700 In 2.0000 0.0004 0.470 21. 2.0002 0.0200 1.000 22 2. 0004 0.0030 0.180 23 2.0004 0.0073 0.305 24 2.0001 0.0143 0.715 Sample Number 25 20 27 28 29 30 31 32 33 34 35 30 37 38 39 41 ‘42 43 ‘45 ‘46 ‘47 ‘49 50 51 Weight of Sample 2.0000 2.0001 1.9500 2.0001 2.0004 2.0002 1.3792 2.0003 2.0000 2.0001 2.0002 2.0003 2.0001 2.0000 2.0008 1.9583 2.0004 2.0001 2.0002 2.0000 2.0007 2.0007 2.0005 2.0008 197 Table Heavy Minerals 124 Weight of 0.0305 0.0182 0.0050 0.0103 0.0150 0.1079 0.0031 0.0910 0.1245 0.0407 0.0002 0.0101 0.0057 0.0157 0.0153 0.0118 0.0075 0.0200 0.0007 0.0078 0.0080 0.0108 0.0004 0.0071 HEAVY MINERAL PERCENTAGES, continued Percent of Heavy Minerals 1.825 0.910 0.280 0.515 0.750 5.395 0.225 4.549 0.230 2.035 0.310 0.805 0.285 0.785 0.705 0.603 0.375 1.000 0.335 0.390 0.430 0.540 0.320 0.355 198 Table 124 HEAVY MINERAL PEBCENTAGES, continued Weight Height Percent Sample of of of Number Sample- Heavy Minerals Heavy Minerals 52; 2.0007 0.0124 0.020 53 2.0000 0.0214 0.070 54 2.000? 0.0134 0.070 55 2.0000 0.0082 0.410 50 2.0004 0.0219 1.095 59 2.0003 0.0100 0.530 01 2.0000 0.0133 0.005 02 2.0000 0.0008 0.340 03- 2.0000 0.0021 0.105 04 2.0000 0.0181 0.905 05 2.0002 0.0140 0.700 00 2.0003 0.0130 0.050 07 2.0003 0.0144 0.720 08 2.0000 0.0070 0.380 09 2.0005 0.0010 0.050 199 Table 125 HEAVY MINERAL PERCENTAGES T ler Sieve Size: (-1 .177 mm diameter Height Weight Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 1 2.0005 0.0839 4.149 2 2.0000 0.1192 5.958 3 2.0002 0.0978 4.890 5 2.0004 0.0041 3.204 0 2.0005 0.0047 3.234 7 2.0008 0.0092’ 3.459 8 2.0001 0.4445 22.224 9 1.5394 0.0500 3.038 10 2.0005 0.0009 3.344 11 2.0002 0.0830 4.180 12 1.9450 0.0009 3.440 13 2.0002 0.0840 4.230 14 2.0002 0.0557 2.785 15 2.0000 0.0977 4.885 16 2.0001 0.0234 1.170 13? 2.0004 0.0712 3.559 18 2.0002 0.1130‘ 5.049 19 2.0001 0.1342 0.710 21 2.0010 0.0900 4.828 22 2.0007 0.0434 2.100 23 2.0001 0.1083 0.015 24 2.0005 0.0580 2.044 200 Table 125 HEAVY MINERAL PERCENTAGES, continued Height Weight Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 25 2.0004 0.0000 3.299 20 2.0000 0.0505 2.825 27 2.0007 0.9547 1.982 28 2.0001 0.1482 7.410 29 2.0000 0.1383 0.913 30 2.0005 0.0708 3.539 31 2.0000 0.0338 1.090 32 2.0003 0.3493 17.402 33 2.0001 0.1749 8.745 34 2.0002 0.2728 13.039 35 2.0001 0.0810 4.080 30 0.0900 0.0401 0.018 37 2.0003 0.0051 3.255 38 2.0000 0.0744 3.720 39 1.0503 0.1058 10.010 41 2.0007 0.0489 2.444 42 2.0004 0.0552 2.759 43 2.0001 0.1088 8.440 45 2.0002 0.0059 3.295 40 2.0007 0.0955 4.773 47 2.0004 0.0772 3.859 ‘49 2.0000 0.0805 4.024 50 2.0000 0.0041 3.205 51 2.0002 0.0505 2.825 201 Table 125 HEAVY MINERAL PERCENTAGES, continued Weight Height Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 52 2.0002 0.1820 9.129 53 1.3433 0.1510 11.241 54 2.0000 0.0520 2.030 55 2.0000 0.0500 2.540 50 2.0000 0.2523 12.015 59 2.0000 0.1229 0.145 01 2.0001 0.1077 5.385 02 2.0000 0.0529 2.045 03 2.0000 0.0790 3.950 04 2.0000 0.1270 0.380 05 2.0000 0.0907 4.835 00 2.0003 0.0941 4.704 07 2.0002 0.1843 9.214 08 2.0002 0.0533 2.005 00= 2.0002 0.0335 1.075 202 Table 126 AVERAGE HEAVY MINERAL PERCENTAGES i .177 mm Fractions Height Weight Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 1 4.0035 0.1014 2.533 2 4.0009 0.1383 3.457 3 4.0002 0.1172 2.930 5 4.0007 0.0712 1.780 0 4.0005 0.0704 1.700 7 4.0008 0.0874 2.184 8 4.0000 0.4004 11.508 9 3.5394 0.0053 1.845 10 4.0012 0.0880' 2.199 11 4.0005 0.0993 2.482 12 3.9451 0.0798 2.023 13 4.0004 0.0982 2.455 14 4.0003 0.0000 1.005 15 4.0004 0.1057 2.042 10 2.5933 0.0200 1.003 .17 4.0004 0.0771 1.927 :18 4.0002 0.1288 3.220 19 4.0001 0.1430 3.590 21. 4.0012 0.1100 2.914 22 4.0011 0.0470 1.175 23 4.0005 0.2050 5.139 24 4.0000 0.0732 1.830 .3ple who! 203 Table 120 AVERAGE HEAVY MINERAL PERCENTAGES, continued i..177 mm Fractions Weight Height Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 25 4.0004 0.1025 2.502 26 4.0001 0.0747 1.807 27 3.9567 0.0247 0.024 28 4.0002 0.1585 3.902 29 4.0010 0.1533 3.832 30 4.0007 0.1787 4.407 31 3.3798 0.0309 1.092 32 4.0000 0.4403 11.000 33 4.0001 0.2995 7.487 34 4.0003 0.3135 7.837 35 4.0003 0.0878 2.195 36 2.0909 0.0622 2.300 37 4.0004 0.0708 1.770 38 4.0000 0.0901 2.253 39 3.0571 0.1211 3.961 41 3.9590 0.0607 1.533 42 4.0008 0.0627 1.567 43 4.0002 0.1888 4.720 ‘45 4.0004 0.0726 1.815 46 4.0007 0.1033 2.582 47 4.0011 0.0858 2.144 49 4.0013 0.0913 2.282 204 Table 126 AVERAGE HEAVY MINERAL PERCENTAGES, continued 1+ .177 mm Fractions Weight Weight Percent Sample of of of Number Sample Heavy Minerals Heavy Minerals 50 4.0010 0.0705 1.702 51 4.0010 0.0036 1.590 52 4.0009 0.1950 4.874 53 3.3433 0.1724 5.157 54 4.0004 0.0660 1.650 55 4.0000 0.0590 1.475 56 4.0004 0.2742 6.854 59 4.0003 0.1335 3.337 61 4.0001 0.1210 3.025 02 4.0001 0.0597 1.492 63 4.0000 0.0811 2.028 64 4.0000 0.1457 3.043 65 4.0002 0.1107 2.707 00 4.0000 0.1071 2.077 67 4.0005 0.1987 4.907 68 4.0002 0.0609 1.522 69 4.0007 0.0345 0.862 1 1 SAGINAW BAY HEAVY MINERAL DISTRIBUTION ISOPLETH INTERVAL .500 Percent Scale hounds of Fee? n'ls' PLATE 5 -1 . I 4396-5 55"1' .111 s 206 Sample 8 near Nayanquing Point in the northwest corner of the bay contains 11.508 per cent heavies; and Sample 32 off Sand Point contains 11.006 per cent. In the fraction finer than 0.177 mm, Sample 8 contains 22.224 per cent heavies and Sample 32 contains 17.462 per cent. An area of high heavy mineral content is outlined by locations 23, 33, 34, 43, and 67. Approximating Sample 32 are Samples 33 and 34 which contain nearly 7.000 per cent heavies. Sample 23, which was taken a few miles west of Katechay Island, contains 5.130 per cent, and Samples 67 and 43 north of Charity Island contain 4.967 and 4.720 per cent respectively. Other high values occur somewhat erratically throughout the bay. HEAVY MINERALS AND MEDIAN DIAMETER —— The relation- ship between heavy minerals and median diameter is shown in figure 15. It is immediately obvious that there is no linear correlation between the two, and upon comparison of the dis- tributions on Plates 3 and 5, no relationship is apparent. Heavy minerals in quantities of over 3.000 per cent “IVE restricted to sediments with diameters of 1.0 to 2.5 phi Inlitm (0.500 to 0.125 mm), but those sediments containing 1988 than 3.000 per cent show no restrictions. It is interest- ing; to note that the three samples which contain 1.000 per can”t or less occur in sediments with median diameters smaller than 2.5 phi units (0.125 mm) which is contrary to what is °°mmon1y found of heavy mineral occurrence. 207 32: as $3246 on 0.4 24 .052 o.m 0.... _____ mwkwszzo 24.0w: 2 332350 .253: >231 .m. 23E _ I13 1 C.“ Ill 0d IIION III 0.0 IJ. 0.0. 0.: 3901N3333d ‘IVHBNIW AAV3H 208 An increase in heavy minerals with a decrease in grain size has been observed by many in the study of sediments. Russell (1930), Rittenhouse (1943) and Rubey (1933) found this to be generally true. Rubey also associated mineral accumulation as a result of other factors which include sorting, shape, specific gravity, abrasion, and amount and kind of minerals at the source. Inasmuch as there is a higher percentage of heavy minerals in the coarse sediments in Saginaw Bay, it becomes obvious that size alone is not a strong factor in heavy mineral concentration. But the contrast in the data obtained from heavy mineral separates in the fractions coarser and finer than 0.177 mm shows plainly that the heavy minerals are concentrated in the finer fractions of each sample. This, in a large part, is due to the fact that zircon, rutile, apatite, and titanite, common in many sediments, occur as minute accessories in igneous rocks. Often these'heavy min- erals occur as aggregates in the coarser fractions and are iden tified as rock fragments. Russell (1936) found such min— erals as pyroxenes and amphiboles in glacial derived sediments, increasing in the 100-150 sieve range (0.125 m), then de- °reaming again in the finer sizes. Garnets have a similar t‘mdeney; calcite was found more abundant in the 200 (-) range (0,062 mm). The metallics, with a high specific graVi ty, increase in percentage in the smaller size ranges and th en decrease in the very fine 81238- 209 Rubey (1933) contends that to separate all heavies less than a given size to determine heavy mineral ratios, tends to emphasize variations due to abrasion and size distribution at the source. Using one size-grade has certain advantages in that it eliminates variations caused by abrasion and size distribution, and the physical and optical properties of the minerals are nearly the same. But in choosing just one size, the sorting factor according to the particular size chosen enters into the problem. A possible solution may lie in the average of at least two (iifferent size fractions. As a result of such variations, many feel that great czare should be taken in making interpretations from heavy xnineral data when samples are represented by a great range it) size and sorting. HEAVY MINERALS 4gp DEPTH or WATER -- In comparing Plaites 1 and 5, a marked relationship is noted between heavy mixierals and depth. Figure 16 shows, in spite of any lack of limiear correlation, that the higher heavy mineral percentages occtrr in the shallower depths. Of those samples containing 3.000 per cent or more heavies, 80 per cent occur in water 1988 than 25 feet deep, and nearly 70 per cent in water less than 1.5 feet deep. This tendency of heavy minerals to concentrate in sha11~crw water is closely associated with the sorting factor or 111*! sediments. Certain areas appear to be conducive to mmk<>> “.0 theme cm as on em om mm On By ow on On mm ON n. O. m o 210 ___ _______4_fifi_ mmh<>> no Ihamo . . . . . . . 2 ”8328me 4452.2 >> wwdhzwummm J> w0>¢wI .m. . _ o.ao.m _ _ . _ II 0.0. Q: 0.N. 39V1N3383d 1V UBNIW AIWBH 216 EREPARATION FOR IDENTIFICATION -- A portion of the heavy mineral residue was cleaned and mounted in ARICLOR1 (n:1.68). Care was taken to prevent a biased sample due to size variation, shape, density, and magnetic properties in the minerals. Several methods of heavy mineral sampling are discussed by Otto (1933). The heavies were passed through the 80 sieve (0.177mm), and those remaining on the 100 sieve (0.149 mm) were mounted for identification. This provided a suite of heavy minerals in which the optical properties were uniform for any one specie. By eliminating some of the fine and coarse sizes there is a tendency to eliminate certain mineral species altogether. Certain species, as shown-by Russell (1936), occur in greater frequency in the smaller sizes. The writer feels that by choosing a size grade common to all samples, relative mineral percentages may be established which might show Some relationship to the physical environment in which they are presently adapted. This appears as the only logical approach since the minerals are derived from glacial drift and cannot be expected to show any definite arrangement with regard to their origin. Standard methods for mounting heavy minerals for °Ptical identification may be found in any textbook of sed i mentary petrology- 1ARACLOR #4465: Monsanto Chemical Corp., St. Louis, Mo. 217 MEAVY MINERAL_GRAIN COUNT —— The degree of use- fulness of data obtained from a heavy mineral analysis varies as the source of the heavy minerals varies. Thus, conclusions (Trawn from certain heavy mineral data are sometimes open to ({uestion. Unavoidable human errors may also be a factor, (xf which the three most prominent are involved in (1) sampling, (2) laboratory procedure, and (3) mineral identification. Each sample at best represents only an infinitesimal puart of the parent; therefore, great care should be taken in olitaining an unbiased sample which will best suit the needs ()f the problem. It is from these individual samples that tlie final gross relationships and conclusions will be drawn, amid any error in sampling may be magnified many times in the final data. When a large number of samples are involved, including a large mineral suite, errors in mineral identification are liJsely. Generally it is agreed that this error can be reduced by' increasing the number of grains counted on each slide. {“18 question then arises, how many grains should be counted? Counidng large numbers of grains, 500 to 1000 per slide, is 1Ilbor’ous and the results are not justifiably profitable if a 8mfiller number can be counted with little or no addition to the error. Many have proposed mathematical methods for determi— nation of the optimum number of grains to be counted, including facfnxrs for sampling and laboratory errors. Dryden (1931). 