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Xerox University Microfilms 300 North Zoob Rood Ann Arbor, Michigan 43106 73-20,3211 CHUNG, Pham Kim, 19tf3MISSISSIPPIAN COLDWATER FORMATION OF THE MICHIGAN BASIN. Michigan State University, Ph.D., 1973 Geology University Microfilm s, A XEROX Com pany, Ann Arbor, M ichigan MISSISSIPPIAN COLDWATER FORMATION OF THE MICHIGAN BASIN By Pham Kim Chung A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Geology 1973 ABSTRACT MISSISSIPPIAN COLDWATER FORMATION OF THE MICHIGAN BASIN By Pham Kim Chung The stratigraphic study of the Coldwater Formation (Early Mississippian) of Michigan has been undertaken with the objective to interpret the nature of lateral changes in lithology; to gather information adding to a better under­ standing of the direction, as well as the nature, of the source; to present a better picture of Early Mississippian paleogeography; and to relate facies to the implied sedi­ mentary environments and to Early Mississippian paleostructural development. Detailed structure contour and isopach maps were constructed employing about 775 control wells. The con­ struction of cross-sections and lithofacies maps resulted from a microscopic observation of about 180 well cutting sets. The results show that the eastward thickening of the formation relates to the proximity of an eastern source and the subsidence of the major depositional center Pham Kim Chung in eastern Michigan. A secondary basin near the present center in central Southern Michigan is inferred to have effected the sedimentary conditions at time of the deposi­ tion. The Coldwater sediments are mostly marine. The eastern facies is sandy consisting of up to a maximum of 40 percent sandstone; the western facies consists of mostly shale and some impure carbonates. The X-ray dif­ fraction method was used to determine the clay mineral composition of the Coldwater sediments. Kaolinite, illite and chlorite mainly form the clay mineral suite, with a markedly higher proportion of kaolinite in the coarser elastics. The sediments were derived largely from the Laurentian Highlands. They were formed by a delta in the area of the Findlay Arch, and the Coldwater shale in Michigan is considered a pro-delta. eastern Michigan wan shallower ami the offshore area in the west. The nearshore sea in Leas saline than in The sourco area is believed to have consisted of granitic and/or gneissic rocks weathering under a warm climate and high rainfall. The Upper Devonian-Lower Mississippian sediments in Michigan represent a succession of two transgressiveregressive "cycles"— the Antrim-Bedford-Berea cycle and the Sunbury-Coldwater-Marshall cycle— each characterized by a lower black shale unit followed by a gray shale and a sandstone. Coldwater deposition starts the regressive Pham Kim Chung phase in Michigan and is a prelude to active evolutionary changes in the Michigan Basin during the Marshall and up to at least Middle Mississippian (Meramecan) time. ACKNOWLEDGMENTS The author wishes to express his sincere gratitude to Dr, Chilton E. Prouty, who suggested the problem# gave invaluable advice and gave freely of his time for con­ sultation. M a n y thanks are extended to Professors A. T. Cross# M. M. Mortland and R. L. Anstey# other members of the guidance committee# for their suggestions and con­ structive criticism of the manuscript. Thanks are also offered to Mr. David Lietzke, Department of Soil Science# Michigan State University# who provided assistance in use of the X-ray diffractometer. The generous permission to use the X-ray equipment and laboratory facilities of the Department of Soil Science# Michigan State University, as granted by Dr. Mortland is sincerely appreciated. The writer is indebted to the Agency for Inter­ national Development# Washington# D.C., for scholarship support. ii TABLE OF CONTENTS Page A C K N O W L E D G M E N T S ....................... ii LIST OF TABLES........................................... V LIST OF F I G U R E S ........................................ vi I N T R O D U C T I O N .................. ....................... 1 Scope and P u r p o s e .............................. Previous W o r k ................................. Methods of Investigation....................... 1 1 4 TECTONIC FRAMEWORK OF THE MICHIGAN BASIN . . . . . Regional Setting of the Michigan Basin . . . Intrabasinal Structures ........................ Structure of the Michigan Basin During Coldwater Deposition.............................. S T R A T I G R A P H Y ....................... Introduction..................................... Vertical Relationship of the Coldwater F o r m a t i o n ..................................... Problems of Nomenclature and Correlation . . Description of the Coldwater Formation . . . 6 6 10 12 17 17 24 26 36 ENVIRONMENTAL INTERPRETATION ........................... 91 PALEOGEOGRAPHY............................................ 99 General Setting. ........................... 99 Paleogeography During Deposition of the Antrim, Bedford and Berea Formations . . . 100 Paleogeography During Deposition of the Coldwater F o r m a t i o n .................................. 103 CYCLIC SEDIMENTATION OF UPPER DEVONIAN AND LOWER MISSISSIPPIAN ROCKS IN MICHIGNA .................... 109 Antrim-Bedford-Berea Sequence ................. Sunbury-Coldwater-Marshall Sequence . . . . 109 Ill Page Time-Stratigraphic Correlations.... ............ CONCLUSIONS.......................................... BIBLIOGRAPHY ................................. APPENDICIES................... 117 118 122 130 Appendix I— Statistical Analysis . . . . . Appendix II— List of Well Samples Used for Lithofacies M a p s ............. ... Appendix III— List of Wells Used for Isopach and Structure Contour Maps . . iv 131 134 140 LIST OP TABLES Table 1. Page Chart Showing Stratigraphic Names Applied to the Post-Berea Lower Mississippian Rocks . 2. Regional Correlation C h a r t ................... 34 3. List of Well Samples Used for X-ray Experiments. 4. Flow-sheet of X-ray P r o c e d u r e ................ 76 5. X-ray Diffraction Data for Clay Minerals (Different T r e a t m e n t s ) ...................... 78 6. X-ray Diffraction for Clay Minerals and Quartz 7. Illite/Kaolinite + Chlorite and Chlorite/ Kaolinite + chlorite Ratios ................. V . 30 74 78 85 LIST OF FIGURES Figure 1. Page Major Structural Trends— Michigan Basin and ..................................... Environs 7 2. Major Fold Axes— Southern Michigan 9 3. Structure Contour Map at Base of Coldwater F o r m a t i o n ................ 13 4. Isopach Map of the Coldwater Formation . . . 15 5. Bedrocks of Southern Michigan .................. 18 6. Stratigraphic Succession in Michigan. 20 7. Stratigraphic Cross-section AA* .............. 41 8. Stratigraphic Cross-section BB* .............. 42 9. Stratigraphic Cross-section CC' .............. 43 10. Cross-section D D * ............................... 44 11. Michigan Coldwater Formation: Sand Percentage..................................... 46 Michigan Coldwater Formation: Clastic Percentage..................................... 48 13. Michigan Coldwater Formation: Shale Color. . 50 14. Michigan Coldwater Formation: Red Rock Facies 51 15. "Standard Section" of Eastern Coldwater. 16. Aeral Distribution of the "Richmondville" S a n d ........................................... 70 17. X-ray Diffractogram— Sample 8A ................. 80 18. X-ray Diffractogram— Sample 4 B ................. 81 19. X-ray Dif fractogram— Sample 1 0 C .............. 82 20. Illite / Kaolinite + Chlorite Ratio (Lower T h i r d ) ........................................ 86 Illite / Kaolinite + Chlorite Ratio (Middle T h i r d ) ........................................ 87 12. 21. vi . . . . . . . . -. 67 Figure 22. 23. Page Illite / Kaolinite + Chlorite Ratio (Upper T h i r d ) ........................................ pr Depositional Environment of the Coldwater F o r m a t i o n ..................................... 97 24. Paleogeography during Bedford-Berea Delta Deposition......................................... 102 25. Paleogeography during the Early Stages of the Coldwater D e l t a ........................... ■ . 104 26. Paleogeography during the Late Stages of the Coldwater Delta and Earliest Stage of the Marshall U n i t ..................................... 108 27. Trangressive-Regressive "Cycles?'of the Late Devonian and Early Mississippian in Michigan no 28. Antrim-Bedford-Berea-Cycle 1 112 29. Sunbury-Coldwater-Marshall-Cycle 2 113 vii • INTRODUCTION Scope and Purpose The Coldwater formation (Early Mississippian) thick sequence of shale in the Michigan Basin. is a Because of a lack of economic interest, this formation has not received much attention from investigators. Most studies of the Coldwater shale to date have been either general or based on fewer well samples than available today; or have been of restricted geographic scale. This report presents the results of a stratigraphic study of this formation. The primary purposes for this study are to interpret more precisely the nature of lateral gradation within the Basin; to gather information adding to a better understanding of the likely nature and direction of the source; to contribute to the understanding of Early Mississippian paleogeography, and to relate facies to the implied sedimentary environments and to Early Mississippian paleostructural development. Previous Work Prior to the naming of the Coldwater Formation by Lane in 1893, rocks younger than Traverse and older than Marshall had been described and considered rock equivalents to at least the present formation designated Coldwater. 1 2 During the early times, geologists generally mentioned a somewhat argillaceous strata lying between coarse clastic rocks above and black shales below. Winchell (1861) assigned these argillaceous strata to the Huron group with a total thickness of 2 1 0 feet based on outcrop measurings* Four years later, Winchell reviewed the boring data and gave thickness of this group as 500-600 feet. The Huron group was believed by Winchell (1869) to correlate with the Portage group of New York and to consist of three lithologic types, shown in descending order: Huron Group Feet - Argillaceous shales and flagstones . . . 500 - Green arenaceous shale .................... 25 - Black bituminous shales (Genesee shale) . 25 The bluish shale containing of "kidney iron ore" in Branch County was considered the upper part of that Huron Group. Formation. Lane (1893) named this shale the Coldwater He stated: This formation, which has numerous outcrops in Branch and Hillsdale Counties, and is well exposed by the Coldwater River, from which I have named it, . . . I t consists of light colored greenish, or bluish, sometimes darker, shales, growing dandier toward the top and gradually passing into the Marshall. In following years, most of the literature dealing with the Coldwater Shale were very brief and cursory. 