218 Krumbein and Rasmussen (1941), and Sindowski (1941) are some of the major contributors. In every new problem, the amount of error which can be justified must be a function of the sensitivity of the problem as regards the heavy mineral count. As a means of determining the optimum number of grains to be counted, the writer chose at random one slide on which six areas were laid out. In each of these areas 100 grains were counted, making certain that no grains were counted twice. Four easily recognizable minerals were chosen for the count, and although all minerals crossed by the traverse were counted in each 100 unit, only four species were identi- fied specifically. To obtain an average for each grain count from 100 to 600, all possible combinations were taken for 100, 200, 300, 400, 500, and 600. These combinations were found to be 6, 15. 15, 12, 6, and 1 respectively. One can see at once that '“He mean for the six 100 grain counts will be the same as the mean for the one 600 grain count. To show a numerical dif- ference in the counts only 100 to 500 were used in the final analysis. An average for each combination was determined and amean for the whole count calculated. The standard deviation for each group of combinations and the standard deviation of the mean of the combinations in each group was determined. The data are shown in figure 19. 219 Fiducial probability is often used by statisticians to express their confidence that the mean of a population will fall within given limits. Fiducial limits‘or "confidence limits" are merely limits within which a population mean might fall (Dixon and Massey, 1957) or, "the degree of confidence which the statistician has in his conclusions" (Croxten and Crbwden, 1947). Confidence limits are not exact statements (:oncerning the probability that the mean of the parent must :fall within given limits. The fiducial limits were determined by multiplying tale standard deviation of the mean of 100 grains by 2.6, or tdiree standard deviations from the mean. This defines the liJnits on either side of the mean, thus establishing the probability that 99.5 times m of 100 the sample mean will fall within these limits. The standard deviation of the mean for 100 grains was determined by the equation: crlOOEE P/Jn U-Wl is the standard deviation of the mean where: of 100 grains, P is equal approximately to the standard deviation of the parent distribution, and n is the number of combinations which went into each sample Data from two of the minerals in the grain count show tha't' there is considerable room for deviation in the 100- coull‘t range, but the limits become quite narrow in the 200 220 Garnet _ 6 (_ Fiducial Unit f/lOO gr x 100 2.6 x Limits Range 100 3 2.79 6.83 1.14 2.96 3.87- 9.79 5.92 200 5 1.67 6.83 0.43 1.12 5.71--7.95 2.24 300 6 1.21 6.77 0.31 0.81 5.96- 7.58 1.62 400 11 0.95 6.87 0.27 0.70 6.17- 7.57 1.40 500 8 0.57 6.85 0.23 0.60 6.25- 7.45 1.20 Hornblende _ _ Fiducial Unit 2/100 0’ x (100 2. 6 6’1: Limits Range 100 13 2.76 13.0 1.13 2.94 10.06-15.94 5.88 200 13 1.64 13.0 0.42 1.09 11.91-14.09 2.18 300 15 1.10 12.9 0.28 0.73 12.17-13.63 1.46 400 10 1.14 12.9 0.33 0.86 12.04-13.76 1.72 500 17 0.84 13.1 0.34 0.88 12.22-13.98 1.76 I’igure 19. Statistical data on Heavy Mineral Grain Count Determinations. t0 500-count range. It can be seen that the ratio between the: 300 to 500-count and 200 to 300-count in the two minerals chosen is negligible. Although the ratio between the 200 to 500~count is larger, it falls well within the limits of necessary accuracy and does not merit counting 500 grains per- slide. 221 HEAVY MINERAL SUITES —— A suite of twenty—eight mineral species were identified in the Saginaw Bay sediments. Mineral aggregates were identified as rock fragments. The minerals are shown in their relative percentages on Tables 127 and 128. Approximately half of the minerals were found in every sample, although many individuals occur in very small amounts. Augite, hornblende, epidote, clear garnet, and white metallic opaques are most abundant. Of these, hornblende is present in frequency up to 50 per cent. The metallic opaques, which include largely magnetite, hematite, and a small quanti- ty of ilmenite, occur in amounts up to 40 per cent. Clear garnets, epidote, and white opaques are rarely in excess of 25 per cent. The amphiboles and pyroxenes are typically elongate for the most part and commonly are rounded on the ends. Many grains have been cleaved and are quite angular. Epidote is generally well rounded and in some grains the surfaces are 8everly pitted. Both clear and pink garnet ranges from 8harply angular and irregular to well rounded grains. Minerals which often occur as accessories in igneous rOCkB; apatite, zircon, tourmaline, and rutile are typically "911 rounded. In some samples euhedral to subhedral zircon °rY8tals show only slight effects of abrasion. Micas are rare. Most noticeably rounded, regardless of size, are the black (and red) metallic opaques. Grains so perfectly rounded that they resemble shot are common. This high degree 01 222 eattoueag BattilJHOJ 0 53 C CD 0 a euexoonaq o.m s n.em n.n c.« o.“ n.- c.w n.m n.~ o.e~ 0.0 N u n.o o.m n.m n.~ o.o n.~ n.m n.e n.e s n.~ o.~ n.w u o.m o.¢ e.v o.~ 0.9 o.m n.e o.» o.~ 0." u.n e.~ e.v o.» n.v n.m n m m a? J I. o m u a u t u a... 0 o e .w d .o m n n a 8 B I atmu n.0u D e a 0'" seubsdo OIII'1OK hen tenwusm seam ensue .33 bp~.elo¢~.e one nu uniaenwz bras: we euevseeuem hm“ OHAJH v.0 con cov tenets aura C O O O Q' I”. p. e p. 1. stung) Ix‘IOID epuetquaog n.a c.uu n.o o.~u 0.0 c.0u o.¢~ coca oovn o.on Ostfinv Nu an ca 0) p4 Jequnu etdmeg 223 81:10:83; euttvuanog zedo; e m euaxooneq ID 0 e N e N °$I“‘$I& t noostz coma n.o~ n.0H 0.m~ n.w e.o~ c.hn now wood senbedo eaiqg hem resumem anona< e.H e.w o.~ n.mm n.u n.c~ n.m n.m~ u e.om e.~ n.e~ I new 7 m.m N e.e o.m a.» e.” n.o~ H H J 9 o 1 m B T. T. O I d O 9 .D 0 m d .. h n 8 I O 0 O o e H 0 e I) zanxvo anti sane oeatm as na~.caan~.a .smu oases en» su ensues“: hbsom we ouevnoeaom confluence ones as: a.» n.o~ o.m~ n.o~ o.” GOO n.m e.» n.- n.~u n.m~ o.e o.» m.v n.m~ n.v o.m~ c.e~ n.~ o.- n.a a.- 3 8 T. H a t. B P J o 9 u t 1 u a a... aneeoum n.NN coma n.hm 0.0a n.mn o.m~ 0.¢m coam 0.5" 0.0» wood epuetquxon H coma non n.- o.- n.o~ n.m~ 0.0m non coca n.0u coda satiny em mm mm mm as an bu on on C0 F1 Jeqmnu etdmes 224 azitowazi H O o H eurtemanOL IO 0 N euexooneq 04 1mm 71. n.0u o.o senbedo earqg he >sswue song even“ as pummelev~.o an. a. ...n.=.x aaaam as aaaaaaaaam eaaaaaaao .taa .aaaa «seen4 s a.» 1 n.nm n.~ e.n~ s o.m~ m.~ o.p s o.n~ o.~ e.nm e.m e.om I o.m o.~ o.n~ n.m o.~u H N J a 0 1. u e .l T. O t. d o u b 0 n d a e B b n a B D O CO nausea XUEJ ouch #58 mg: mg: n.~w o.m~ o.m~ o.m~ nomm o.e~ e.v e.e n.0n e.en o.o o.a n.e~ e.- 0.0 0.N~ o.mn o.e~ n.v n.» 0 a .l .d a I. B D. J 0 4 9 e n J u a 0+ asoeoam n.¢n o.HH 0.0N 0.0a O O [- .4 epue IQUJOH H n.e~ 0.0 o.¢m on em mm mm «m on mm mm 0 N D N Jeqmuu etdmes H 225 N zedo; 0 0 eusxooueq o: eartomeag suitemanog ascend I ends 050 anonoam H 0.H 0.H 0.0 H 0.00 H 0.0 0.» 0.00 0.0 0.H N 0.0M N 0.0 0.0 0.0 0.0 0.00 0.0a 0.0 0.0 0.0 0.H 0.0a 0.0 0.> 0.0a 0.0m 0.0a 0.~ 0.” 0.0 0.0 0.0m 0.H 0.» 0.vH 0.00 0.0 0." N 0.0 I 0.00 0.0 0.0a 0.0a 0.0a 0.0 0.0 0.~ 0.0 N 0.0a 0.0 0.~H 0.0m 0.0m 0.0a 0.v I 0.H~ H 0.0 I 0.0 0.0 0.00 0.0a H 0.~ 0.0 I 0.00 0.HH 0.00 0.0 0.0 0.0 0.0 0.0 0.0 I 0.00 0.H 0.0 0.0m 0.h~ 0.0 N 0.0 0.0 I 0.00 0.H 0.0a 0.0g 0.0a 0.0 I 0.~ 0.0 I 0.0a 0.0 0.0a 0.0a 0.00 0.» 1 en mm H H d o. 3 n. V I. I. J a I. T. .a o u 1 I I. o 1. u e I. 1 .3 1 o 1. u e H. v P u I. u o e T. I o a. 1 I. u .l 9 no. I. O 1 fly 0 I. t he 0 O 0 d .d O M O W. m .m o a m o m M d 1. a o a m a. n e 3 men tenuusm sang oeaaa as as2.a-an~.° can a. ...aa=.x mass: .2 auaaaaaaaa neafiwvnoo .bNH canfiu r. 00 O CO Jeqmnn atdmeg 226 eattomeag O O s H e N euttsmano; #:0004 I when as; anemoum N N 0.H H 0.H 0.0 N 0.00 0.0 0.0 0.0 0.00 0.0a 0.0 0.0 0.0 N 0.0a 0.H 0.0a 0.H 0.0 0.0 0.~N 0.0a 0.~ 0.0 0.0 N 0.h I 0.00 0.0 0.0 0.0a 0.00 0.- N 0.0 0.H u 0.0 0.H 0.0a 0.0 0.Hw 0.0 0.00 0.0a I 0.0 0.H H 0.0m I 0.00 0.H 0.0 0.h 0.~N 0.~u H N 0.“ N 0.0 I 0.vw 0.0a 0.0a 0.0 0.0a 0.0a 0.~ 0.~ 0.~ H 0.00 0.0 0.0 N 0.0 0.0 0.00 0.00 0.~ 0.0 0.H 0.H 0.0 I 0.00 0.v 0.0a 0.0 0.0a 0.0a 0.0 0.n 0.H N 0.0 I 0.00 0.0 0.00 0.0 0.0m 0.0a 0.N 0.N 0.0 0.0 0.0a 0.H 0.0 N 0.0 0.» 0.0a 0.00 0.0 0.0 0.0 0.0 0.- I .0obm H 0.¢ 0.0 0.00 0.H~ to n1 I Z M H "H .d 0 ad H V 0 0 I. I. J a I. T. a 0 n d n 1 J I. o n+ u a I. 4a 3 U 0 9 0 n... m U I. 8 D. .u I. 2 o u o e I. 1 o a. 4 I I. u .l 9 a... .l O O 1 .U 0 I. I 9 e a u a .u d a. I e u 9 3 M u 1 p b 0 a u a m m d 1 e a .. .m 4 u e s ham 30:0030 some scene as p-.0nae~.0 .aa a. ..anaa.z spasm «a amsanaanam UOQGMO GOO obNH OHfldafl. 00 N0 H0 00 00 00 $0 00 N0 F! If) C If) xeqmnu etdmeg Thble 127, continued Percentage 01 Heavy Minerals in the O.l49-O.177 mm grade from Saginaw Bay eartoueag engtemanog zsdog euexooueq OIIU9$EI uooxrz senbedo eanA sanbvdo unoxg senbsdo OIIIB$Ofl senate nuts causes £3810 9709152 epuetquaon oztfinv Jeqmnn etdmss 64 227 . 26.5 8.0 10.5 5.0 25.5 65 . 18.0 4.0 . 66 8.5 32.5 9.0 13.0 67 14.0 1.0 43.5 18.0 68 1.5 14.0 . 2.0 3.5 48.5 x Present but rare 17.5 69 Absent Table 128 Percentage of Heavy Minerals in the 0.149-0.l77 mm grade from Saginaw Bay Jeddoo sateen eueqasxedfig 91!I°"I1°V apIBJOIa 091153 °1¥I°19918 eueqdoonetg ea 1201103.; 0114018 911193 sauamfisxg x003 911198 9110190 aslavdv Jeqmun etdmss 228 10 11 0 1.5 2 Present but rare I I 12 Absent continued Table 128, Percentage of Heavy Minerals in the O.149-O.177 mm grade from Saginaw Bay Jeddog sateen eueqasxedfig ozrtouizov epysdoga 071153 OIEI°1n91S eneqdoonstg seizeuow 0919010 611198 sauemfieag aeog atians 6779130 oztzvdv Jeqmnn etduws 13 229 14 15 16 17 18 19 21 22 2.0 23 X 24 Absent Present but rare x O .6 ‘3 :3 0H3 0 'UCt-I GHQ-I :Id :640 ”40‘ 9 s: d gov-I‘d 0200 0 ha ~>a 00 01Gb Hint- H OH. HGO fl .. ' o 9 10" du-t 9. GO 0 0 It 0 a. Saginaw Bay Jeddoo sateen eueqasxedfg °1¥I°VF1°V 99185010 aatlfid 3¢II°1n9$S eueqdoonstg seizeuog 0310019 estate squamfiexg x003 OII¢nH 341°I90 OIEIPdV xeqmnn etdmes 25 230 26 27 28 29 30 . 1.0 31 32 33 34 3.5 35 Absent 1 Present but rare continued y Minerals in the 0.177 mm grade from Table 128, Percentage of He‘v 0.149- Saginaw Bay xeddoo sateen ausqasaeddu °$IIOVEQ°V apiadota 021353 9411019978 eueqdoonetg oatiiuow 0717013 911199 sauemfiexg aoou atizns 6410190 OIIIPdV aaqmnu etdmvs O 36 231 O 37 38 39 41 42 43 5.5 45 46 47 2.0 49 Absent Present but rare continued Table 128, Percentage of Easy y Minerals in the 0.177 mm grade from Saginaw Bay 0.149- Jeddoo sateen eueqasaedfig 9111031197 69196010 001156 azitoxnvzs aueqdoonetg earzsuou 0119019 311103 sauemfisxg noon 9IEIDH 3130190 azisuév xeqmnu etdmss 50 232 51 52 53 54 55 56 59 61 62 63 Absent Present but rare continued Table 128, Percentage of Hegv y Minerals in the 0.149-0.177 mm grade from Saginaw Bay xeddoa eating eueqasxadxg GIIIOUEIOV GPIBdOIG 991156 agrtoxnsas ensqdoonstg eatznuon 9714019 971190 sauemfiexg noon GIIIRH 9110190 6111957 xaqmnn etdmfis 64 65 66 67 68 69 Absent Present but rare I 234 rounding in the heavier metallics suggest severe abrasion by rolling or saltation. This is in contrast to little or no abrasion of quartz or even the heavy minerals of low specific gravity which are prone to transportation by suspension. The concentration of these heavy minerals in varying amounts at different locations throughout the bay may well indicate the hydraulic conditions at a given location. Pettijohn (1933) was able to associate the various physical properties of minerals to the movement of sediments by water. He found that the concentrates of one mineral at one place in contrast to another may be a result of its physical properties, such as: angularity, elongation, and specific gravity. Some minerals which are rounded easily may be transported by rol- ling, and the more angular grains either remain behind to be concentrated or are carried in suspension depending on their 0“ physical properties and given hydraulic conditions. An en tirely different set of transporting conditions may result from a change in the physical environment of the bay, then °°nditions previously adapted to transportation of rounded grains may be altered until they are best suited for movement of angular grains. It is interesting to note in light of this inference, that in comparing the more elongate, somewhat tabular horn- blerAde to the heavier, well-rounded and spherical metallic ”utilise, thattalmost without exception those samples showing a h~3i-gh percentage of hornblende contain a low percentage of me“‘r'ahllic opaques. 235 Leucoxene, in most samples, varies from a slightly altered ilmenite to a proceline-like mineral. The white opaques, excluding leucoxene, represent a group of minerals opaque or nearly so under polarized light, but white in reflected light. Many are stained. Upon iso- lating a few of these minerals some were identified as fluorite. Heavy-mineral separates were made of eight river sands in.an attempt to determine if individual mineral concentrations tiers derived from one particular area. Tables 129 and 130 show the mineral suites from eight rivers entering into Saginaw JBay; It is apparent from this data that no mineral or suite «)1 minerals is unique to any river. Rivers flowing in glacial cirift.are not expected to show any selectivity of mineral suites. Only the Rifle River shows an exceptional accumulation cut one group of minerals, and that of metallic opaques. 236 N eagtomasg eugtnmxnom euexooneq nobwm cansm ad m sebwm acres a nobwm ommwd h hobwm oswm fl asonn< I u c.a n.H~ H c.w o.¢ N o.N n.m~ m.u n.v O.N u m.~ o.a o.m o.vm o.e I c.~ o.h I o.r o.m I H n.m~ o.H o.m~ n.~ I c.~ n.NH n.H m.~ o.~ o.~ o.~ 0.6H n.N 0.0 O.N a O.“ n.on .. o.» u .a Z M H H .d I I. J a F 1 J t. 0 do. u m 0 1 M U x o e I to n I 9 no. 0 0 to 9 C d d 0 I e n u b .o O .u n n d a e a n a s b n e ' euobwm nowooficm scum owssw as -~.olav~.o one a“ magnum“: apnea no ousosoouom emu oases hobum Deswwsm sebum wswsxoaom nobwm wonosswm sebum neom«m Ohdh $98 #flflmflhm n.o c.m m.mm n.m n.s o.w~ c.m 0.0 c.am o.w n.w n.mm n.m m.m m.nm m.m n.w o.cm o.o m.» m.mm n.~ m.m m.mm O a nu .l d o O t 1 e P n a o q 1 T. nu 9 9 P n J p u a a 1 ‘#QCJG a m h c m m (J 4 satdmns duo: 237 xeddoa eaten” H eueqassedfin amztoutmov aptsdogq nobam cansm :4 a use“: isswmsm nob“: marsh c scram mn«d>onem uo>as one“: a copes macaques neewm oswm m hobwm noowwm asooa< I ones can vsoaoum I I I c.~ I N c.~ I I I I I I H n.a n.m N H I I I I I N c.~ N I N I I I I N o.n N I N I I I I N n.m I c.m I I I I I m.H m.m N c.¢ I I u I H H 6.9 H c.v N I N I I I o.v I c.m .d S 9. W n. 8 fl. 8 Au .A 1.. T. 0 I 9 0 n U 1 e e n o 1 o 1 I I. n n m 1 I x. I. o 1 J 0 I 1 .l t. a .0 o t. 1 a .d a 1 T. d 1 a 1 a t. u. a 9 1 n 3 a u w e a u 1 B ahebud cocooaom Beau even» a! -~.olovH.o as» a“ canyon“: abaom «o ouaozeouom and onafia azrzvdv c) I: m k: c: m m setdmns <2 ROUN DNESS AND SPHERIC I TY Grains from the light mineral fraction in the 0.177 mm (-) range were mounted in Canada balsam for roundness and sphericity determinations. The grains of each sample were projected by conventional methods onto a sheet of paper and the outlines of 50 were traced. Riley's method (1941) for determining sphericity and Wadell's method (1932) for de- termining roundness were used. Riley's formula is defined as the diameter of the largest inscribed circle that can be drawn inside the grain outline, divided by the diameter of the smallest circumscribed circle, where the square root of the product is the degree of a'Pllericity of the grain. This may be expressed mathematically as: S:./i/C where: izradius of maximum inscribed circle, C: radius of smallest circumscribed circle. The student using this or any of the methods which l.°‘l‘lire measurement of projected grains should be aware that true three-dimensional sphericity cannot be measured in this 238 239 manner, and this provides at best only a mathematical estimate of sphericity. Wadell's formula, which measures the angularity of the icormers of a sand grain, is expressed as the arithmetic average (x! the radii of curvature of its individual corners, divided b3r the maximum inscribed circle. As the roundness is increased, tJrus the radius of curvature of the corners is also increased. This may be expressed mathematically as: Pzzl‘ZD B where: B = radius of maximum inscribed circle r = radius of curvature of individual.corncrs n = number of corners measured Unless the grains are measured directly from the PPOJections, great care should be taken in tracing the out- line so as not to accentuate the angularity or roundness of the individual corners. Roundness and sphericity are factors commonly related t° 'tlle movement of sedimentary particles, and are often used a“ an aid in determining environmental conditions. Much information on roundness and sphericity has been published, but few conclusions have evolved. Russell (1939) discussed roun4ixnega and sphericity with regard to sorting, grain size, and 83nd movement, shedding some light on the misinterpre- t 0 “ti on; of their association. Further work by PettiJOhn 240 and Lundahl (1943) and Twenhofel (1945) support Russell's theories on abrasion and sediment movement. Average round- ness and sphericity of s sediment may vary as a result of any single factor or combination of factors. Each will be (liscussed in light of these variables. A graphic presentation of roundness and sphericity :frequency.is shown in Tables 131 to 146. The modal class is: the roundness determinations is 0.500 in most samples, inhereas in sphericity the modal class is in the range of 0.800 to 0.850. 241 hawowuognm concussed hwwomuennm muosucsod w w.mu v u. 9 Au 9 n. v w.nv a no r r.”r r w... . H. w u.”v v 0 9 no 9 0 n. 0 as 0 Au 0 nu 0 0 AU 0 no.0 0 c TL cum II. lllowo 8 II .Ilomu n.’ II rinowh a ll (Ion Ill leoo M. i a sonasz sunfism a sonasz ommasm hauufiusmam nsosvsscd hvwowuoznm concussed O I O O I O 0 I s D O s O O I 0 I 9 O O O I I o o O 6 no.8 L I. 9 as 9 L o. 9 f as 6 as 8 IL L a. 9 y. 9 t 8 0 as 0 oz 0 o..u 9 0 nv 0 no 0 0 .1 0 .w 0 ns 0 0 AU 0 Ii N... m 0&7 Tl. oh 9 YI‘L o _ _ . . N soaasz sadism H hooasz oumlsm Zouhamudamma wsmoudmmmm Q24 mmflzgzaox ho wZ9~a~ddf~m 2;; wwxzazdjm L4). litigfimwd o2 0:: 247 hewofluo;;m mm::w;: f s e s s e . e R. d J. I» 11- HJ NJ H: L Al. I.— ll. AI” 6 (.U C. U n... 0 n... 0 In H 0 \IV I n 0 CLLLF. O O O O O I I I n o O s 0 6 8 R .L .L 9 9 c. L U l . .: 0., 0 C. 0 (a 0 L. U C. U 0 . l U 10 98° 08' zuwuwuesz mmccnmmofi I 1 I O s e s s s s I. I. 9 9 C . L 9 .u. L... .k 02 0 n... H U U U .U ofincuooxod v M .LI LI'I ON hocssz $17.3...n hawosnosam condensed afinuneoxad I m. m w I m m _ _ _ h L a wN hoeusz .oTaustm zgw&_:~“vnmha whauwfiuan Lz4 um” canes hm hopasz mamasm mwmzazmnx as w2 mmmzozaom .ON ~52... _ _ _ _ _ W om¢ .owt O p Q: '31“! 00¢. o m e, SSBNONOOB con. ,05. can. Own. 9%. room. own. 262 ROUNDNBSS AND MEDIAN DIAMETER —- Inasmuch as the depth of water and median diameter of the sand are generally related, there is an interrelationship involving depth of water, median diameter, and roundness. The fine sediments from areas of deep water in the western half of the bay show a noticeable lack of roundness. The sediments in the deep water east of Charity Island show a considerable variation in grain roundness from one sample to another. Figure 21 indicates that there is no linear correlation between roundness and median diameter, although those grains with a roundness of 0.500 and above occur in the sand-size sediment. It is generally agreed that little abrasive action takes place on very fine particles in deep water where Blower currents are prevalent. Many writers believe that Solution is as important as abrasion in the process of rounding of particles of sand size and smaller. ROUNDNESS AND SORTING -- The sediments of Saginaw Bfiy show little or no relationship between roundness and aOrting (Fig. 22). One might exPect to find a general area correlation in which the finer, poorly rounded sediments fPom deep water have poor sorting. This holds true for atune samples in Saginaw Day, but it has been shown that t'here are many exceptions where sorting is more a factor of currents than depth. 263 0 N 0.0 0.0 3.2: :3 o... m urmzda. 250m: 0.m 0d 0.. 0.7 A fl mwkmzfio Zions. m> mmmzoznom ._N «.53... _ Jone ll 00¢ I12... 1 M 08.». 1|. 00¢N O :. Illoomd. own. 0mm. o¢n. mm. 264 ozimom 05. 00.. 02.. 000. con. 00... 80F 00a. 00.. __fl__ _Ifi A 02.58 0, mmmzoznom .3 «so: _ _ AI; _ II 05¢ Ont 03V '3A N008 IIQO II, S 80.5 ‘00». gm. \ 265 BOUNDNESS AND SKEWNESS -— There is no linear cor- relation between roundness and skewness. Figure 23 shows that the sediments which possess high roundness tend to be skewed more to the fine side. 266 00m; 000; com. 000. mmmzzmxm no. 004. cow. OONI. 00¢:I mmngmxm m> mmmzoznom .nm 23: ____ _ _ _ 00¢ .00¢ 05¢ 00¢ 00¢ 00% n!@ 0N0 ,0¢0 .009 OMQ own ssauounoa 'BAV SPHERIC I TY High sphericity is recorded in the sediments off Point Lookout near the north shore. This zone of high sphericity may be extended southeast across the bay in the vicinity of Charity Island to Sand Point and then along the southern shore. Other areas of sediment with high sphericity occur with less regularity throughout the bay. Average sphericity data are shown in Table 147. Average sphericity distribution is shown on Plate 7. SPHERICITY AND DEPTH OF WATER -— Sand particles Vi th high sphericity are more common in shallow portions 0f the bay. High sphericity values are noted in shallow wa ter west of Charity Island, and on the south shore from Sand Point to Hat Point. Values somewhat higher than average are found close to the south shore west of Sand POint. Low sphericity values are recorded from samples in the narrow trench which parallels the south shore. High sphericity, comparable to that along the south shore, follows the shallow water between the north shore and the glacial Saginaw River channel. In deep water at the Open end of the bay, high sphericity is inconsistent “- til the highs normally associated with shallow water. Values are fairly equal in the deep water of the western half of the bay and no linear trend is apparent. 