3 In 1900, in a report on Huron County, Lane dis­ cussed the geology of the Huron Group based on exposures and well data and also compiled valuable information on paleontology. Cooper (1900) in the same report correlated the Coldwater to the Cuyahoga and the lower part of Logan Formation in Ohio. Newcombe (1933) described the general lithology and historical and economic geology of the Michigan Basin. This report included a thickness contour map of the Coldwater Shale showing the outline of the depositional basin with two separate troughs trending northeast (major) and northwest (minor). Hale (1941) studied the lower Mississippian of western Michigan making special reference to the carbonate facies of that area. Monnett (1948), in a study principally on the Marshall sandstone, recognized the Coldwater as occurring in an eastern and western facies based largely on the quartz content. Cohee (1951) described the general geology of the upper Devonian and Carboniferous including the Coldwater and recognized the problem of the Coldwater-Marshall contact in eastern Michigan. Wooten (1951) studied the Coldwater in the area of the type locality, and recognized the difficulty of the 4 correlation of the surface exposures and the subsurface sections in Branch County. McGregor (1954) made a Michigan regional study of the Upper Devonian and Lower Mississippian rocks which he divided into lithologic groups, the Coldwater Shale and Marshall Sandstone forming one group. Lithofacies and isopach maps were constructed for the combined units. Though a helpful background reference, the stratigraphy of the Coldwater is not singled out and is somewhat lost in his interpretation of the combined formations handled as a unit. LeMone (1964) touched on the Coldwater shale in a study directed mostly at the Antrim and Ellsworth Forma­ tions but did show the Coldwater in a regional isopach map for Michigan, and structure and isopach maps for Bay County, Michigan. Methods of Investigation Except for a few outcrops found in Branch, Hills­ dale, Calhoun, Huron and Sanilac Counties, the formation is unexposed within the Basin. Most of the information obtained in this study is from subsurface data. Examina­ tion of samples were made by binocular microscope from well cuttings of the Michigan State University Department of Geology, no well cores being available. This technique was considered appropriate for the semi-quantitative 5 results sought regarding sand percentages and clastic ratios. Sand sizes w e r e measured b y a micrometer occular and grains above 1/16 mm. were placed in the sand grade size with silt placed with the clay-sized fraction. Where a mixed lithology, as sandy shale, was encountered, the percentages of sand and clay for the sample interval were estimated and placed w i t h their respective grade size categories. A few cross-sections were constructed for correla­ tion purposes as well as to demonstrate the facies changes. Regional isopach and structure contour maps were* constructed employing about 750 control wells. Several composite samples chosen from several wells representing basinal spacing were X-rayed to determine the clay mineral suites as well as to check any significant vertical and lateral changes in clay minerals. Finally, depositional environments of the Coldwater Shale were suggested b y lithologic and paleontologic data. Fossils in well cuttings are of course largely fragmented. Pieces of brachiopods, bryozoans, crinoid stems and some well preserved ostracods were observed. Paleontologic data compiled in the literature also added information to the understanding of environment of the Coldwater formation. TECTONIC FRAMEWORK OF THE MICHIGAN BASIN Regional Setting of the Michigan Basin The Michigan Basin, a roughly Lircular structural depression, has been long referred to as the type example of an autogeosyncline basin. (Kay, 1951) or as an intracratonic Its center is located near the center of Southern Michigan and its flanks are outlined essentially by Lake Michigan, Lake Huron and Lake Superior. The Canadian Shield which occupies almost the m entire Lake Superior area and extends through northern Ontario, forms the northern boundary of the basin. The Basin is surrounded b y several arches; the Algonquin Arch to the east; the Findlay Arch to the east and southeast; the* Wisconsin Arch to the west; and the Kankakee Arch to the southwest (Figure 1). To the south of Michigan the north-south trending Cincinnati Arch is another structural feature. The Kankakee Arch and Findlay Arch generally are considered the western and eastern bifurcations, respectively, of the Cincinnati Arch. The Canadian Shield and the Wisconsin Highlands are Precambrian in age. The Kankakee, Findlay and Wisconsin Arches have been referred to as possible upper Cambrian age by various investigators 6 (Cohee, 1945; 7 **•*»» 'TOMj !,v' / ' (Mlkll I M CkPtAKJirjoNa jwri ^ jmim mkiimi *r«<« * J « l H N r H r M l I M il Wi PTTTTT t r a il ^ Mill 11)1 I I t tlflU lM h Ik hHMMri IHit t«»i» |tn*it«r«t «P*«r F r * v * y M AJO R S T R U C T U R A L T R C N O I-M IC H J R A N S A S IN A M D E M /lftO H S Fl«ur« I 8 Cline, et a l ., 1959). These structural features have been considered to be key factors in the formation of the Basin. The northwest elongation of the Basin and the dominant northwest and northeast directions of folds and faults (Figure 2 ) appear to be closely associated to these positive structures in one way or the other. The origin of the Basin has been a subject of dis­ cussion for many years. Newcombe (1933) related the north­ west elongation of the Basin, the northwest direction of the anticlinal trends and the downward sinking of the Basin to the compression from northeast along the Keweenaw fault. Pirtle (1932) is of the opinion that the Basin originated from simple sinking with the sediment load, and the fold trends in the Basin are related to the lines of weakness in the basement rocks. hand, Locket On the other (194 7) believed that the dominant positive features were reactivated while the negative areas were being subsided with load of sediments during the Paleozoic Era. Recently, Hinze (1963) basing his studies on gravimetric and magnetic surveys in the Southern Peninsula of Michigan suggested that the Michigan Basin had its origin in the isostatic downward yielding to the added mass of the Keweenawan basic rocks in the basement complex. But there is little doubt that since the Basin was formed, it has undergone many changes from time to time, and based Wij R ro u tiji W ll Figure 2,— Major Fold Axes— Southern Michigan. 10 on various studies of isopach and structure maps its depocenters have shifted position slightly from time to time. Intrabasinal Structures Structure contour maps based on different horizons illustrate that the Basin has an oval shape w i t h a slight northwest elongation and many structural features within the basin have two recognized major trends— northwest (dominant) and northeast. Most of the northwest folds are confined to eastern, southeastern and central Michigan; while the northeast folds occur mostly in the western and southwestern portion. Few minor east-west and north- south folds are also recognized within the Basin. Other "radial-like" structures were observed by Asseez (1967, 1969) on the Antrim shale structure contour map. In a discussion of the development of the Michigan Basin, Prouty (1971) has compiled the important anticlinal axes from the Silurian Niagarian Formation up through the Mississippian Coldwater Formation (Figure 2); some of these were considered as radial folds which are most prominent in the Salina rocks. Prouty (1971) relates these folds to the rapid basinal settling in Salina and the more sensitive response of the evaporites to deforma­ tion than other, more competent, rocks. and joints Faults (Figure 2) (Figure 1) are also recognized within the 11 Basin (Prouty, 19 71), showing primary and secondary northwest and northeast trends. Structure maps show the Michigan Basin to be a fairly symmetrical basin. Its present center, located in central Southern Michigan, is elongate somewhat northnorthwest in the deepest part. The basin centers in pre- Mississippian Paleozoic systems are believed (Prouty, 19 71) centered in eastern Michigan near Saginaw Bay, but shifted west to the present position because of stresses from the southeast, probably the Appalachians, during early phases of the Appalachian orogeny. Some studies indicate north-south barriers in south-central and west-central Michigan at various times. Hale (1941) in a study of the Lower Mississippian in western Michigan found a marked difference in sedimenta­ tion from western to eastern Michigan. This study allowed her to postulate the existence of a north-south axis extending from Calhoun County north through Eaton, Clinton, Gratiot, Isabella and Clare Counties. Later, Jodry (1951) in a study of the Traverse Group farther west recognized a western (lagoonal) (open environment) Barrier. facies and eastern facies separated by his West Michigan LeMone (1964) recognized an axis ("B" axis) farther east and indicated that it influenced sedimenta­ tion of the Antrim black shale. Asseez (1967) preferred 12 to consider the north-south axis close to LeMone's "B" axis as rather a facies barrier than a structural barrier (Figure 2) . Structure of the Michigan Basin During Coldwater Deposition It has been demonstrated difficult, and sometimes impossible, to find criteria suitable to determine the contact of the Marshall Sandstone and the subjacent Coldwater Shale in eastern Michigan. The top of the latter, therefore, cannot b e used to construct a contour map. The base of Coldwater, however, is considered a very good horizon for determining the structure of the Basin. The contact of the Coldwater and subjacent Sunbury formation is easy to determine on the basis of the black­ ness of the Sunbury shale; also the gamma-ray neutron logs show high deflections within the Sunbury shale. In the southwest part of the Basin, especially in Allegan, Barry, Van Buren and Kalamazoo Counties, the Sunbury is not recognized as a formational entity. However, another good marker bed, the lowest "red rock" in the Coldwater, serves as an adequate contact indicator with the Ellsworth shale below. As shown in Figure 3, the regional structure contour map based on about 775 wells, is constructed on the base of the Coldwater formation. recognized: i Two basin centers were one primary center located in the region of 13 M ICHIGAN COLDWATER FORMATION Structure Cl-100‘ m m m a m Figure 3.— Structure Contour Map at Base of Coldwater Formation. 14 C l a r e, Gladwin, Isabella and Midland Counties; and a smaller secondary center occurring in Iosco and Arenac Counties. This double-centered basinal feature was first noticed in the Traverse group structure contour map drawn by Cohee (1947) and later in the Dundee limestone (Bloomer, 1969). The secondary center is the area which accumulated the thickest Coldwater sediments and is con­ sidered as the principle depocenter of this time. The Howell Anticline (Figure 1) is the predominant structure in the Basin, trending in a northwest direction through Monroe, Livingston and Clinton Counties in the southeastern part of the Basin. Structural displays suggest an asymmetrical anticline with faulting occurring along the western flank of the structure (Newcombe, 1933). Kilbourn (1947) in his study of the Howell Anticline, suggested that it formed at the beginning of Coldwater time because of faulting in the basement rocks, and demon­ strated by thinning of the Coldwater formation towards the anticline. However, by means of geologic cross-section of the Howell anticline. Ells (1969) indicated that the Coldwater and Marshall thin and offlap the Howell structure, possibly because of erosion, suggesting that the folding could have occurred at least by Meramecian Mississippian) (Late time, or even possibly as late as Cretaceous time. It appears that moBt anticlinal axes manifest in the Coldwater occur in the east and northeast 15 MICHIGAN c o to * W B i formation TWckfww O r SOft f 1 Figure 4 .' •Isopach Map i r of tfte Coldwater Formation. 16 parts of the Basin. occur in Ogemaw, -Few somewhat northwest trending folds Iosco, Arenac and Bay Counties, also the region of the Coldwater depocenter. Two other struc­ turally high areas trending northwest are found in the northwestern part of the Basin: one from Wexford to Clare; and another from Lake to Mecosta Counties. These folds are also observed by the closure in the isopach map (Figure 4). Some structures without clear trends are distri­ buted throughout the western and southwestern parts of the Basin. They probably occurred on top of older eroded axes developed in the Antrim and older formations. Thus it is inferred that folding occurred at different times within the Basin. Some folds recognized within a given formation may not be developed in overlying formations. Anticlinal axes clearly observed in the Antrim shale (Asseez, 1967) may be represented by some isolated "highs" in the Coldwater. STRATIGRAPHY Introduction In the Southern Peninsula of Michigan a thick sequence of as much as 15,000 feet of sediments overlie Precambrian rocks. With the exception of the Pleistocene glacial drift and the late Jurassic "Red Beds," all the rocks lying above Precambrian belong to the Paleozoic. The rock layers occur as subcrops drift) in concentric bands (beneath the glacial (Figure 5) and dip towards central Michigan in true basinal form. All the Paleozoic systems are exposed at least locally in small exposures within the confines of the basin structure. The Cambrian is characterized by an abundance of quartz sand and carbonates. The Ordovician, Silurian, and Devonian rocks in the Michigan Basin consist mostly of carbonates and evaporites and some clastic rocks. The Mississippian time marked the return of clastic sediments in the Basin. The Devonian-Mississippian 'boundary has been a controversial problem. In Ohio, the Berea sandstone channels cut into the Bedford shale, and even the Ohio black shale. Pepper, et a l . (1954) have placed the Bedford shale, if present, or the Berea in the absence of the Bedford in basal Mississippian. 17 From 13 L^.rsVonuvl fepwwM ^Sf M i M Jurassic sfiaSI Psnnsylvanlsn \C?.^l Mississippian Mississippian. Devonian h-, -*3 Devonian M i l l Silurian (Generalized after Michigan Geological Survey, 1968) Figure 5.— Bedrocks of Southern Michigan. 19 eastern Michigan the Bedford-Berea sequence grades laterally . toward the south, southwest and west into the black shale body. Based on the stratigraphic chart published by the Michigan Geological Survey in 1964 (Figure 6), the rocks occupying the stratigraphic interval from the upper part of the Antrim shale to the base of the Coldwater was assigned to the undifferentiated Mississippian-Devonian. This sequence includes the Ellsworth and Sunbury shales in western Michigan, and the Bedford shale, Berea sandstone and the Sunbury shale in eastern Michigan. In general, the Mississippian-Devonian boundary probably occurs within the lower part of the Bedford shale and the upper part of the Ellsworth shale in the Michigan Basin. The Antrim Shale was renamed by Lane (1901) for the St. Clair shale and its type locality is in Norwood in Antrim County, Michigan. The Antrim shale which is characterized by a dominately black carbonaceous shale and an abundance of Tasmanites spores is observed through­ out the Michigan Basin. LeMone (1964), basing his study on gamma-ray neutron logs, subdivided this formation into an upper and a lower unit. The lower unit can be traced throughout the Basin and consists of three "subunits," the lowest and the highest sub-units being highly radioactive, while the middle is less radioactive than the other two. The upper Antrim unit according to LeMone is replaced by 20 STRATIGRAPHIC SUCCESSION IN MICHIGAN f A U O Z O C 1M 0 U G H O C M ImA] ITS TIM STA d H R ftS m a rt £ j I QUATERNARY momm W n M ♦ d t irfiTOi mk MBTOCM ot tommknem b fM 1 .— — QUICK* NOMtNCUTUM s^annxs 1 SUKU»*g NOWNOATUtt rOMMTIOM IM IM AM I — — CHOU* MKMtMAL TOMS ft-TVTB MWHb 33Tf*MM CHART 1 IM 4 sVvOAr.vlvJ rvpjo/rrvJ I -J'^2 Figure 6 21 . and intertongues with the Ellsworth shale west of "B" axis (Figure 2), whereas on the east side of this axis, the upper unit tends to decrease in thickness away from the axis at the same time the Bedford-Berea sequence increases in thickness. Asseez (1967, 1969) did not observe this particular subdivision but did construct a lithofacies map based on the percentage of "grayness." The darker the gray, the higher is the organic content and consequently the more reducing and "sterile" is the environment, with less decay and greater preservation of organic matter. Asseez further correlated the darker color with deeper, more poorly circulated, stagnant areas of the sea floor with the converse relationship indicating shallower areas of better aerated waters and more complete decay of organic matter. By this relationship, Asseez's lithofacies map based on "grayness" could outline areas of contrasting sea-bottom relief including structural axeB. The Ellsworth shale entered the Basin from the west at about the same time the Bedford-Berea sequence w a s being deposited on the east side of the Basin, probably along a delta front which extended to about central. Michigan. It was named (Newcombe, 1933) for exposures near the town of Ellsworth in Antrim County, Michigan. The Ellsworth is characterized by the presence of greenishgray shale which becomes darker eastward and probably interfingers with the upper part of the Antrim shale in 22 the central part of the basin. tion, Hale Near the top of this forma­ (1941) described a dolomitic zone— the "Berea horizon"— which is composed of limestone, dolomite, some oolites and rounded quartz sane grains. The north-south line which is either a structural barrier or facies barrier formed the western limit of the Bedford-Berea sequence and the.eastern limit of the Ellsworth shale. The Bedford shale and Berea snadstone form a clastic wedge lying between two black shale sequences, the Sunbury shale above and the Antrim shale below. Bedford Shale was named by Newberry The (1870) for exposures of soft blue shales at the town of Bedford, Cuyahoga County Ohio. The Bedford is typically bluish gray shale and is restricted to the eastern half of the Basin. into the overlying Berea sandstone. named by Newberry It grades The latter was also (1870) for exposures in the town of Berea, also in Cuyahoga County, Ohio. The Bedford-Berea sediments are believed to have been derived from sources in the cratonic interior, chiefly the Canadian Highlands, and form a bird-foot delta in eastern Michigan. Pepper and Dewitt (19 54) recognized a stream system subparallel to the Cincinnati Arch region leading into Ohio with dis­ tributaries into eastern Michigan. Asseez (1967) displayed the Bedford-Berea as mostly a prodelta in Michigan extending westward to about central Southern Michigan. 23 -The Sunbury Shale marked the return to a reducing marine environment yielding black muds much like the Antrim shale, lithologically. It was named by Hicks (1878) for exposures of black shale on Rattlesnake Creek, near the town of Sunbury, Delaware County, Ohio. The formation was described as a black pyritiferous, carbonaceous shale and characterized by the presence of Lingula melia and Orbiculoidea newberryi. The Sunbury, widespread throughout the entire Basin, is generally 20 to 50 feet thick; but its extreme range is from a few feet in the southwest to more than 140 feet in the "thumb" area of eastern Michigan. The Ellsworth Shale was believed (LeMone, 1964) to b e the facies equivalent of the Upper Antrim-Bedford in the Michigan Basin; the "Berea Horizon" in the upper part of the Ellsworth was considered a probable correlative of the Berea sandstone. The Sunbury black shale is followed by the Coldwater shale which is comprised of mostly clastic sediments derived from a northeastern source. It apparently marked the end of the Devonian-Mississippian black shale environ­ ment in the Michigan Basin. The objective of the present study is concentrated on the Coldwater formation. 24 Vertical .Relationship of the Coldwater Formation The Coldwater rests everywhere on the Sunbury Shale, the contact being recognizable in most places, expecially the western half of Michigan, by a red bed near the base of the Coldwater. In the few counties where this key red bed is locally absent or located stratigraphically higher than the Coldwater base, the top of the Sunbury shale, recognized by its blackness, can be UBed to mark the contact without significant error. In central part of the Basin where the Bedford-Berea sequence and the Ellsworth wedge out, it is difficult to distinguish the Sunbury from the Antrim shale. Most investigators prefer to consider the Coldwater in contact with the Sunbury in this region instead of with the Antrim black shale. In southwest Michigan, where there exists little or no typical Sunbury the red bed at base of the Coldwater ' shale can be used to define the Ellsworth-Coldwater contact. The Coldwater-Marshall contact, especially in eastern Michigan, is still an unresolved problem today. The Coldwater shale grades upward into the Marshall .sand­ stone. Lane (1900) compiled data on all the outcrops along the Lake Huron shore in Huron County and well data available at that time placing the Coldwater-Marshall contact at the base of the "Grindstone" beds in section 30, T. 19N., R. 14E. Based on this, the Coldwater shale appears to be less than 1000 feet and the Marshall 25 sandstone is measured up to '560 feet in northern Huron County. Monnett (1948), questioning these thicknesses as recorded by Lane, believed that the Coldwater should be thicker because of the eastward thickening of that, unit towards the source area. He preferred considering the rocks cropping out along the lake shore in northern Huron County as a transition zone called the Coldwater-Lower Marshall strata. Moser (1963), in a study principally on t h e Michi­ gan Formation, defined the Marshall sandstone in south­ western Michigan as the "True Marshall" which is the time equivalent to the lower part of the Michigan Formation. The strata between the stray sand and the Coldwater shale in the northeast, the "Marshall," is older than his "True Marshall." Therefore, Moser suggested there is an hiatus between the Coldwater and the Michigan Formations in the southwestern part of the Basin, and also the sand­ stone strata above the Coldwater in the northeast should be redefined and renamed. The relative, age of the Marshall at the Coldwater contact across the Basin apparently poses a problem unto itself and is beyond the scope of this present study. However, the nature of t h e Coldwater-Marshall contact is significant. Whereas a transitional contact exists in the east, a relatively sharp contact exists in the west. The uniform westward thinning of the Coldwater across 26 Michigan hardly suggests a major hiatus disconformity) (actually erosional implied by Moser that would be called upon to cut out the eastern type Marshall in western Michigan and place the considerably younger Mississippian sandstones (his "True Marshall”) superjacent to the Coldwater. Problems of Nomenclature and Correlation As previously cited, the Coldwater formation was named by Lane in 1893 for exposures along the Coldwater River in Branch County. Original description of the Cold- water shale (Lane, 1893) apparently included the Berea shale or the Sunbury black shale. However, owing to differences in lithology and color, the tendency since 1932 was to split these two shales into distinct formations. In 1900, in a report on Huron County, Lane discussed the geology of this County and compiled a geological column in which the Coldwater section was suggested as below: Coldwater Shale - Feet Blue and sandy s h a l e s ........................ 