267 «o O It’d- ‘Ech‘éiz‘hj" Scale “ Thousands of Fee! SAGINAW BAY AVERAGE SPHERICITY DISTRIBUTION ISOPLETH INTERVAL. .OIO Units L PLATE 7 269 Figure 24 shows Sphericity as a function of depth. bJo linear correlation is apparent, therefore, it is felt 'that the distribution of sediments according to shape is EL result of some factor other than that of depth alone. SPHERIQITY AND MEDIAN DIAMETER —- Since there is a general areal relationship between depth and sphericity and depth and median diameter, one might also expect a general areal relationship to exist between sphericity and 1nedian diameter. Sphericity, like roundness, is not a ;product of abrasion in the fine-grained sediments, or at least not so in one sedimentary cycle. In the areas of sand concentration, sphericity for the same reason as round— Iless might be expected to increase; however, coarser materials, izicluving granules, pebbles, and cobbles are capable of ifxfacturing the smaller grains. This fracturing may bring aJaout a decrease in sphericity. Figure 25 shows sphericity plotted as a function of nHadian diameter. No linear correlation is apparent. §£NERICITY AND SORTINQ’-— There is no relationship b*etween the degree of sorting of a sediment and its sphericity ill Saginaw Bay. This is verified in figure 26 in which WPllericity is plotted as a function of sorting. Neverthe- lesa, it is thought that grains are transported and distributed according to their shape as a result of so-called selective tr an sportati on . 270 mm mwh<3 uo Ihamc 00 no 00 ms 0h 00 00 mm 00 we 0? mm on ____4 fi_ ”BESS do Ipamo m> >.:0_mmxam .¢N 032... _ _ _ _ _ 0 .h. ON 5.. ’SAV on b. 3 Ir. 0 In N. ‘AlIDIH3HdS 00h CNN 00». 00H 000. 0.0. 0mm. 271 2.2: 2: 55243 24.3: OK 0.0 06 0.0 0.n 0.,N 0. _ 0 0,...- _ _ — _ _ u - «5.225 2585. .4 Euauxam .2 .33... 4 CNN. l E}, cl I :2. 3. 5. BAV ALISIUZRJS .' I: . 00h. ... 00h .. 0.0. . 36. 272 000. . 00h. 000. 00m. 00¢. 00m. 00.0.. 00.. DB. _ _ _ _ _ _ _ _ _ _ _ _ _ _ 02.5.00 m> >20medm ll .mm 9.53“. . . IJ 0F. CNN On». .03.. 00h. 00>. 0h». 00m 005. 0.0. 80. 000. 'BAV AllDlHBHdS 273 SPIIERICITY AND SKflNESS -- There is no linear cor- relation between sphericity and skewness as shown in figure 27. Those grains which are highly spherical tend to be so-ewhat less skewed than those having less sphericity. SPHERICITY AND ROUNDNESS -- There is no apparent relationship between roundness and sphericity (Fig. 28), although a slight linear trend can be seen along the north and south shores in areas of supposed constant currents and greater sand accumulation (Pls. 0 and 7). Russell (1937) points out that grains showing a high degree of roundness and sphericity might be expected to Occur in areas of greater concentrations of sand-size grains. 0n the other hand, should these same areas contain larger granules or pebbles along with sand-size grains there is a likelihood that the smaller grains may be fractured if strong wave or current action should cause the sediments to be agitated. This results in factors of lower roundness and Sphericity in the smaller grains. Russell does not Propose a high degree of rounding by abrasion even in the areas of sand accumulation. Heugh (1042), in his study of the sediments of Cape 00d Bay, found no relationship between sphericity and median diameter, and roundness and sphericity. He found a .light correlation with depth and sphericity and round- n°" 8 and depth. 274 wmwz3mxm 00. 00m._ 000.. 000. 000. 00¢. 00m. 000. 00Nr. 00¢.! _______ mmmzauxm 2 >tomedm Na .53... _ _ 02.. III ouh g N 0 ID . F. AUDIUBHdS '3/W 0 3D h L 2.4.. I. 00h. ll 00H l 000. III 0.0. 0mm. 275 0.0. 000. Ohm. mmmzozsom ohm. 0mm. .w>< oi 0&0 9% mmwzozaom _ _ m> >...0_mm...n.m .mm 0.30.... A _ _ 0.». 0m... | 8 N '3AV 7.? F. 8 3". AllDIHBHdS 0 IE, 02.. 00... 00h 000. 0.0. N0. 276 CONCLUSIONS —- At best only very general conclusions can be established with regard to roundness and sphericity in Saginaw Bay. The average roundness and sphericity distri— bution shown on Plates 6 and 7 indicates a somewhat linear trend corresponding to known current patterns. The writer does not believe that current alone can be the main factor in producing roundness or sphericity in any grain. This same fact has been suggested by many students studying sediments occurring under similar environments. Russell (1030), Pettijohn and Lundahl (1043), Twenhofel (1945), and Real and Shepard (1956) agree that it is very improbable that abrasion has much effect on rounding of grains of sand-size or smaller. That if rounding does occur, it takes place in areas of sand concentration. Twenhofel Etetes that traction is the main agent, if not the sole agent in abrasion of sand grains. The grains of less than One—quarter millimeter in diameter are rounded very little 011 sea or lake shores, whereas those grains larger than °ne~ha1f millimeter appear to be rounded fairly easily during traction transportation as judged by the abundance of rounded grains of this dimension. High roundness and Bph‘Eéricity values in Saginaw Bay are too erratic to state any such specific conclusions. Furthermore, it can be Said with reasonable certainty that solution is an equally lmDortant factor in producing roundness and sphericity in 301119 mineral grains . 277 Kuenen (1950) and Russell (1039) cited evidence for believing that grains with higher roundness and sphericity ‘values are more easily transported by rolling in contrast to the less spherical and less round grains which tend to be transported more easily in suspension. Morris (1957), in relating roundness and sphericity with fluid velocity, found that in high fluid velocity, angular grains move faster and farther than those rounded because of local turbulence set up around the angular grains. This local turbulence impedes rapid settling of particles. In low fluid velocities, rounded grains move faster and farther than angular grains because of their ability to roll. There is no evidence to prove which is the dominant factor in carrying sediments in Saginaw Bay. It may be said with reasonable certainty that cur- rents and wave action in Saginaw Bay are strong enough to move sediments, regardless of shape, by rolling, saltation, and suspension. Any local distribution which shows some uniformity is probably a result of selective transportation "hi ch, because of other varying factors, does not carry thI'oughout the bay. The Saginaw Bay sands are of glacial origin, the ma‘toerials of which are derived from a great variety of I"’CBks dating to Precambrian. Those sediments already dePosited and those presently being deposited in the bay have survived one or more sedimentary cycles. Therefore, 278 a considerable range in roundness and sphericity may exist ixi the grains before they are acted upon by the mechanical processes within the bay. Twenhofel (1945) in support of his conclusions on ironinding by recent wave and current action cites this history of a single sand: "Most sands on most beaches and in most dunes have been successively transported by wind and water. This is illustrated by sands collected in dunes on Camp McCoy in western Wisconsin. The sands for these dunes were brought to them from the flood plain of the LaCrosse River to the west. The river obtained the sands from Cambrian sandstone across whose outcrops the river flows, from the St. Peter sandstones which once overlay the region, and from outwash sands of the Wisconsin glacier. Grains in Cambrian and St. Peter sandstones are well rounded in many beds. The St. Peter sands seem best interpreted as water de- posited after reworking sands of dunes, the dunes having been formed in early Ordovician time following emergence of the Prairie du Chien limestone. The dunes proba— bly obtained the sands from Cambrian sand- stones. The outwash sands were derived from all formations over which the glacier moved from the oldest system of rocks to the Pleistocene. Ultimately many of the sands were derived from the Precambrian formation. With this complexity of history, of what value is any expression of roundness ac- complished during the last tranSportation?" Inasmuch as most of the material in the bay is sand or Smaller, it is entirely possible that little or no cllallge has taken place in the sediments since the formation 0f glacial Lake Saginaw. Variations in selective roundness and sphericity (1' . . . . . 1E3tr1but10n are due to a combinat1on of select1ve transport, 279 current velocity, bottom topography, quantity of sediment, river influence, depth of water, and grain size. This sEelcctive distribution is not a result of abrasion as a function of length of time and intensity of wave and current action on the sediments in Saginaw Bay. AC ID SOLUBLES Two grams of sample, dried at room temperature, were placed in an evaporating dish. Acid solubles were removed by a solution of .1N HCl, titrated to a pH of approximately 4.4. Methyl purple was used as the pH indicator. After approximately 24 hours the sediment was washed with distilled water, decanted, and dried. The residue was assumed to be the acid insolubles, which included organic carbon. It was h0ped that by using this method the carbonates could be easily removed. Certain minerals other than calcite and dolomite are affected somewhat by the HCl solution, but the sand of Saginaw Bay is predominantly quartz and the other minerals occur in Hue}: small quantities that very little solution is likely to take place. Several other methods for determining acid soluble °°ntent were considered, but in most instances the procedures were too lengthy and the reliability of the results did not justify the time they required. Acid solubles are in all the samples. They range in amounts from 0.062 per cent in Sample 24 to 3.680 per cent in Sample 14. The latter amount is not in context with the 280 281 average of 1he other data and the sample from which the results were obtained may not be valid. The acid solubles or carbon- ates appear to be derived largely from detrital calcite, dolomite and shell fragments. Nearly half of the 61 samples contain less than 0.400 per cent acid solubles and 85 per cent-contain less than 1.000 per cent. There appears to be no uniform distribution from which definiteconclusions can be expressed relating the acid solu- bles to current patterns, although it may be seen by the iso- pleth arrangement on Plate 8 that high percentages occur in an elongate belt close to the shore in line with the pre- vail ing currents . These areas of high acid soluble percentage are located on the flanks of the glacial Saginaw River channel in the Western half of the hey at locations 7, l4, 17, 25, and 38. similar high amounts are found close to the south shore at location 21, 31, and 41. Acid soluble data are shown in Table 148. ACID SOLUBLES AND MEDIAN DIAMETER -- No linear c01~relation results when acid solubles are plotted against median grain diameter (Fig. 29). Samples taken from the west end of the bay in areas of generally fine—grained sedi- ments show relatively high acid soluble content. This is noticeably so in Samples 7, 16, 17, 18, and 27 which outline the trench of fine sediments extending northeast from the mouth of the Saginaw River. Samples 14, 31, 41, anr‘. 67, 282 O 0 III 1 I)! l O I I!“ SAGINAW BAY ACID SOLUBLE DISTRIBUTION ISOPLETH INTERVAL .200 Percent PLATE 8 283 Table 148 ORGANIC-ACID SOLUBLE PERCENTAGES weight of Acid Acid Sample Sample Soluble Soluble Organic Organic Number (Grams) Loss Percent Loss Percent 1 5.0153 0.0134 0.263 0-0522 1.041 2 5.0124 0.0225 0.449 0.0686 1.369 3 5.0004 0.0236 0.472 0.0531 1.062 5 5.0017 0.0184 0.368 0.0201 0.402 6 5.0000 0.6196 0.392' 0.0148 0.296 7 5.0050 0.0510 1.019 0.2402 4.799 8 5.0010 0.0151 0.302 0.0182 0.364 9 5.0000 0.0106 0.212 0.0800 1.600 10 5.0143 0.0299 0.596 0.0500 0.997 11 5.0043 0.0216 0.432 0.0410 0.819 12 5.0008 0.0264 0.528 0.0304 0.608 13 5.0070 0.0147 0.294 0.0484 0.967 14 5.0000 0.1842 3.684 0.3936 7.872 15 5.0037 0.0248 0.496 0.0221 0.442 16 5.0155 0.0429 0.855 0.2491 4.967 17 6.6007 0.0932. 