172 Lighthouse point conglomerate ............. 4 Blue shale (Chonetes scitulus cf. pulchella) 720 Black shale (Berea shale) 103 TOTAL 1,000+ 27 In the same year, in a geological study of Sanilac County, Gordon divided the Coldwater Shale of this County into three parts, shown in the usual chronological order: Coldwater Formation Feet - Forestville, blue shale ................. 100-200 - Richmondville, sandstone ............. 50-80 - Blue shale .............................. 200-250 Lane (1893) believed the Richmondville sandstone to be the Berea sandstone lying stratigraphically below the black bituminous shale at the base of the Coldwater shale. Gordon (1900) discussed that point and suggested the Richmondville sand should be occurring about 200 feet below the top of the Coldwater section in Sanilac County. The Lower Mississippian rocks in eastern Michigan comprise (ascending) the Bedford shale, Berea sandstone, Sunbury black shale, the Coldwater and Marshall formations. The sequence of rocks in Michigan, Ohio, Pennsylvania, Indiana and Kentucky are somewhat similar but different nomenclature was applied for these regions. In Ohio, the lower Mississippian rocks were referred to the Waverly "series" which included everything between the Ohio black shale and the Coal Measures strata. Prosser (1901) proposed the classification of the Waverly series as follows: 28 Waverly Series Logan formation (Andrews) Black Hand formation (Hicks) Cuyahoga formation (Newberry) Sunbury shale (Hicks) Berea grit (Newberry) Bedford shale (Newberry) The U.S.G.S. invalidated the Waverly "series” in 1960. The Cuyahoga formation was named by Newberry in 1870 for a rock sequence whose typical exposures w e r e located in the region of Cuyahoga River in Cuyahoga and Summit Counties, Ohio. The Orangeville, Sharpsville, Strongsville and Meadville are members of the Cuyahoga formation, with the Sunbury being considered only a basal unit of the Orangeville shale in this region (Dewitt, et a l ., 1954). Toward central and southern Ohio, the Black Hand was believed (Hyde, 1915) to be a member of the Cuyahoga and that the upper contact was placed at the base of the Logan formation. Initially, the Cuyahoga was used as a "group” in northern Ohio and northwestern Pennsylvania (Cushing, 1931); but in central and southern Ohio it was regarded as a "formation.” Gradually, divergent ideas on the stratigraphy of Ohio have developed. The m o s t striking point was the introduction of the Buena Vista sandstone into the stratigraphic column. Originally, thiB sandstone was placed at the base of the Cuyahoga shale, but Hyde (1921) suggested that the Buena Vista should be correlated to the Berne sandstone which formed the lower 29 member of the Logan formation. work on the ideas of Hyde Holden (1942) basing his (1915, 1921), Prosser (1912), divided the Cuyahoga formation into seven lithofacies, each facies in turn divided into varying members and submembers. In a recent work on the Cuyahoga formation in northern Ohio, Szmuc (1957) raised some submembers to member rank and proposed some new members with a classi­ fication comprised ot ascending order, the Orangeville, Sharpville, Strongsville (new), Meadville, Rittman, Armstrong, Wooster (new) and Black Hand (Table 1)• He considers the lower part of the formation to be Kinderhookian; the Meadville to contain mixed late Kinderhood-early Osage assemblages; and the upper part to represent the Osagian. Clastic sedimentB of the Cuyahoga formation are mainly fine to very fine sand, silt and clay. Coarser sandstones are predominant in the Black Hand member. Szmuc also suggested that the Cuyahoga sediments are shelf sediments and deltaic or bar sediments which were derived from an eastern source. Lower Mississippian rocks of Indiana and Kentucky are somewhat similar to those of Ohio and Michigan. Stockdale (1939) in his w o r k on the Lower Mississippian of the east-central interior, concluded that the clastic Borden group of Indiana and Kentucky is equivalent to the Waverly series of Ohio, and to the combined Coldwater and Marshall formations in Michigan. According to Stockdale TABLE 1.— Chart shewing Stratigraphic Names Applied to the Post-Berea Lower Mississippian Rocks. EASTERN PENNSYLVANIA (Colton, 1970) NORTH-CENTRAL PENNSYLVANIA (Colton, 1970) NORTHWESTERN PENNSYLVANIA (Szmuc, 1957) NORTHERN AND NORTH-CENTRAL OHIO (Szmuc, 1957) "Shenanqo" Formation Logan Formation Hempfield Member Vinton Member Shenanqo Member Allensville Member Burgoon ss. Mount Carbon Member Byer Member Berne Member Patton Red Shale Cuyahoga Formation o« 3 at u o § u 0 Cuyahoga Formation Black Hand Member Wooster Member Armstrong Member CL Rittman Member Beckville Member Meadville Member Meadville Member Sharpsville Member Strongsville Member Orangeville Member Sharpsville Member Orangeville Member Berea Formation Berea Formation 31 (1939) , the New Providence formation, a unit at the b a s e of the Borden group, is equivalent to the Cuyahoga formation, therefore to the Coldwater formation of Michigan. The stratigraphic relation of northwestern Pennsylvania and Ohio also raise an important problem. I. C. White (1880, 1881) suggested that his Meadville group with three units, the Orangeville shale, Sharpsville sandstone and Meadville shale, is apparently equivalent with the Cuyahoga in northern Ohio. Overlying the M e a d ­ ville group is the Shenango group with Shenango sandstone and Shenango shale (White, 1881). The Shenango sandstone was thought to correlate to the Logan formation in Ohio (Orton, 1882; and many others). However, in recent years, it has been regarded as the stratigraphic equivalent o f the upper part of the Meadville member of Cuyahoga and Medina Counties, Ohio (Szmuc, 1957). Farther east in Pennsylvania, the Pocono orthoquartzites have the stratigraphic position of the Lower Mississippian and because of the position superjacent to the upper Devonian Catskill red beds, the sediments are considered post-orogenic (Acadian) and therefore of Mississippian age. The relatively barren eastern Pocono apparently become "more marine" westward. Two faunal zones have been recognized and described by Bolger and Prouty (1953) from shales and sandstones considered "Pocono" on the bases of stratigraphic position and gross 32 lithoXogic comparisons. However, the faunas are not diagnostic but have forms conspecific with some o f the Upper Devonian Chemung and Lower Mississippian. The general lack of Productids and Syringothyrids adds to the uncertain nature of the fauna. The eastern Pocono has been referred to as fluviatile in origin (Pelletier, 1958) with a clastic and low rank metamorphic provenance farther east near the New Jersey coast. The weBtern Pennsylvania sequence would b e about intermediate lithologically between the coarser clastic eastern Pocono and the Michigan Basin Coldwater shaly terraine. Modifying effects of local structure on the Michigan Basin Lower Mississippian sediments is discussed under Paleogeographic Inferences. Correlation has been attempted between the lower Mississippian strata in Michigan and the Waverly group of Ohio. T h e first of such works dated back to 1900 based on the w o r k of Cooper. The Coldwater formation was apparently correlated to the rocks between the lower part of Logan formation, the Racoon shale, the Cuyahoga shale and the Buena Vista in Ohio. In the light of new information on Ohio stratigraphy, Cooper's correlation needs to be reviewed. In general, the Coldwater can be correlated to the lower part of the Pocono formation of Maryland and Pennsy1vania; to at least the four lowest members of the Cuyahoga in Ohio (Orangeville, Sharpsville, Strongsville and Meadville); and also to the New Providence formation 33 of Indiana and Kentucky. Regional correlation is generally based on the 1947 publication of the Mississippian Subcommittee of the Committee on Stratigraphy of the National Research Council (Table 2). The exact age of the Coldwater has long been a controversial problem. It has been assigned at times to the Kinderhook and/or Osage and even to the Devonian Chemung. Heller and others (1948) assigned the Coldwater and Lower Marshall to the Kinderhookian# and the Napoleon sandstone to a lower Osagian age. In 1951# Cohee con­ cluded that part of the Coldwater and the Marshall forma­ tions are of Osage. In a more recent study by Miller (1953# 1955) of the cephalopods of the Coldwater and Marshall# the upper Coldwater was considered of Kinderhook and early Osage age. In a study of Mississippian brachi- opods in Michigan, Oden (1952) concluded that species found in the Coldwater and Marshall formations are of Early Mississippian age but regional correlation of these two formations based on brachiopods are restricted because of lack of duplication of certain species in geographi­ cally removed collections. Camarotoechia huronensis var. precipua (Winchell) and Syringothyris pharovicina (Win.) were observed by Oden only at Lighthouse Point# in the upper Coldwater. On the other hand# the time-equivalent of Syringothyris c f . textus which was found in the quarry of the Wolverine Cement Company at Coldwater# Branch TABLE2.