1.864 0.1010 3.020 18 5.0000 0.0632 1.264 0.0398 0.796 19 5.0133 0.0226 0.451 0.0395 0.788 21 5.0000 0.0970 1.940 0.0650 1.300 22 5.0009 0.0276 0.540 0.0399 0.798 23 5.0019 0.0183 0.366 0.0177 0.354 24 5.0007 0.0031 0.062 0.0026 0.452 25 5.0005 0.0599 1.198 0.0308 0.616 :84 Table 148 ORGANIC-ACID SOLUBLE PRICINIIGBS, continued Height of Acid Acid Sample Sample Soluble Soluble Organic Organic Rasher (Grams) Lose. Percent Lose Percent 26 5.0007 0.0599 0.654 0.0687 1.374 27 5.0007 0.0327 0.826 0.3180 6.359 28 5.0000 0.0413 0.078 0.0260 0.520 29 5.0012 0.0039 0.644 0.0370 0.740 30 5.0006 0.0322 0.570 0.0145 0.290 31 5.0020 0.0285 1.555 0.0862 1.723 32 5.0000 0.0778 0.224 0.0119 0.238 33 5.0007 0.0112 0.164 0.0199 0.398 34 5.0012 0.0082 0.396 0.0242 0.484 35 5.0010 0.0198 0.216 0.0185 0.370 36 5.0008 0.0108 0.334 0.0166 0.332 37 5.0000 0.0167 0.400 0.0255 0.510 38 5.0007 0.0200 1.196 0.0722 1.444 39 6.0008 0.0598 0.124 0.0101 0.202 41 5.0010 0.0710 1.420 0.1653 3.306 42 5.0000 0.0080 0.160 0.0093 0.186 43 5.0000 0.0075 0.150 0.0243 0.486 45 5.0012 0.0231 0.462 0.0085 0.170 46 5.0000 0.0271 0.542 0.1167 2.334 47 5.0007 0.0263 0.526 0.0160 0.320 49 5.0002 0.0397 0.079 0.0445 0.890 50 5.0002 0.0333 0.606 0.0356 0.712 51 5.0000 0.0214 0.428 0.0178 0.356 285 Table 148 ORGANIC-ACID SOLUBLE PERCENTAGES, continued Weight of Acid Acid Sample Sample Soluble Soluble Organic Organic Number (Grams) Loss Percent Loss Percent 52 5.0000 0.0148 0.296 0.0095 0.102 53 5.0001 0.0081 0.162 0.0051 0.102 54 5.0001 0.0082 0.164 0.0422 0.844 55 5.0000 0.0194 0.387 0.0333 0.666 56 5.0002 0.0217 0.434 0.0270 0.540 59 5.0000 0.0336 0.672 0.0058 0.116 61 5.0000 0.0472 0.944 0.0098 0.196 62 4.9998 0.0160 0.328 0.0674 1.348 63 5.0000 0.0192 0.284 0.0097 0.194 64 5.0002 0.0413 0.826 0.0100 0.200 65 5.0002 0.0432 0.864 0.0072 0.144 65 5.0000 0.0229 0.458 0.0085 0.170 67 5.0005 0.0473 0.946 0.0042 0.084 68 5.0001 0.0205 0.410 0.0106 0.212 69 5.0001 0.015 0.302 0.0171 0.342 286 952: £3 mmhuzaa 24.3.2 S as as o... on as o._ Sm .______l____:__._ .. 1.... on e eeee e e“ 1|lO¢.O .. .... . 183. $5.245 24.32 2 3.638 904 . . . . m . a . 11 . mm e3 7.. . 000% O C O m . . . 1109 m . 118.21... w m. . 119... m 3 . 118.. 118.. .11oo.~ cud 287 high in acid solubles, possess very small median diameter. However, if one considers all 61 samples taken from the bay, it can be readily seen that the establishment of acid solu- bles as a function of median diameter is more of an exception than a rule. Any correlation that exists between fine—grained sedi- ments and high acid soluble content may be attributed to fine shell fragments accumulating in areas of deep or restricted water. A high that occurs in the coarse-grained sediments near Katechay Island is associated with selective transpor- tation of certain sizes containing shell fragments or detrital carbonates. Caldwell (1940) found a general increase in carbonates with a decrease in grain size in the sediments from Barataria Bay, Louisiana. Carbonate percentage in Barataria Bay ranges from approximately 2.0 to nearly 90.0 per cent. Here shell fragments account for most of the carbonate. In contrast to what has been said, Shukri and Higazy (1944) noticed an increase in carbonates in the Red Sea with an increase in grain size, but they did not discuss their observation. Bough (1940) draws no comparison between carbonates and grain size in Buzzards Bay. He notes only a slight increase in carbonate with depth of sediments. He attributed this lack of carbonate to solution taking place over a con— siderable period of time. This same effect has been noted in many deep water deposits. 288 The sediments at locations 21, 25, and 01 on the south- east side of the bay, and locations 38 and 65 along the north- west shore are coarse-grained and contain substantially high acid soluble content. These samples contain a few shell fragments which may easily account for the amount of acid solubles. The marked variation in acid solubles in a given grain size may be attributed to two possible factors. First, it may be established that in areas of coarse material the shell fragments are crushed and broken in part by wave action. The small pieces are subsequently carried in suspension or by saltation to areas of accumulation in quiet water, which may be either deep water or shallow protected areas. The somewhat larger fragments, which are not easily moved, ac- cumulate in certain localities as a result of selective trans- portation. A lack of any appreciable amount of acid solubles in a given grain size indicates a lack of source of shell fragments or an agent suitable of carrying the material containing the acid solubles to a specific locality. A second source of soluble materials, as shown in Samples 21 and 38, (median diameters of 1.690 and 0.320 mm respectively) can be explained by weathering of limestone outcrop or boulders along some of the shoreline. Sample 21 was taken adjacent to Katechay Island and Stony Island which are composed of Bayport limestone (Fig. 4). Much of the coarse sand and pebbles are derived from the weathered 289 limestone on these islands or from rocky accumulations along the shore. The sands in Sample 38 are considerably finer, but they also contain a few small pebbles and rock fragments which might be derived from Point Lookout Bayport limestone. Due cannot exclude the possibility that the great flecks of wildfowl which inhabit the islands on the south- east side of the bay carry considerable quantities of shell animals into these waters. ACID SOLUBLES AND DEPTH OF WATER -— It has been shown in the discussion up to this point that a general relationship exists between grain-size and acid—soluble con- tent in the sediments, and on this basis one might expect to find some correlation between depth of water and acid solu- bles. Although no linear correlation can be established, a concentration of points in the shallow depths and low acid soluble range are shown by figure 30. ACID SOLUBLES AND ORGANIC CARBON —- It is generally accepted that organic carbon is more abundant in the fine- grained sediments. In Saginaw Bay these finengrained sediments show for the most part a high acid soluble content. Figure 31 shows a slight relationship between sediments containing low acid soluble content and low organic carbon. Track (1942) found no correlation between carbonates and organic carbon in deep sea sediments. In spite of the fact that the relation between organic (:arbon and acid solubles is not always present under all 290 om mm m m .23 no on av Items 9. on on 2 ON 2.23 do :EH. 2 8.533 on 23E _ 0.04 _ _ Jomd J 0.5 .I. owe 86 I18. I ON; I om. ll 02 I1 oo.~ l ONeN 39V1N3383d 3180103 OIOV 91 mudhzwomua 0.240m0 0.¢ 0.n 5328 2242.0 2. 8.538 904 ._m .33... . . HI 0N0 ....loe.o . 00.0 I... 00.. III 0N. ll 0¢.. I 00.. Ill 00.. ll 00d 1' CNN 39V1N3383d 3180108 OIDV 292 circumstances, it is interesting to note that a slight cor- relation generally exists between grain-size, depth of water, acid solubles, and organic carbon. This association is a reflection of the physical environment of the bay, and when considered in light of recent sedimentary deposition it might be utilized in the interpretation of the physical environments at the time of deposition of ancient sediments. ACID SULUBLES AND SORTING -- The relationship between sorting and acid solubles is shown by figure 32. The relation between grain-size, sorting, and acid solubles is only slightly apparent. However, low acid soluble percentage usually is associated with good sorting and the high acid soluble per- centage is to some extent more prominent in the more poorly sorted sediments. This agrees with the correlation of fine sediments, which generally are poorly sorted and have high ac id soluble content. ACID SOLUBLES AND SKEWNESS -- Figure 33 shows the relationship between acid solubles and skewness. For the most part sediments which show nearly zero skewness or are Bkewed to the fine side of the curve contain less than 0.800 Per cent acid solubles. Gnerally those skewed far to the °°&rse side contain more than 0.800 per cent acid solubles. ACID SOLUBLES AND CURRENTS -- Only general relation- ships between acid solubles and grain-size, depth, and sorting are established. The amount and source of acid soluble 293 0N0 0.10 , 00.0 00.0 ON. Ct. 00. . 00. . oz.emom 93 com. 00». com. com. ooc. com. com. 00: ooo. _ _ _ _ _ . _. _ _ _ _ T _. .ozEEm .2. mwnmaoom 904 . . 11 .NM 3.3.... . IL . ll. 00. N OWN 39V1N33838 3180105 OIDV 294 mmmzzuxm 3. 00“.. 000.. 000. 000. 00¢. 00m. 000. 00¢.! mmmzmem m) mmnmanom 0.04 . . . . .mm 0.30.... . _ . 8.0 1] one l1 8.0 Load l1 8. _ Lou. _ J 0e. . l om. _ .1 8.. 1|..oo.~ Ill CNN 39V1N30838 3180108 OIOV 295 material appears to be the greatest factor in determining its distribution; although, some acid soluble materials are probably sorted locally according to the physical properties and environment of the sediment in which they exist. From the data available, current patterns cannot be established upon the acid soluble content of the sediment. ORGAN IC CARBON After the insoluble residue from the two gram sample was weighed, the evaporating dish containing the residue was placed in a muffle furnace and fired slowly at 650.0. Upon cooling, the sample was weighed again to determine the amount 01 organic carbon which had been ignited. From this infer- nation, the percentage of organic carbon was calculated and plotted on an isopleth map (P1. 9). Data of organic carbon percentages are shown in Table 148. more is no agreement as to the best method to de- termine tho amount of organic carbon in sediments. Track (1939), for example, states that the reliability of the data ‘Gcreases with the increase in calcium carbonate in the sedi- lent. Clay content may be another source of error when igniting 4 fine sediment. Certain clays lose their lattice water at Iltdoratoly low temperatures, and if clays are present in I‘m-go amounts this error may be considerable. Ignition seems to be the most practical method, in light of the amount of organic content present in most of the samples, to determine the amount of organic carbon present “incorthe acid solubles have been previously removed. Several ‘ethods of extraction were investigated, including those discussed by Robinson (1927), Alexander and Byers (1932), 296 ‘Wflfl ‘uo... 297 SAGINAW BAY ORGANIC DISTRIBUTION ISOPLETH INTERVAL .200 Percent PLATE 9 298 Schollonbergor (104s) and Valkloy (1947). But most .1 the procedures were too lengthy to justify their accuracy. A great range in organic carbon percentage in the Saginaw Bay sediments produces marked patterns in areas of concentration. Percentages range from 0.084 at location 67 to 7.872 at location 14. Approximately 60 per cent of the sediments contain less than 0.500 per cent organic carbon, and 25 per cent between 0.500 and 1.000 per cent. Nearly 10 per cent possess 3.000 to 8.000 per cent organic carbon. The latter figures are considered substantial even for deep sea sediments. Griponborg (1939) reported between 3 and 10 per cent organic content in the Baltic Sea sediments. He considered this a high ratio. Kuenon (1950) recorded as little as one per cent carbon 1000 km off shore, increasing to two and one half per cent within 100 to 200 km from shore. In confined bodies of water, such as fiords, the organic content may be about 35 per cent. It is generally agreed that organic carbon is derived