—RegionalCorrelationChart (afterWeller, J. M.,etal.. 1947). STANDARD STRATIGRAPHIC SECTION SOUTHEAST IOWA ILLINOIS BASIN WESTER) MICHIGAN EASTERN MICHIGAN SOUTH CENTRAL OHIO CENTRAL KENTUCKT Formation in Type Region Keokuk la, Michigan Fm Burlington Is Fern Glen Fa. Napoleon SS Lower Marshall SS Chouteau Is. Coldwater Fa. English River ss New Albany sh Maple Mill Cuyahoga Grit New Providence Sh. Coldwater Fa. Ellsworth sh Bedford sh Bedford sb Louisiana sh. Antrim sh (upper part) (Sweet land creek) Underlying Formation Cedar Valley Is M. Dev. Dev. L. Antrim sh Antrim sh upper part) L. Ohio sh. L. Ohio sh 35 County also cannot be obtained exactly because of its recognized wide range in stratigraphic time Lane and Cooper (Oden, 1952). (1900) divided the Coldwater in Huron County into three "paleontologic zones": The Rock Falls series with Chonetes scitulus; The Lighthouse Point series with Syringothyris pharovicina, Proetus missouriensis and numerous spiriferids and Schizodus; and the Huron City series with Rhynchonelloids and Productids. The faunas as recorded by Lane and Cooper are shown below for comparative purposes: The Rock Falls series: Chonetes scitulus Conularia gracilis Productus blairi Spirifer centronota Spirifer Shumardianus Productus newberryi var. annosus Streblopteria media Phaethonides spinosus Syringothyris, lamellibranchs, crinoids The Lighthouse series: Spirifer subattenuatus Spirifer medialis Spirifer huronensis Syringothyris pharovicina Spfri'fera ? Cc f . Athyris) insolita Eumetria (?) polypleura Camarotoechia huronensis (Rhynchonella) Or this v'anuxemT Derhya ya crassa Totthis crenistria) 6rthls iowensis? 36 Other genera: Xviculop Spirifer deltoldeus Ayiculdpecten areolatus , (Crenipecten?) Edmondia c f . blnumbonata Sphenotus aeolus Hall Schi 2 Qdus triangularis SchlzodUB b l n u m b o n a t a c f . aequimarginalis Prothyris meekl Proetus missouriensis Orthocera's' barquianum The Huron City series; Camarotoechia (Rhynchonella) camerifera Small Productid, Scolithus, Schi sodus triangularis, Myalina, Sphenotus? / Crenipecten wincbelli Microdon reservatus Description of the Coldwater Formation General As previously cited, the lower conbact of the Coldwater is rather distinctive though based on different criteria in western and eastern Michigan, contact of this formation, because of the lithologic similarity to the overlying Marshall sandstone, is not easily defined and appears to be gradational. The upper contact is placed somewhat arbitrarily and some unavoidable errors may have been introduced into the i$opach map, especially in eastern Michigan. As shown in Figure 4, the thickest part of the Coldwater (1200! feet) is concentrated toward the north­ eastern part of the Basin in Iosco and Arenac Counties in 37 the Saginaw Bay area; howe v e r , the deepest part of the present Basin (see structure map. Figure 3) received only about 1000 feet of sediments. Thus the Coldwater depo- center and present structural center do not coincide. Assuming the area of maximum subsidence in Coldwater time received the thickest sediments (1200 feet) the basinal center as seen on the present structure map must have shifted its position in post-Coldwater time. Thicknesses of about 1000 feet occur throughout the central portion of Michigan from Mecosta and Gladwin Counties to I o n i a , Eaton and Jackson Counties. The formation thins gradually toward the west, where less than 550 feet in thickness extends from Lake County to the western margin of Oceana and Muskegon Counties. It is apparent that the Coldwater formation thickens geometrically to the east where the coarse elastics are prevailing. The westward thinning of the Coldwater reflects either an overlapping on higher structure in western Michigan or because of thinning away from the eastern source. It appears clearly that the first possibility is unlikely as the stratigraphy indi­ cates westward convergence as opposed to the loss of lower beds expected in an overlap situation. south structure Also the north- (Figure 2) in central Michigan mentioned earlier as effective in influencing the pre-Sunbury sedimentation, showed no influence on Sunbury and Coldwater sedimentation. The South Michigan shelf, 38 suggested b y LeMone (1964), during the post-Antrim pre- Sunbury interval was ineffective on Coldwater sedimentation. In the western and northwestern part of Michigan the Coldwater is mainly shale with some impure carbonate rocks and is thinner than to the east, both factors favoring an eastward source. Reference to the structure and isopach map (Figures 3 and 4) show both the structural and depositional center of the Coldwater to be in the eastern part of the State, near Saginaw Bay. Prouty (1971) considers that the change in the structural center and depocenter to the present central location in Southern Michigan to have occurred before Grand River (Meramec) Mississippian time, and in response to extrabasinal orogenic stresses from the east, probably the Appalachians, and reflected in Bhear couples manifested as lateral faults and shear folds (Figure 1). Coldwater isopach lines infer that the Michigan Basin at this time was beginning to "fill up" with rapidly accumulating sediments reflecting at least partly the activity east of the Basin. In general, the Coldwater Formation grades laterally from the east towards the west. The sandy shales and fine-grained sandstones which are prevalent in the east gradually change to silty shales and shales in the center of the Basin and then into calcareous shales in the west. Several beds of dolomite and limestone are observed along 39 the western edge of Michigan. It is believed that the facies change is a continuous gradation and that the lateral rate of change is gradual. Despite the gradual change it appears difficult to trace lithologically any beds or units for appreciable distances across the Basin. Careful study of gamma-ray neutron logs show, however, that apparent unit-by-unit correlations can be obtained only between close control points (Figures 7, 8 and 9). The writer has studied some radioactivity logs available at the Geology Department, University of Michigan, and recognized that the "Coldwater red rocks" and the "Coldwater lime" may b e traced laterally for long distances (Figure 10). The lower contact and also the upper contact, except in eastern Michigan, were also readily defined. The dolomite in the west and the sandstones in the east intcrflnger with the main shale body. However, some of the sandstones and dolomite units are considered lenses as opposed to offshoots or tongues of the principal bodies. As the rocks of eastern Michigan consist almost entirely of terrigenous clastic materials, a regional sand percentage map (Figure 10) therefore was constructed to examine the sand distribution pattern. Units defined as either sand or shale in the sample study were assigned 100% sand or 100% shale values. Sandy shales or shaly sandstones were recorded by their relative percentages. 40 EXPLANATION FOR FIGURES 7 , 8 8 9 Sandstone, micaceous .V.V. #w « » Sandstone, conglomeratic Sandstone, shaly Shale Shale, sandy Shale, dolomitic Dolomite "Speckled" dolomite Dolomite, glauconitic oVo Fossiligerous \s00- 53 1R Chert Red rock No sample r i— i i n i ■ m Limestone, pyritic GraUt Stoaw ue 9H1WIJ sh IE04 Pmlini p„, gj96 Kent BNIOWU Prnt 591 Ktnt # 7NIJWJO Muftoqon ft"7010 fNMVM Pm 1(550 / / tctu 10 ■ 1 r m. Figure 7.— Stratigraphic Cross-section AA twrnnrr Midland taballaHM60S3 fm 11386 Clara I7N 50I4 Pm 10639 L6H.!!? ! Pm H046 • Bau » Tuscola Sanilac I3NI0E09 MMBEI4 Pm H04« ftn 12158 P^ 321S * ... '-•3. Otcaola. 1R WN3«W KL' ri' ?S ITH100JO Pm 10504 ITMtSWIC 1 *S ha r m IJ TI ^ * -:•> M Sy Figure 8.— Stratigraphic Cross-section BB' se au t •tfc M • Bornj 7 4U 8W 0I B arrj Calhoun 3S4M K Rn 97*5 uiutu ■jt Qw m l5NKUt> Am war * Nmmmoo > UN MM10 Mu»k«gon fin 13570 9“ fin 11550 OttOiMi CN Pm 13*14 5704 •C A L I kv CNMMT 1I tL v: Y _Tt X '!— r -^2 B ____ IU M IU M T u u n m Figure 9.— Stratigraphic Cross-section CC & 8 .. in r N ii — ty *■ Mohtulm Ncmno Ncwno H s m t u l m Em t n t IIH5N0S UN401IS f t n 240ll r m l S 4B3 UNllltf 15 ftnaaM Gkatwt P m ZJ 7W hum Figure 10.— Cross-section DD' (Gamma ray-neutron log control) 45 Silt grade size grains were, placed with shale grade in this study. The sand percentages were then determined by the following procedure: total of sand thickness j !_, sand p e r c e n t a g e ------- total thickness--- Lithologic components other them just sandstones and shales are important to the lithologic composition of the Coldwater Formation. As carbonate rocks are important constituents of the western Coldwater sequence, clastic percentages were computed to demonstrate the variation of clastic and non-clastic materials and are displayed in Figure 11. Although, three lithologic components— sand­ stone,- shale and carbonate rock— are present in the Coldwater one might consider a triangle facies display to indicate the component percentages. However, because the facies change is rather uniform, with sandstone confined mostly to the east and the carbonate rocks— dolomite and limestone— are prevalent only in the west, the writer preferred display by isopleths. The sand percentage decreases gradually westward, from a maximum of about 30% in the Coldwater depocenter area and also in Tuscola, Genessee and Lapeer Counties, to about 1-5% over most of the central part of the Basin (Figure 11). The western extent of sand forms the boundary of the eastern and western facies. It is significant to note 46 MICHIGAN COLDWATER FORMATION Sand Percentage ■ t_. •«.*«» «'l i Figure 11 M Je a — 47 that the sand percentage is highest where the Coldwater is thickest and could be interpreted to mean that the distribution of coarse clastic sediments, in addition to the greater proximity to the inferred source, is related to the subsidence of the Coldwater depocenter. In this eastern part of the Basin the higher quartz sand content was likely close to the shore, and the water was likely shallower, with a high energy wave and current environment with higher potential conducive to the destruction of organic matter in the sediments, effecting the color of the sediment. Also, towards the east, the mica content . . increases, with large mica flakes also increasing at the same time with the quartz sand content. More concerning the clay minerals will be covered later. Likewise, the clastic percentage also decreases westward (Figure 12). Total 100% clastic content is located in eastern and central Michigan. In western Michigan the clastic percentage decreases to about 60-70%. Moreover, the approximate parallelism of the facies gradient and the isopachous line in the west can be interpreted as indicating that the contribution of find muds is reduced in quantity because of distance from source area and that the lime and lime muds increase. The color of the Coldwater sediments varies from dark gray to light gray and red. The distribution pattern of shale color is illustrated in the shale color map 48 i M ICHIGAN COLDWATER FORMATION I Clastic Percentage - (3a. HtmE&BSKBI s iis iiir iiiiig Figure 12 49 (Figure 13). Dark gray shales, including dark shales, exceed the light gray shales in total thickness. They are located in the central part of northwestern Michigan, covering the area from Roscomon to Muskegon Counties. The darker color suggests reducing conditions of poorly aerated deeper waters. It is also possible to interpret that low permeability in the homogeneous fine-grained shales, which deposited far from source areas, account for the development of reducing environments. From this region, the shale color becomes lighter towards the west, southwest and the east, where light gray exceeds dark gray. It is difficult to state how much "grayness" defines "light" gray and "dark" gray. However, for the sake of some standardization, the writer used the Rock Color Chart (1948) and dark gray is apparently close to SYR N2-N3 and the light gray close to 5YR N5-N6. Northeastern Michigan contains a significant proportion of red rocks. These reds mostly are confined to the upper part of the Coldwater Shale, limited from 500 feet below the top to the top of the formation. The lowest zone of red siltstones and shales can be traced as the most persistent zone. Between this zone and the top, there exists three or four other red units of sandstones and shales. The areal distribution limit of these upper red zones in the Coldwater Formation is displayed in Figure 14. It is evident that a major influx of red 50 MICHIGAN COLDWATER FORMATION Shale color MB vma mi aim fefflMM) UMT MtT □ E S I *v«e»»p Figure 13 51 MICHIGAN COLDWATER FORMATION Red Rock Facies I f Sg|®l 8fe'?ES5S®l5lr-S >3 Figure 14 52 sediments entered the Basin from the east and/or the northeast. The red color suggests well-oxidized, perhaps highly-aerated, shallow-water environment, during the late Coldwater deposition in this region. It is possible to believe that the shoreline should be very close to the Saginaw Bay area at this time. A study of the environmental implication of fossils as reported in the literature from eastern outcrops and the meager information gleaned from fragmented fossils in subsurface samples play some part in the sedimentary environmental interpretations and will be discussed later. The above information leads to the conclusion that the Coldwater elastics were derived from a generally north-northeastern source, or sources. The elastics probably were derived from the Laurentian Highlands and transported to the Basin area by a river system perhaps not unlike that to which the Berea-Bedford deltaic system was attributed in Late Devonian-Early Mississippian time (Pepper, et a l . , 1954)• Thus a prodelta model is conceived in the area east of Michigan and will be discussed more later. Special Sedimentary Features The most striking characteristic of the Coldwater shale is its lateral gradation from the east towards the west. However some special sedimentary features such as the clay ironstones, the red rocks, glauconite are also 53 so important: that they could add some information to a better understanding of the Coldwater shale* Concretions.--During the early stage of this s t u d y , the writer visited the type locality and some other exposures of the Coldwater in Branch and adjacent counties. At the time of the visit, these exposures including two old abandoned quarries— the Peerless and the Wolverine Portland--were in such poor shape that the writer could not recognize the section as described by Wooten in 1951, much less the type description by Lane (1893). Generally, bluish-gray shales and few clayironstone concretions were observed in most places. The Peerless cement quarry (NEJs sec. 16, T. 5S., R. 7W.) presents a few feet of somewhat thick-bedded, arenaceous, greenish-gray shale. The clay-ironstone concretions, which G. M. Ehlers (1916) called "intra- formational conglomerates," occur in zones along the bedding. The individual concretions range from h of an inch to as much as 4 inches in diameter. They are often nearly spherical, though some are elongate o r of crescent­ shaped form. Hematite is often in the center surrounded by concentric gray silty claystone. There also includes some "pebbles," being angular or rounded, composed of light gray calcareous claystone and embedded in the i \ greenish gray ferrunginous shale. 54 In the abandoned Wolverine Portland Cement company quarry (NW%, sec. 32, T. 6S., R. 6W) the cobble-sized clay-ironstone concretions are concentrated near the top of a 19 foot-section in gray silty shale. The gray clay­ stone in the center is surrounded by concentric limonitic shale layers. In this quarry Wooten (1951) described several horizons of concretions which varied through a range of sizes. The "canon ball" horizon refers to concretions measuring about 6 inches in diameter, which often contain fossils as nuclei; whereas, the "pillow" horizon, stratigraphically below the previous horizon, indicates those larger in size (18" x 12" x 3") often show septarian structures and no fossil nuclei. Although no fossiliferous beds were observed in place a number of float blocks were observed by the writer to contain chonetid brachiopods (probably Chonetes scitulus Hall) and some limonitized crinoid stems. It is evident that some of these concretions are secondary, because the bedding can be seen passing through these concretions. As all materials are broken to small chipB during the drilling process it is impossible to recognize the size and shape of the concretions in the well-cuttings as well as to locate a special stratigraphic zone of clayironstones. However, the hard brown iron "shale" found in well cuttings, as suggested by Hale (1941), apparently 55 are drilled-up concretions. During the course of lithologic study, the writer found these hard brown shales mixed with the gray shale in many of the wells studied. However, these materials are apparently abundant in the southwestern part of the Basin, especially in Branch, Kalamazoo, Barry and Ottawa Counties section CC*). (Cross- In some wells, these hard brown shaly materials may comprise about 70 to 80 percent of the 100foot thickness of shale, apparently indicating a rich concretion zone. Some fragmented fossils, mostly brachio- pods, not unlike some at the type locality (Chonetes scitulus cf. pulchella) are usually found within these zones. It is apparent that the concretion zones are con­ centrated in the upper part of the Coldwater formation, and to that extent are of some limited stratigraphic significance. Coldwater red rock.— coincident with the base of the Coldwater formation is a distinctive key red bed which is traceable in the subsurface over a large area within the B a s i n . - The informal term for this bed is the "Coldwater red rock." Typically, this unit is pink, yellowish-red and deep red. The Coldwater red rock varies irregularly in thickness from a few inches to as much as 50 feet. The thickest part of this bed generally occurs in the western 56 part of the Basin, where there exists lithologically two different units of red. The red shale locally lies above the red dolomite and/or red limestone sect ion A A ' , wells 1, 2 and 3). (Figure 7, cross- The limestone is aphanitic with some secondary crystals of clacite; the dolomite is aphanitic to finely crystalline. There is no evidence of an areal distribution pattern for the lime­ stone or dolomite. The important fact is that this key bed grades laterally across the State. CC' As shown in the cross-section (Figure 9) from well 1 to well 6 there are red lime­ stone and dolomite bedsj wells 7 and 8 have calcareous shale; and well 9, red shale. This gradational character is also observed in cross-section AA' BB' (Figure 7) and (Figure 8). The facies distribution of the baBal Coldwater red rock is illustrated in Figure 14, which is based on the well samples studied by the writer and also on the data from published wells. Red dolomite and limestone facies occur in the counties on the western margin of the state; the calcareous shale facies in the north central a n d ’ south central parts of the Basin; and to the east, red shale and silty shale. A non-red area is located in about central Michigan (Figure 14). As illustrated in the cross-section B B * , wells 4 and 5, about 15 feet of non-red dolomite have been observed directly above the Sunbury shale, and 57 is -the same unit as the red dolomite farther west. Based on this observation, the writer believes that the red sediments likely may have deposited in this area but transformed to gray because of some environmental factor as a change to reducing conditions. Xt is perhaps more than coincidental that this general area is also the same where darkest shale occurs (Figure 13) lending additional support that reducing environment prevailed in this area. Similarly, in some localities the red shale occurs as much as 40 feet or more above the Sunbury shale. Xt is possible that the gray sediments between the Sunbury and red bed once were red. On the basis of X-ray diffractograms of red samples, Assez (1967) concluded that hematite is the main pigment of the red unit. Hale (1941) has suggested that the source of red pigment is from the landmasses on the north and west, where the Precambrian iron deposits are abundant. The writer believes if there is any red pigment from these directions, it is not the major source. Based on the lateral grada­ tion of this bed, the writer suggests the source of this hematite is more likely from the east and/or northeast. Moreover, near the top of the formation another series of red sandstones and siltstones occur only in the northeast part of the Basin. These apparently grade to gray silt- stone and shale to the west, again suggesting the source 58 of red pigment in Coldwater time is from the east and northeast. It is possible that the red color may have originated at the site of deposition due to shallowoxidizing conditions as has been envisioned for other red-bed units (Walker, 1967). However, either being primary in origin or being formed in place, the red color proves at least the well oxidizing environment at the beginning of the Coldwater deposition as opposed to the reducing environment during the Sunbury deposition. The distribution of the red rock or greenish-gray facies appears related to an oxidizing environment (ferric) or reducing environment (ferrous) respectively, existing in various parts of the basin at various times. Just what were the factors in controlling the oxidizing or reducing environments is not altogether clear. From the isopach and/or structural maps in studies of earlier rocks as the Upper Cambrian (Prouty, 1970) and late Devonian (Asseez, 1967) reducing environments appear tied in with deeper, isolated "pockets" in the sea floor and can be related to thicker areas revealed in the isopach maps. Some sug­ gestions for shallow water oxidizing environment are noticed in the western part of the Basin where the carbonate, both limestone and dolomite, are also hematitic and form the red rock. This shallow area also may have J.X been a factor in the concentration of Mg to bring about dolomitization in the carbonate environment. 59 Glauconite.— A remarkable feature is the presence of glauconite which is closely associated with the dolomite in the western part of the Basin. Hale (1941) described the glauconite as abundant in the "speckled dolomite" (facies) and the crystalline dolomite (facies). The writer observed glauconite grains also in the greenish-gray shale immediately above and below the "Coldwater lime" horizon. The glauconite graihs are often nearly spherical with their diameters from .2 mm to 1 mm; although some are elongate or long and thin, prolate forms with a length ranging from .5 m m to as much as 2 mm. There is no evidence of an areal distribution pattern for the size and shape o f the glauconite. Variable sizes and shapes are observed in the same piece of the well cuttings. This fact is likely to require one to reject the idea that these glauconite grains are reworked materials. tion Also, no specific distribu­ (abundant or rare) of the glauconite is indicated. Many investigators have long believed that glauconite is formed during marine sediment diagenesis; and that it is derived from clays, micas and feldspars. According to Cloud (1955) glauconitization is favored by these physical conditions: in marine water with normal salinity; in a slightly reducing condition in the presence of decaying organic materials; in an area of slow deposi­ tion; and in cool water. 