largely from plant and animal life in the water, but there is a definite lack of plant growth in Saginaw Bay. The normal turbulence of the water tends to hinder any organic concentration. Hooper (1958), however, has pointed out that the organic content probably stems from the small floating type of planktonic plant life rather than from the common weeds known to most of us. 299 Sediments containing a high percentage of organic carbon are found at location 46 south of the Tawas hook and location 38 near Point Lookout. An area of generally high percentage of organic content is circumscribed by locations 7, 16, 17, 26, and 27. Sample 14, which contains abnormally high percentages of acid solubles, has an un- usually high amount of organic carbon. Sediments close to the south shore, including locations 1, 2, and 3 in the southeast corner of the bay and location 9 near Fish Point, contain a high percentage of carbonaceous material. Samples 21 and 31 taken in the vicinity of Katechay Island and Sample 41 taken near Oak Point are high in organic carbon. Samples 31 and 41 lie in what might be termed areas of current shadows. In contrast to Sample 14 which contains 7.872 per cent organic carbon, is Sample 13 on one side containing 0.967 per cent carbon; and Sample 15 on the other side containing 0.442 per cent carbon (Pl. 9). The sediment of Sample 14 consists of silty organic material and has a median diameter of 0.142 mm. The sediments of Samples 13 and 15 are clean, medium sands of 0.325 and 0.219 mm diameters respectively. This abnormal concentration of organic carbon is explained by selective deposition by currents which may be deflected somewhat at a point where the Saginaw River enters the bay. Sample 5 does not show a high percentage 300 of organic carbon because of its location in shallow water in the direct path of currents on the west end of the bay. It is possible that there is more of a tendency for organic matter to be removed from the sediments in the face of strong currents. Sample 14 was taken from 20 to 25 feet of water at the edge of the glacial Saginaw River trench. ORGANIC CARBON AND MEDIAN DIAMETER —— High organic carbon content is usually associated with fine-grained sedi— ments. Most organic carbon has nearly the same specific gravity as water, thus undisturbed water is necessary for complete settling out. Quiet water environment, of course, is a prerequisite for fine-grained sediment accumulation. A correlation between median diameter and organic carbon is shown in figure 34. Data show that the preponder- ance of the sediments are low in organic carbon, and those which have high percentages are fine to very fine sediments. Kuenen (1950) established a relationship between fine-grained deposits and high organic content. He explain- ed that the fine-grained sediments tend to enclose the organic matter and protect it against oxidation to a greater degree than would be possible in coarse-grained sediments. The coarse sands offer greater permeability which allows water to circulate freely, introducing fresh oxygen into the deposit. The organic matter is more easily decomposed and carried away. 301 Trask, et a1, (1940) expressed a relationship between texture and organic content in which both were directly re- lated to movement of water. In areas of strong currents, coarse materials were generally present and the organic content very low. In contrast, in areas of weak currents typical of protected areas or in waters of considerable depth the sediments were generally fine-grained and the organic content high. The gross relationship of organic carbon, currents, and depth of water can be extended to Saginaw Bay with few exceptions. Particularly is this true of locations 7, 16, 17 and 27 where somewhat quieter water allows fine-grained sediments to settle. Samples 31 and 41 represent fine- grained sediments deposited in quiet water areas not af- fected by strong currents. It appears that the Sand Point projection deflects the main body of current away from shore, thus allowing relatively quiet water deposition at location 41 (See discussion on median diameter, p. 171). Sample 38, taken from moderately deep water below Point Lookout, consists of medium grains and contains a moderately high amount of organic carbon. Sample 39, also protected from longshore currents by Point Lookout, falls into the same grain size range as Sample 38, but it is practically void of organic carbon. Numerous authors have shown relationships between Organic carbon and grain size. Krumbein and Caldwell (1939) 302 3.2: 3. 3524.0 24.3: , o... , om om oé o.m o.~ 0.. o._1 _ _ _ _ A. _ _ _._....._........_ u.” .... [8.0 .. - I|.00.. mmhuzqa 24.9.2 2. .hzmhzou 0.24.3.0 . 11.3.. .wn v.33... Iloo.~ I110n.~ . 11.0% load Iloo.w . . ||,00.m llood ll,oo.~. 00.. 1N31NOS SINVS 8 0 39V1N 33 8 3d 303 in their analysis of the sediments of Barataria Bay concluded, '...that both carbon content and grain size are functions of the quietness of the water, inasmuch as the finer sediments and the organic matter are deposited under similar conditions.“ Hough (1940) found about 2.0 per cent organic carbon in the fine-grained sediments in Buzzards Bay, Massachusetts. This relationship is expected to hold true more consistently in larger, deeper bodies of water. The relationship between particle size and organic carbon has been established in many lakes throughout the country. The organic content is relatively low in the central portion of the bay, extending from a line a few miles west of Charity Island eastward to the entrance of Lake Huron. This broad expanse of water, ranging from a few feet to 100 feet deep, comprises an area free of littoral currents. Very little organic carbon has accumulated in the sands, thus the carbon which has concentrated in other parts of the bay stands out. ORGANIC CARBON AND DEPTH OF WATER -— It is easily understood that if there is a relationship between organic carbon and grain size, then depth of water is also a factor. Figure 35 indicates that those sediments which contain low percentages of organic carbon are more abundant in shallow water. It has been previously suggested that the sediments in Saginaw Bay are more of a function of current than depth, and little correlation between depth and organic content mmhd.’ do Ihauo 304 mm 8 2. 2. no om on on me 0.. on on 3 on m. o. m o ____.._ _ e _ _. a .. ..._....u ... . . . . . . ..n Leno . . . u . 00.. 522. .6 Emma 2. ezmezoo 2242.0 . . 8.. .00 030.... 0 83M . m lemma 3 O . anw 3 . N I. on.» 18...... . 118m . llooe 118... 00.0 305 con be expected. The relationship between current and organic carbon is well expressed by the similarity in the isopleth potterns of median grain and organic content (Pls. 3 and 9). his foot still remains that whenever an analysis of bottom sediments is made there is hardly an exception to the relationship drawn between depth and organic carbon. ORGANIC CARBON AND SORTINQ -- he relationship between Organic carbon and sorting is shown in figure 36. As in acid “Olubles, an interrelationship between grain-size, sorting, ‘nd organic carbon is seen. Low organic carbon percentage is tound in sediments which are well sorted. A high amount of oll’gsnic carbon, which normally occurs in the fine-grained Infiterials, is associated with the more poorly sorted sediments. LOcal factors alter this correlation. ORGANIC CARBON AND SKEWNESS -- Figure 37 shows the I‘elationship between organic carbon and skewness. Sediments altewed far to the coarse side contain more than 2.00 per cent organic carbon. Those with near zero skewness or skewed to the fine side contain less than 2.00 per cent organic carbon. ORGANIC CARBON AND CURRENTS -- Inasmuch as Saginaw 8“? is practically void of plant life, there is some question ‘. to how much organic material is being built up in sediments by planktonic type growth. It seems probable that a great p°rtion of the organic carbon is derived from humus from the r °rt11e lowlands. Although 11. is carried into the bay through 306 oz_pmom as com. 02.. com. com. co... co». ozimom 2, 5528 c.2436 .mm .52... [00.0 DINVSHO 39V1N 338 36 lNBiNOD o 9 e- I.l 006 III 00.0 lloQN 00.0 307 mm mzzmxm no. 00m.. 000.. 000. 000. 00¢. 00m. 000. 00N.l 00¢.l ____, _ _ fi_ mmmzzuxm 2 azupzou 22436 N» 23: _ _ ..II 0nd ll.00.. Ion.— DINVDUO I 8 cl 0 ‘Q N ll. 00.m I100» 39V1N3383d lNBiNOD II. 006 ll 00.0 In 00.0 8N ..... 00.0 308 rivers in flood stage, it is agreed that very little material of any kind is contributed by the rivers under normal conditions. Bevelle and Shepard (1939), in their study on San Francisco Bay sediments, found that the organic carbon could Ire traced in part to the humus from the surrounding soils. the extent of the concentration of organic carbon depends on the supply of organic material and the rate at which it is deposited. Equally important is the rate at which the inorganic materials are being deposited at the same time n.- the organics, and the rate at which decomposition occurs. In Saginaw Bay the factors, rate of deposition of organics and inorganics and the decomposition of organics, are in some respect related to current patterns. Since few sediments are being added to the bay, the concentration of any sediment, organic or inorganic, is controlled by the movement of water. Either there is movement strong enough to keep bottom materials in constant motion, or the water is (1‘11 et and complete settling takes place. Winds and currents Control the movement of the water. SUMMARY AND CONCLUSIONS Sixty-one bottom samples from Saginaw Bay were analyzed. mechanically, statistically, and chemically. The data obtained was correlated with the physical environ- ments present in the bay at the time of sampling. A body of water into which the incoming sediment load is not too great for the transporting power of the water, and the depth does not exceed that which can be swept by normal current action, contains sediments which tend to be closely related to the prevailing current directions. If currents ‘wore the single factor regulating the deposition of a quantity of sediment, a uniform distribution would result, that is, :if the sediment were in itself also of uniform size, shape, sand density distribution. It is apparent then that maps or data of any kind ‘vtiich show sediment properties in a body of water cannot express visually the many variables which are in effect, ‘tllerefore, sediments must be interpreted in light of a number of factors on which the particular data are dependent. Fae tors which must be interpreted include those pertaining 'tOb the individual grain, such as: size, shape, and density. Under special conditions still another factor, grain orien- tll»1:i.on, is included. The physical characteristic of a grain 1' Very important in the response of that grain to a given .. ' 309 310 hydraulic situation. Factors related to the physical properties of the bay and its adjacent environment are, depth of water, current velocity, incoming streams (including size and gradients), source of sediments (including amount of sediments), shoreline features, subareal and subaqueous topography, and prevailing winds. Each factor may play an important part in the move- ment and deposition of a single grain of sand. No one physical characteristic of a sand grain may act independently of another, although the dependency is not always perceptible. -Each attribute must be considered or interpreted with regard to its relation to one or more of the many variables. Thus, it is through the study of the physical characteristics and depositional environments of recent sediments that more is learned of the environment of ancient sediments. Saginaw Bay, with the exception of its open end where the floor slopes off sharply into Lake Huron proper, is very shallow. The bottom sediments, therefore, are subject to constant turbulence caused by wave and current action. Median diameter distribution corresponds closely to the pattern of current flow outlined by Ayres, et al, (1956). It is thought that the main current enters Saginaw Bay from the north around Au Sable Point, continues to the west end of the bay where it is deflected to the south shore, then leaves the bay to the south around Point aux Barques. Minor variations are noticeable in the west half of the bay, 311 including the area of deep water which fills the old Saginaw River channel. Currents for the most part, appear to be deflected toward the center of the west half of the bay. There is evidence of minor littoral currents along the northwest shore from Point Lookout to Nayanquing Point. A belt of coarse material along the southeast shore, west of Katechay Island, suggests that the Saginaw River is deflected in a southward direction. In the vicinity of Sand Point the main path of currents is deflected further toward Charity Island. This leaves the shoreline between Sand Point and Rat Point open to sand accumulation. The currents move landward in the vicinity of Rat Point. The southward deflection of the main current at Hat Point may be a result of either prevailing winds or lesser currents which enter Saginaw Bay from Lake Huron. Johnson (1958) noted a variation in the currents as a result of wind action. Drift bottle studies did not indicate prevailing currents. Closely related to the distribution of grains ac- cording to size is the sorting of grains according to shape and density. The same factors which affected grain-size distribution play an important role in the sorting of particles. Poor sorting is more prominent in fine sediments in deep water. This poor sorting may be the result of strong currents, wave action, or ice rafting. Glacial lag concentrates may result in mixing of coarse with fine ma- terials in quiet water. 312 A zone of very poorly sorted coarse sediments is along the extreme southeast shore. Materials coming from the Saginaw River in floor stage are added constantly to this zone and the sediments never assert themselves. Sorting in Saginaw Bay in general is more of a function of currents than depth. This is true in spite of the relation between fine-grained sediments and poor sorting. The concentration of heavy minerals closely parallels the paths of stronger currents. Local deviations in currents are common. Heavy mineral percentages are generally less than five percent throughout the bay. Up to 11 per cent are present locally. Heavy minerals derived from the surrounding drift are not likely to display any sign of orderly distribution ac- cording to species. Species distribution is more obvious in areas which are hydraulically suited to a given mineral characteristic. For example, magnetite and hematite show a high degree of sphericity and roundness and, because of their high specific gravity, they probably adjust to traction transportation. These minerals concentrate where elongate, tabular, and less dense amphiboles and pyroxenes are in- frequent. The reverse relationship holds true in that where amphiboles and pyroxenes are plentiful, the metallic opaques are sparse. This seems to suggest that a mineral character- istic can be related to a given hydraulic condition. 313 Heavy mineral suites from rivers entering into the bay display the same randomness as observed in the bay sediments. Metallic opaques from the Rifle River are an exception. Roundness and sphericity factors are remotely related to the current direction. Such a relation is probably a result of selective sorting due to the ability of a grain to be moved according to its shape, either by suspension or traction, and not to the degree of abrasion as a result of strong currents. Grains, for the most part, are only moderately rounded, but they show a fairly high degree of sphericity. No obvious relation exists between the two factors. Only a small amount of material is fed into the bay by the streams, and that which is deposited is derived from glacial drift and the few outcrops near the bay shores, thus the sand represents an undeterminable number of erosional and depositional cycles. In this respect, depositional environments cannot be determined from the interpretation of roundness and sphericity data. Roundness and sphericity should instead be viewed in light of their aid in selective sorting of sand grains. Acid soluble material in the sediments is low, averaging for the most part below one per cent. In places more than three per cent was determined. Acid solubles are correlated with the fine shell fragments accumulated in fine sediments. Relatively high acid soluble content in coarse sediments 314 particularly in the southeast corner of the bay, may be accounted for by detrital limestone weathered from outcrops and boulders along the shore and from shell fragments carried in by large populations of waterfowl. Organic content in the bay sediments may amount to as much as seven per cent. Generally, however, the average is less than one per cent. Carbonaceous material is more prevalent in the fine-grained sediments. Its source is largely from planktonic material and humus of the surrounding farmland. There is very little weed plantlife in the bay. Organic carbon appears more nearly related to depth than any other factor. However, the distribution and rate of deposition of organic and inorganic sediments is largely a function of winds and currents. Krumbein (1945) noted that, "The relations between sediment patterns and energy or process 'patterns (waves, currents, winds) afford an insight to the combinations of factors which produce sediments of given characteristics." 11:: Saginaw Bay the physical properties of the sediments are illutimately controlled by wind, current, or wave action. Silepard and Moore (1955) defined a sedimentary environment ‘8 a, "...spatial unit in which external physical, chemical find biological conditions and influences affecting the d‘evelopment of a sediment are sufficiently constant to form ll characteristic deposit." 315 Thus it may be said that the sediments in Saginaw Bay, and other bodies of water of similar hydraulic charac- teristics, conform to the current patterns, with local exceptions, and produce a sedimentary deposit which may be described in light of these hydraulic conditions. This must be qualified by saying that the local variation in the sediments of Saginaw Bay is a result of depth, source and supply of sediments, and surrounding physiography. One should expect that the shallow water deposits which are controlled largely by wave and current action to vary according to these same factors. Consequently, a transition of sedimentary charac- teristics will occur which show a degree of complexity proportional to the complexity of the surrounding control- ling agents. It was found that sediments correlative of certain ¢3onditions in shallow water were more likely to be the ex- cseptdon in deep water environments. The final deposit Icy respond not only to depth of water, source and supply or material, but to the environment of the body of water into which it is being deposited. Is the body of water receiving the sediments an open bay, a protected lagoon, find is the surrounding topography gentle or rugged? An example of this association is shown by a series of b“?! along the southern California coast which are not only in. the same climatic zone but are geographically closely related and are bordered by a similar rock. A great 316 difference in topography has provided a striking difference in organic carbon, acid soluble content, and median grain size distribution of the sediments in each bay (Emery, et al, 1957). It is from the study of recent sediments that one can establish, with qualification,laws of sedimentary deposition applicable to ancient sediments. Uniform conditions which produce fine-grained deposits in deep water farthest from the shore, a transition of coarse to fine sediments according. to depth and distance from shore or source, and sorting related to distance from source of material are virtually nonexistent. Correlation on the basis of such.supposition should be restricted to small areas. However, once one hasestablished the variables to idlich sedimentary deposition conforms, and when the charac- teristic deposit that is formed according to these variables is determined, then a sedimentary environment may be con- ceived. Recent sediments should provide the key to the Belution of this problem. As a result of the analysis of the bottom sediments 'Jf Saginaw Bay the following conclusions are made with regard to shallow water deposition: 1. Median diameter may reflect prevailing currents since the distribution of a given size grain is more a function of current than depth of water. 2. Sediments respond to environments through selec- tive sorting according to shape, density and size. _ h... _ _ 317 Heavy minerals, whose source is from glacial sediments, are not distributed according to mineral suites. The concentration of heavy minerals may be a function of current velocity. Roundness and Sphericity are not a measure of abrasion by currents. Distribution of rounded and spherical grains is probably a result of selective sorting. The distribution of organic carbon in the sediment is primarily a function of currents and grain size. The amount of acid solubles in the sediment is probably related to source of material rather than current or depth. It is evident from this study that an interpretation of a depositional environment on the basis of physical or chemical analyses is uncertain in a heterogenous shallow water environment such as that of Saginaw Bay. Depositional environments comparable to Saginaw Bay are rare. BIBLIOGRAPHY Adams, M. P. Saginaw Valley Report, Michigan Stream Control Commission, 1937. Alexander, A. E. A Pgtrographic and Petrologic Study of Some Continental Shelf Sediments, Jour. Sedimentary Petrology, vol. 4, No. 1, pp. 12-22, 1934. Alexander, L. T. and Byers, H. G. A Critical Laboratory Review of Methods of Determining Organic Mgttgr and Carbonate in Soil, U. 8. Dept. of Agr. Tech. Bull. 317, pp. 1-29, 1932. Allen, P. Carrelation Between Allogenic Grade Size and All eni Fre uen , Jour. Sedimentary Petrology, vol. 17, No. 1, pp. 3-7, 1947. Antevs, E. Climggeg 21 thg Last Giggigtign in Ngrth Ameriga, Am. Jour. Sci., vol. 228, pp. 304-311, 1934. Ayers, A. 0., Anderson, D. V., Chandler, D. C. and Lauf, G. H. Currents and Water Masses of Lake Huron (1954 Syn- o tic Surve , Ontario Dept. of Lands and Forests, Div. of Res. Ontario), Res. Rept. No. 35. Univ. of Mich. Great Lakes Res. Inst. (Michigan), Tech. Paper No. l, 1956. Baker, 6. Sand Drift at Portland, Victoria, Augtralia, Proc. Royal Soc. Victoria, vol. 68, 1956. Bay, J. V. Glacial History of thg §tregm§ 9f Southeastern Mighigan, Cranbrook Inst. of Sci., Bull. 12, 1938. Baal, M. A. and Shepard, P. P. A Use of Roundness to De- termine De 0 itional Environments, Jour. Sedimentary Petrology, vol. 26, No. 1, pp. 49-60, 1956. Bretz, J. H. Caugeg 2f the Glacial Lake Stages in Saginaw Basin, Michigan, Jour. Geology, vol. 59, No. 3, pp. 244-258, 1951. . Glagia; Gyagg River, Michigag, Mich. Acad. Sci. and Letters, vol. 38, 1952. Caldwell, L. T. Areal Variations of Calcium Carbonate and Heavy Minerals in Barataria Bay Sediments, Lguisiana, Jour. Sedimentary Petrology, vol. 10, No. 2, pp. 58- 64, 1940. 