60 These physical conditions may not totally satisfy the formation of glauconite in the "Coldwater lime," but the proposed conditions above may be suggestive of the environmental conditions at the time of "Coldwater lime" deposition. Chert.— A few pieces of chert were observed in the "speckled domomite," mixing with the glauconite grains and dolomite grains. color. The chert is aphanitic and light gray in In well cuttings, the chert content is not so high that one would assume it to represent chert nodules or chert layers. The writer calls attention to this occur­ rence of chert in the "speckled dolomite," but it iB not a quantitatively important feature. "Speckled Dolomite" .— "Speckled dolomite" was used by Hale (1941) referring to an impure carbonate which con­ sists of light gray dolomite matrix with embedded grains of light brown dolomite. The dolomite grainB yielding a somewhat pelletoid or pseudo-oolitic texture and ranging from 0.2 to .05 mm in diameter float in a dolomitic matrix which is argillaceous and sometimes silty. This "speckled dolomite" is a part of the "Coldwater lime" wh i c h forms a marker zone in the western part of the Basin. Glauconite and chert are observed in this calcarenite. As previously cited, the Coldwater Formation is divided into a western and an eastern facies (Monnett, 1948) 61 based mostly on the quartz sand content. The writer agrees with Monnett*s idea and prefers to use his facies terms. Western Facies The western facies consists almost entirely of gray shales with a minor amount of carbonate rock. marker zones are defined in this facies: Two the "Coldwater red rock" at the base; and the "Coldwater lime" located about 200 feet below the top. Several exposures of the Coldwater western facies are observed in Branch and Hillsdale Counties, including the type locality along the Coldwater River in section 10 of Union Township. In a study of the Coldwater shale in the type locality, Wooten (1951) compiled a list of exposure localities and also briefly described these localities. The location of the exposures of the Marshall and Coldwater formations in Hillsdale County can be found in the report of Hillsdale County written by Helen M. Martin (1957). The writer had an opportunity to visit some of these exposures where mostly gray silty shales and shales with abundant clay-ironstones were observed. These shales were quarried for cement and brick materials. High silica content is a remarkable characteristic of the Coldwater shale in the type area. A chemical analysis of a shale sample quarried by Peerless Portland Cement Co. 62 (NW% section 15, T. 5 S., R. 7 W.) was reported as follows (Brown, 1924): Silica (Si02) Alumina (Al20 3) Iron Oxide Lime . . Magnesium (MgCO^) Sulphur (SO^) . . . (Fe20 3) (CaCO^) . . 64.56% . 22.00 . . 2.96 • . . .60 . . . none . . . . trace O r g a n i c .....................9.88 The basal part of the Coldwater western facies is composed mainly of shales. The thickness of shale in between the key red bed and the Coldwater .lime marker bed increases from the west towards the center of the Basin showing the convergence westward (Figure 7). -Referring to the isopach map (Figure 4), the thickness of the formation also increases from about 550 feet in the western margin counties to about 1050 feet in the center of the Basin. The "Coldwater lime" marker zone is a specific feature of the Coldwater facies. Hale (1941) described four types of dolomite belonging to this zone: speckled dolomite without glauconite; with glauconite; (1) (2) speckled dolomite (3) crystalline dolomite with glauconite; and (4) crystalline dolomite without glauconite. 63 Based on the fact that the western outer rim of this horizon is much thicker, Hale (1941) concluded that a "trough trending northwest and southeast received the deposition of the speckled dolomite sea." The "Coldwater lime" is located about 250-350 feet beneath the formation top. Its thickness ranges about 50 to 80 feet in western margin counties and thins gradually towards central Michigan where it grades laterally into gray shales. A few "lenses" of the crystalline dolomite were observed in west-central Michigan, especially in the northwest where they are associated with pyrite and darker gray shales. The upper part of the Coldwater western facies is somewhat similar to the lower shale. Reddish brown hard shale observed in the upper part of shale body probably came from a drilled clay-ironstone concentration zone. This upper part shale is siltier than the lower part with more mica flakes. It apparently proves that in upper Coldwater time more clastic materials spread toward the west and that there was regression and a prot grading shoreline westward. Eastern Facies Eastern Michigan Coldwater consists chiefly of sandy shales and fine-grained sandstones. Several exposures crop out along the lake short of Huron and Sanilac Counties. Napoleon Sandstone and Lower Marshall 64 Sandstone are exposed in the western shore and the northern part of Huron County notably at Little Oak point, Hat Point, and Point Aux Barques. Toward the south, shale and sandstone of the Coldwater Formation crop out at Port Hope, Harbor Beach, White Rock in Huron County and at Forestville and Richmondville in Sanilac County. Land (1900) and Gordon (1900) described those exposures and also compiled the geological column for Huron County and Sanilac County, respectively. The writer intends to review these geological sections and then correlate them into the subsurface stratigraphy. East of the Burnt Cabin Point, about 25 feet of fine-grained sandstone are exposed, the Grindstone Beds, which grade downward into a blue shale. Lane (1900) placed the Marshall-Coldwater contact on top of this blue shale. This shale is about 30 feet thick becoming increasingly sandy below. A series of alternating beds of sandstone and blue shale are exposed along Willow River, Huron City and at the Lighthouse. These sections were described and measured by Lane (1900). 65 Section of Coldwater Strata exposed at Willow River, Huron City and the Lighthouse (after Lane, 1900): Feet Inches From 89 feet below the top of Coldwater Shale. Dirt Sandstone, red (Rhynchonella, Productus, Pleurotomaria, e t c .) Barren Shale, sandy Shale, blue, sparingly fossiliferous Shale, blue, without fossils Shale, arenaceous 6 3 3 6 3 2 - From 156 feet below the top. Shale, blue Sandstone, calcareous Shale, blue, sandy 11 3 3 3 From 170 feet below the top. Sandstone (Schizodus) S h a l e , blue Sandstone, conglomeratic, pyritic Shale, blue (Productid, Spirifer, Trilobite larvae (?) corresponding forms observed in Romingerina julia zone 1 3 4 3 8 12 The conglomeratic sandstone at about 170 feet below the top of Coldwater Shale is called Point Aux Barques Lighthouse Conglomerate. This nomenclature is easy to confuse with the Point Aux Barques Sandstone or Lower Marshall sandstone which occurs considerably above the Lighthouse Conglomerate. The Point Aux Barques sandstone is massive, cross-bedded and fine to coarse-grained. About 283 feet below the top is a blue sandy shale which is exposed along the shore south of Port Hope and at the mouth of Diamond Creek. 66 Toward the south, shales and arenaceous shales with carbonate of iron are exposed near Harbor Beach where Lane (1900) described Chonetes scitulus of. pulchella, Productus loevicosta, and Conularia gracilis. Blue shale and sandy shales with Chonetes also are exposed at Rock Falls and White Rock. They are about 450-500 feet below the top of the Coldwater Shale. In Sanilac County, shale and sandstone are exposed at Forestville and Richmondville. The Forestville shale is thinly laminated and interbedded with fine­ grained micaceous sandstones. The Richmondville sandstone refers to an outcrop of sandstone exposed near Richmond­ ville, Sanilac County. Gordon (1900) described it as 50-80 feet thick of sandstone and placed it within 100-200 feet below the top of the section (the Forestville blue shale). Based on the geological column of Gordon (Figure 15) the maximum thickness of the Coldwater Formation is about 500 feet in Sanilac County. This thickness is too thin for the full Coldwater section (see Coldwater isopach map, Figure 4), and the glacial drift probably rests on the truncated upper part of the formation. Comparing two geological columns of Lane and Gordon (Figure 15), the writer believes that the Forestville shale at the bottom of Lane's column is equivalent to the 67 HURON COUNTY (Lane, 1900) Grindstone quarries MARSHALL ysESg&i Lighthouse conglomerate COLDWATER SANILAC COUNTY ( Gordon,1900) Glacial and recent />:Fdrestville Rock F a lls *' Richmondville Forestville COLDWATER m m SUNBURY BEREA m m BEDFORD ANTRIM {Pham Chung, 1973) Figure 15.— "Standard Section" of Eastern Coldwater. (after Lane, 1900; Gordon, 1900) 68 Coldwater at the top of the section (the Forestville shale) of Gordon's column. The Forestville blue shale is 500 feet above the Sunbury black shale and 550 feet below the top of the Coldwater. It is apparent from the isopach map (Figure 4) that the thickness of this forma­ tion should be about 1000-1050 feet thick in Huron and Sanilac Counties. The Richmondville sandstone, in terms of stratigraphic sequence (subsurface), should be close to the base of the formation, or about 200 feet above the Sunbury black shale. The combine of these two columns tied in according to Figure 15, can be considered a "standard section" for the Coldwater formation in east Michigan. Near the top, the Coldwater is sandy with some coarse elastics (the Lighthouse conglomerate) then followed downward by interbedded sandstones and shales (Harbor Beach, White Rock). The Formation is somewhat shaly at Forestville, becoming sandstone (Richmondville) and blue shale towards the base. However, the writer recognizes the difficulty in correlating the "standard section" into the subsurface section. As previously stated, the Coldwater formation grades laterally across the State. No lithologic criteria could be used with con­ fidence to subdivide the formation into specific members; and no one unit can be traced all the way across the state. However, as indicated later, the east and west extremes can be roughly tied together by use of several geographically overlapping data planes. 