318 319 Carsola, A. J. Recent Marine Sediments from Alaska and Northwest Canadian Arctic, Am. Assoc. Petroleum Geologists Bull., vol. 38, No. 7, pp. 1522-1586, 1954. Cooper, W. P. Geological Report on Bay County, Michigan, Geol. Survey, 1905. Croxton, P. E. and Crowden, D. J. Applied General Statistics. Prentice-Hall, Inc. New York, p. 314, 1947. Davis, C. A. Report of the Geology of Tuscola County, Michigan. Rept. of the State Board of Geological Survey of Michigan, 1908. Dixon, J. W. and Massey, P. J., Jr. Introduction to Statistical Analysis, McGraw-Hill Book Co., Inc., New York, pp. 79-80, 1957. Dryden, A. L., Jr. Accuragy in Percentage Representation pf Heav Mineral Pre uencies, Nat. Acad. Sci. Proc., vol. 17, No. 5, pp. 233-238, 1931. Dryden, A. L. and Dryden, C. Cpgpapptiye Rates 9; Weathering p£:Some Common Heavy Mineral , Jour.Sedimentary Petrology, vol. 16, No. 3, pp. 91-96, 1946. Emery, K. 0., Gorsline, D. 8., Uchupi, E. U., and Terry, R. D. Sediments of Three Bays of Baja Califorpig: Sebaptipn Visca'n San Crist bal and Tod s Santos, Jour. Sedi- mentary Petrology, vol. 27, No. 2, pp. 95-115, 1957. Ericson, D. B., Ewing, V. M., and Heezen, B. 0. Deep Sea Sand; and Submarine Canyons, Geol. Soc. America Bull., vol. 62, No. 8, pp. 961-965, 1951. Flint, R. P. Glacial Pleistocene Geol , John Wiley and Sons, In., New York, pp. 342-349, 1957. Greenman, N. M. Recent Marine Sedimepts and Environments of Northwest Gulf of Mexico, Am. Assoc. Petroleum Geologists Bull, vol. 40, No. 5, pp. 813-847, 1956. Griffiths, J. C. Size and Sorting in Sediments, Geol. Soc America Bull., vol. 62, No. 12, Pt. 2, P. 1551, 1951. . Size Versus Sorting in Some Caribbean Sediments, Jour. Geology, vol. 59, No. 3, pp. 211-243, 1951. Gripenberg, S. S d’ments of the Baltic Se Recent Marine Sediments, 3A Symposium), Edited by P. D. Trask, Am. Assoc. Petroleum Geologists, pp. 298-321, 1939. Hooper, P. A. Personal Communication, 1958. 320 Hough, J. Sediments of Buzzards Bayl Massachusetts, Jour. Sedimentary Petrology, vol. 10, No. 1, pp. 1932, 1940. . Sediments of Cape Cod Bay, Massachusetts, Jour. Sedimentary Petrology, vol. 12, No. 1, pp. 10-30, 1942. . The Bottom Deposits of Lake Michi an, Jour. Sedimentary Petrology, vol. 5, No. 2, pp. 57-80, 1935. Inman, D. L. Measure; fpr Depcribing the Size Distributipn of Sediments, Jour. Sedimentary Petrology, vol. 22, NOo 3’ Ppe 125-145, 1952e . and Chamberlain, T. K. Partigles Size Distri- butipn in Nearshore Sediments, "Finding Ancient . Shorelines”, Special Publ. No. 3, Sec. Econ, Paleon- tologists and Mineralogists, Tulsa, Okla., pp. 106- 127, 1955. . Sorting of Sediments in the Light of Fluid Mechanics, Jour. Sedimentary Petrology, vol. 19, No. 2, pp. 51-70, 1949. Kelley, T. L. Statistical Methods, London, p. 77, 1924. Kelley, W. A. A Review of the Stratigraphy of the Saginaw Formation, Mich. Acad. Sci, Papers, vol. 14, p. 468, 1930. Krumbein, W. C. A Time Chagt for Mechanical Analysig by the Pi ette Method, Jour. Sedimentary Petrology, vol. 5, pp. 93—95, 1935. . Gra hic Presentation and Statistical Anal si of Sedimentar Data, Recent Marine Sediments, 1A Symposium), Edited by P. D. Trask, Am. Assoc. Petroleum Geologists, pp. 558-591, 1939. . Measurement and Geological Significance of Shape and Roundness of Sedimentary Particles, Jour. Sedi- mentary Petrology, vol. 11, No. 2, pp. 64-72, 1941. . Application of Logarithmic Moments to Size Preguency Distributions of Sedimentp, Jour. Sedi- mentary Petrology, vol. 6, No. 1, pp. 35-47, 1936. . Recent Sedimentation and the Search for Petrole- . Am. Assoc. Petroleum Geologists, Bull., vol. 29, o. 9, pp. 1233-1261, 1945. 11 Z .. Sediment! apd Egponential Qurvep, Jour. Ge- ology, vol. 45, No.5, pp. 577-601, 1937. f .. 1ha_Eifaaia_nf_AhLasian_2a_ihe_§isai_§hansi R nd es f R ck Pra ments Jour. Geology, vol. 49, No. 5, 482-520, 1941. . me use pf Quartile Measures in Describg’pg apd 99mparing ediments, Am. Jour. Sci., 5th Ser., vol. 32, No. 133, pp. 99-111, 1936. . and Aberdeen, E. J. §ed1mepts of Bargtgria Bay, Louisiana, Jour. Sedimentary Petrology, vol. 7, No. 1, pp. 3-17, 1937. , and Caldwell, L. T. Area; Variation of Organic Carbon Content of Baraparia Bay Sediments, Lpuisiana, Am. Assoc. Petroleum Geologists, Bull., vol. 23, No. 4. pp. 592-594, 1939. , and Miller, R. L Design of Experiments for Statistical Analysig of Geologipal Data, Jour. Ge- ology, vol. 61, N01 6, pp. 510-532, 1953. , and Pettijohn, P. P. Manual of Sgdimgntary Pe- prology, D. Appleton-Century Co., New York, 1938. , and Rasmussen V. C. The Probable Error pf Sampling Bgaph Sand; fpr Hegvy Minpral Anglypis, Jour. Sedimentary Petrology, vol. 11, No. 1, pp. 10-20, 1941. Kuenen, Ph. N. Marine Geol , John Wiley and Sons, Inc., New York; Chapman and Hall, Lmtd, London, pp. 27- 56, 210-297, 399-403, 1950. . Lane, A. C. Coal of Michigan, Its Mode. It Occurrence. and L Quality, Mich Geol. Survey, vol. 8, Pt. 2, 1902. . Geplpgical Report on Hurpn County, Michigan, Geological Survey of Michigan Lower Peninsula, vol. 9, Pt. 2, (1900) 1393-1900. . Water Repources of Lower Peninsula of Michigpn, U. S. Geol. Survey Water-Supply Paper 30, pp. 57-91, 1899. Lauff, G. H. Some Aspects of the Physical Limnology of Grand Traverse Day, Great Lakes Res. Inst. Publ. 2, Univ. of Mich., 1937. Leverette, F. Correlation of Beaches with Moraines in Huron and Eric Basins, Am. Jour. Sci., vol. 237, pp. 456- 457, 1939. 322 , and Taylor, F. B. The Pleistocene of Indiana gpd Michigan and the History of the Great Lakes. U. S. Geol. Survey Mon. 53, pp. 55-273, 1915. McKelvey, V. E. Thg Flpigtion pf Sgnd in Nature, Am. Jour. Sci., vol. 239, No. 8, pp. 594-607, 1941. Mann, J. F. The Sediment! of Lake Elsinore, Riverside County, California, Jour. Sedimentary Petrology, vol. 21, No. 3, pp. 151-161, 1951. Martin, H. M. Geological Map of the Southern Peninsula of Michi an, Mich. Geol. Survey Publ. 39, Geol. Ser. 33, Ann. Rept., 1936. Menard, H. H. Sediment Movement in Relation to Current Velocit , Jour. Sedimentary Petrology, vol. 20, No. 3’ ppe 148-160’ 19500 . Transportation of Sediment bygBubbles, Jour. Sedimentary Petrology, vol. 20, No. 2, pp. 98-106, 1950. Morris, W. J. Effects of Sphericity, Rpundness and Velocity of Traction Transportation oi Sand Grains. Jour. Sedimentary Petrology, vol. 27, No. 1, pp. 27-31, 1957. Mudge, E. H. Some Features of Pre-Glapial Drainage in Migh- i an, Am. Jour. Sci., vol. 4, pp. 383-386, 1897. . Further note; on Pro-Glacial Drainage in Mich- i an, Am. Jour. Sci., vol. 10, pp. 158-160, 1900. Newcombe, R. B. Oil and Gas Fields of Michi an, Michigan Geol. Survey Publ. 38, Geol. Ser. 32, pp. 8-102, 1932. Otto, G. H. Comparative Tests of Several Methods of Sampling Heav Mineral Concentrates, Jour. Sedimentary Petrology, vol. 3, No. 1, pp. 30-39, 1933. Pettijohn, F. J. and Lundahl, A. C. Spape gnd Roundness of Lake Erie Beach Sands, Jour. Sedimentary Petrology, vol. 13, No. 2, pp. 69-78, 1943. , and Ridge, J. D. A Mineral Variation Series of Beach Sands from Cedar Point, Ohio, Jour. Sedimentary Petrology, vol. 3, No. 2, pp. 92-94, 1933. 323 Revelle, R and Shepard, F. P. Sediments off the California Coast, Recent Marine Sediments (A Symposium), Edited by P. D. Trask, Am. Assoc. Petroleum Geologists, pp. 246-281, 1939. Rhodehammel, E. C. An Interpretation of the Pre-Pleistocene Geomorphology of a Portion of the Saginaw Lowland, unpublished thesis, Mich. St. Univ., 1951. Riley, N. A. Pro'ection S hericit , Jour. Sedimentary Pe- trology, vol. 11, No. 2, pp. 94-97, 1941. Rittenhouse, G. Analytical Methods as Applied in Petrographip Investigations of Appalachian Basin, U. S. Geol Survey Circular 22, pp. 1-20, 1948. . Transportation and Deposition of Heavy Minerals, Am. Assoc. Petroleum Geologists, Bull., vol. 54, Pt. 2, No. 12, pp. 1723—1730, 1943. Robinson, W. O. The Determination of Organic Matter in Soil; by the Hydrogen Peppgide Methpd, Jour. Agr. Research, vol. 34, pp. 339-356, 1927. Rubey, W. W. The Size Distribution of Heavy Minerals Within a Mater-Laid Sandstone, Jour. Sedimentary Petrology, 701. 3, N0. 1, ppe 3-29, 1933s Russell, R. D. The Size Distribution of Minerals in Miss- issi i Sands, Jour. Sedimentary Petrology, vol. 6, No. 3, pp. 125-142, 1936. __ . Effect of Transportati n on Sedimentar Parti- clep, Recent Marine Sediments, (A Symposium) Edited by P. D. Trask, Am. Assoc. Petroleum Geologists, pp. 32-47, 1939. , and Taylor, R. E. Roundness and Spape of Mississippi River Sands, Jour. Geology, vol. 45, No. 3, pp. 225-267, 1937. Schollenberger, C. J. Determination pf Soil Organic Matter and Carbonates. Soil Science, vol. 59, pp. 53-63, 1945.' Shepard, F. P. and Moore, D. G. Central Texas Coast Sedi: ggptation: Characteristics of Sedimenpggy Environ- ment. Recent History and Diagenesis, Am. Assoc. Petroleum Geologists, Bull., vol. 39, No. 8, pp. 1463- 1593, 1955. ’ 324 , and Moody, C. L. Study of Near-Shape Recent Sediments and Their Envigonment ip the Northern Gulf of Mexico, Am. Petroleum Inst., Res. Project 51, 1953. Sherzer, W. H. U. S. Geol. Survey Geol. Atlas. Detroit folio, No. 205, pp. 1-14, 1917. Shukri, N. M. and Higazy, R. A. Mechanical Analysip of Bottom De osits of the Red Sea, Jour. Sedimentary Petrology vol. 14, No. 2, pp. 43-69, 1944. Sindowski, H. F. K. R t and Prob ems of Heav Mineral Analysig in Germany: A Review of Sedimentary Peta; ological papers, 1936-1948, Jour. Sedimentary Petr- ology, vol. 19, No. 1, pp. 3-25, 1949. Spencer, J. W. A vaiew of the History of the Great Lakes, American Geologist, vol. 14, No. 5, pp. 286-310, 1894. Stetson, H. C. and Schalk, M. Marine Erosion of Glacial Depopits in Masgachusetts Bay, Jour. Sedimentary Petrology, vol. 5, No. 1, pp. 40-51, 1935. Strahler, A. N. Statistical Anal sis in Geomor hic Research, Jour. Geology, vol. 62, No. 1, pp. 1-25, 1954. Taylor, F. B. The Glacial and Post Glacial Lake; of the Great Lakes Region, The Smithsonian Inst. Ann. Rept., pp. 291-327, 1912. . Correlation of Erie-Huron Beaches with Outlets and Moraines in Southeastern Michigan, Geol. Soc. America Bull., vol. 8, No. 1, pp. 31-58, 1897. Trask, P. D., Patnode, H. M., Stimson, J. L. and Gray, J. R. Geology and Biology of North Atlantic Deep-Sea Cores Between Newfoundland and Ireland, U. S. Geol. Survey Prof. Paper 196-E, Pt. 8, Organic Content, pp. 142-147, 1942. . 0 ni Content of Recent Mar'ne Sediments, Recent Marine Sediments, (A Symposium), Edited by P. D. Trask, Am. Assoc. Petroleum Geologists, pp. 428-453, 1939. . Mechanical Analysis of Sediments by Centrifuge, Econ. Geology, vol. 25, pp. 581-599, 1930. 325 Trowbridge, A. C. and Shepard, F. P. Sedimentation in Massachusetts B , Jour. Sedimentary Petrology, vol. 2, No. 1, pp. 3-37, 1932. Twenhofel, W. H. The R din of Sand Grains, Jour. Sedi- mentary Petrology, vol. 15, No. 2, pp. 59-71, 1945. . The Spdiments of Lake Florence and Lake Lucy, Central Florida, Jour. Sedimentary Petrology, vol. 23, N0. 4, pp. 272-279’ 1953. , Treatise on Sedimentation, Williams and Wilkins, Baltimore, Md., p. 645, 1932. ‘_, and Tyler S. A. Methods of Stud of Sediments, McGraw-Hill Book Co., Inc., New York, pp. 105—116, 1941. U. S. Lake Survey Chart No. 52, Lake Huron (Point aux Barques to Oscoda including Saginaw Bay), U. S. Corps of Engineers, Detroit, Michigan, 1955. von Engeln, 0. D. Geomor holn , McMillan Co., pp. 49-55, 477-479, 1942. Wadell, H. Volume, Shape, and Roundneps of Rock Particles, Jour.Geology, vol. 40, No. 5, pp. 443-451, 1932. Walkley, A. Determinin Or anic Carbon in Soils, Soil Science, vol. 63, pp. 251-264, 1947. "fig”; er F13! “U ’1'” '13": LEW-L MICHIGAN STRTE UNIV. LIBRnRIEs 1111111111111111111111111111111111 31293011027624 A A —¥4 1:1." 0.31.1217!!!