69 As shown in Gordon's geological column in Sanilac County, fine-grained sandstone exposed at Richmondville is about 200 feet above the black shale. The basal part of the eastern facies consists mostly of gray shales and fine­ grained sandstones. The writer suggests that these sandstones in the subsurface may represent the westward extension of the sandstones exposed at Richmondville, Sanilac County. Newcombe (1933) stated: In wells, the Berea has frequently been mistaken for sandstone beds in the lower part of the Coldwater shale. These layers resemble one another strikingly and may have been derived from similar source. The areal distribution of the sandstone of the Coldwater basal part is shown in Figure 16. It is very fine-grained, micaceous, white to light-gray sandstone. The grain size is about 1/8-1/32 mm in diameter in Huron and Genessee Counties and grades into silt size in Clinton, Saginaw and Midland Counties. The medial part of the Coldwater eastern facies composes chiefly of gray shales and silty shales. The thickness of this medial shale ranges up to 400-500 feet thick in most parts of eastern Michigan. These gray shales are probably equivalent to the shales exposed at Forest* ville, Sanilac County. The upper part of the Coldwater eastern facies is very characteristic. sandstones and shales. It consists mostly of the interbedded This part has a higher quartz sand 70 L r Pham Ckunj, Figure 16.— Aeral Distribution of the "Richmondville" Sand 71 content than the lower part of the formation. As many as three or four red zones of sandstones and shales are observed. However, it appears difficult to trace these zones for long distances and they probably grade laterally into gray sand­ stones and shales. One or two conglomeratic sandstone beds at about 700-800 feet above the Sunbury are observed in Huron, Sanilac Counties but the writer cannot trace their extent because of lack of well samples in this area. It is also noted that these strata are very micaceous with large flakes observed in the sandstones. In general, the Coldwater eastern facies cannot be divided into viable members but three gross lithologic types exist. The subsurface data is somewhat similar to the outcrop data compiled by Hale (1900) and Gordon (1900) in Huron and Sanilac Counties, respectively. Clay Mineral Analyses Review on structure of clay minerals* .— One-third of the mineral composition of the average shales is clay minerals. minerals Clay minerals are referred to as a group of with a particular chemical composition and crystallographic structure. These minerals are described as hydrous aluminum silicates with some adding and replace­ ment of the aluminum by iron and magnesium. * After Grim, 1968. Structurally, 72 all crystalline clay minerals belong to the phyllosilicate group which has sheet structure with a hexagonal pattern somewhat like that of the micas. Two structural units are involved in the clay structure: one is silica tetrahedral layer (SiO^) and the other, octahedral layer (gibbsite and brucite). The thickness of the octahedral layer and the silica tetraO 0 hedral layer is 5.05A and 2.1A, respectively. With the exception of the allophane clay minerals which are amorphous to X-ray diffraction, the classification of clays is based on the possible combination of the tetra­ hedral and the octahedral units. The kaolinite group is classified as a two-layer (1:1) type which is formed by the link of an octahedral sheet to a silica tetrahedral sheet. The first order O spacing (001) of the kaolinite is 7.15-7.20A. The illite group is structurally represented by an octahedral sheet intercalated between two silica octa­ hedral sheets (2:1). Some of the silicon in its structure are replaced by aluminum, then potassium will be added to balance its charge. Illite is a 11non-expanding lattice" o clay, and its first order spacing is about 10A. Montmorillonite is also a three-layer (2:1) type, like the illite group. It is referred to as an "expanding lattice" clay, because the water and other molecules can be adsorbed, causing swelling in the .c-direction. Its 73 swelling character is useful in identifying montmorilIonite with X-ray diffraction. O Q Table 5 shows O spacing is 13-15A, 18A and 10A Mg-Glycerol treated and that its first order corresponding heated sample/ to untreated/ respectively. The chlorite is a regular mixed-layer type which consists of three-layer with an interlayer brucite sheet. O Its first order spacing is 14A. Clay mineral analysis of the Coldwater was under­ taken to determine if the various clay minerals could be correlated with lithologic types and the general facies relationships. Sample treatment and analytical met h o d s .— There were no available cores so well cuttings were used. wells Eleven (Table 3)/ with representative basinal spacing were selected for clay mineral analyses. Samples representing 5 or 10 feet intervals were contained in vials. About one quarter of a gram was taken from each vial to represent nearly one-third of the total depth of each well. Thus, three composite samples were obtained from each well studied even though no attempt was made to divide the Coldwater shale into a three-fold formation. After initial fracture in an iron mortar, samples were further dissaggregated mechanically and ultrasonically and transferred to a 1000 ml graduated cylinder. Then, it was filled with distilled water until the volume was exactly 1000 ml and agitated vigorously with 74 TABLE 3.— List of Well Samples Used for X-ray Experiments. Permit Location 11333 SW-15 T.24N.R3E 1A: 700-1000' 2A: 1050-1400' 3A: 1450-1850' 7462 SE-13 T19N.R3E 2A: 550- 810' 2 B : 820-1110' 2 C : 1120-1510’ 9275 NW-14 T14N.R12E 3A: 3B: 3C: 12612 NE-33 T10N.R7E 4A: 450- 800' 4 B : 805-1140' 4C: 1150-1495' 9215 SE-25 T20N.R3W 5A: 1530-1900' 5B: 1940-2270’ 5 C : 2290-2500' 12130 NW-15 T9N.R1W 6A: 1045-1280' 6 B : 1300-1700' 6 C : 1720-1920' 9987 SW-22 T4N.R1W 7A: 950-1280' 7B: 1300-1600' 7C i 1620'1950' 9765 SW-14 T3S.R4W 8A: 8B: 80: 7381 SE-24 T2-1N.R9W 9A: 1750-2000' 9 B : 2050-2250' 9C: 2300-2450' 8998 SW-20 T16N.R11W 10A: 1600-1730' 10B: 1750-1950' 10G: 2000-2200' 10596 SW-12 T8N.R11W 11A: 800-1100' 11B: 1150-1350' 1 1 C : 1400-1650' Sample 335- 600' 625- 900' 925-1300' 300- 5 5 0 ’ 570- 900' 920-1250' 75 a stirring rod. The <2y fraction was siphoned off after 24 hours settling at the 10 cm depth. The cylinder then was refilled with distilled water and the same procedure was repeated. A few cubic centimeters of clay suspension were allowed to settle on a ceramic plate so that most of the flakes were oriented parallel with the plate. The liquid portion was drawn through the plate by means of a vacuum procedure. The oriented sample was leached with 3 incre­ ments of 0.1N MgCl2 , then rinsed with several increments of water, 10% glycerol by volume. Samples, after successively drying in air and in a dessicator over CaCl2 , were ready for X-ray as a magnesium saturated, glycerol solvated, oriented aggregate (following the method of Dr. Max Mortland, Department of Crop and Soil Science, Michigan State University). After the first X-ray taken, samples were con­ tinued to b e treated following the flow-sheet procedure shown in Table 4 for total clay mineral composition. The cation saturation was varied by passing three increments of 0.1N KCl solution through the plate, then rinsed with distilled water. After heating the plate to 100°C for two hours, the sample was X-rayed as a potassium saturated aggregate. A third and a fourth X-ray w e r e run after the sample was heated for two hours at 300°C and 550°C, respectively. 76 TABLE 4.— Plow-sheet of X-ray Procedure. SAMPLE Dispersion Settle (24 hrs.) Decant SUSPENSION RESIDUE Deposit on ceramic film Leach (3 incrememts IN Mg-Gly) Rinse (Dist. I^O-lOfc Gly) Dry X-RAY (room T®-dessicator) (1st) Leach (3 increments IN KC1) Rinse (Dist. Water) Heat (2 hrs. +110°C) X-RAY (2nd) Heat X-RAY (3rd) Heat X-RAY (2 hrs. +300°C) (2 hrs. +550°C) (4th) Dispersion Settle (24 hrs.) Decant Suspension Residue 77 The X-ray diffraction was carried out with a Norelco diffractometer equipped w i t h a copper target, scanning speed of 2 ° 2 0 per minute, the scale factor setting at 8 . Scanning occurred over the range either from 2 ° to 35°20 for clay mineral composition or from 2° to 15°20 for statistical analysis. After the samples were run, each diffractogram was examined, every peak was measured and a record of its dspacing and intensity was compiled. For mineral identifi­ cation, d-spacing could be checked in the common mineral d-spacing lists such as Grim (1963) or Griffin (1970). In order to determine the relative proportion of the endmember clay minerals, the semi-quantitative analysis by peak-height ratios was used. The peak height is a function not only of clay amount but also of size, crystallinity and other factors. According to Griffin and Ingram (1955): It is realized that the use of intensities of (0 0 £) lines as a measure of absolute clay mineral abundances is open to many uncertainties; but as all the samples were handled in the same manner and as only ratios of intensities of (00 A) lines in the same pattern were UBed, the results . . . are considered to be significant. The method to measure the peak-height ratio was explained in detail by Griffin (1970). Thus, to make the estimation of clay proportions contained in the Coldwater O Q O O shale, the 10A/7A and 14A/7A peak height ratios were used. o These peaks represent the illite (001) peak of chlorite (10A) and chlorite and kaolinite(7A). (14A), 78 TABLE 5.— X-ray Diffraction Data for Clay Minerals (Different Treatments).* Clay Minerals Natural Mg-Glyc. Illite, mica 10.0A 10. 0A 7. ISA Kaolinite K sat. Heat 100°C K sat. Heat 555°C 10.0A 10.0A 7. ISA 7. ISA — Chlorite 14.5A 14.5A 14.5A 13.0A Vermiculite 14.5A 14.5A 10. OA 10.0A Montmorillonite 13-15A 18A 10.0A 10.0A *Data after Dr. Max Mortland, Department of Crop and Soil Science, Michigan State University. TABLE 6 .— X-ray Diffraction for clay Minerals and Quartz.* Quartz Illite Kaolinite Chlorite Montmorillonite d(A) hkl d(A) hkl d(A) hkl d(A) hkl d(A) hkl 4.26 100 10.0 001 7.15 001 14.2 001 18.0 001 3.34 101 5.0 002 3.56 002 7.1 002 9.0 002 2.46 110 3.33 003 2.38 003 4.71 003 .6.0 003 2.28 102 2.5 004 1.78 004 3.56 004 4.5 004 79 Analytical results.--Some X-ray diffractograms are shown in Figures 17, 18 and 19. They generally display O relatively symmetrical and sharp 10A peaks suggesting fine­ grained and well-crystallized illite. Kaolinite may be confused with chlorite in the X-ray diffractogram, because O both of them have 7.0A reflection. However, chlorite is O clearly identified by (003) reflection at 4.7A and also O O by the (001) reflection 14A which shifted to 13.7A after O heating the sample to 550°C. At 550°C, the 7A peak disappears; thus, the presence of kaolinite is verified. Clay mineral composition of the Coldwater s h a l e .— The Coldwater shale analysed in this study was composed almost entirely of the minerals illite, kaolinite and chlorite, and colloidal-sized quartz, but in widely different proportions. A minor proportion of vermiculite was found in the samples. However, it was diluted by illite and could be detected only by the additional CEC analysis. Montmorillonite and mixed-layer minerals were not detected in the X-ray diffraction studies. study of Lower Mississippian sediments, Asseez In a (1967) also recognized that kaolinite, illite and chlorite are the only clay minerals in his samples. The absence of montmorillonite and mixed-layer clays could be interpreted as meaning that either no such clays were derived from the source areas, or were present but transformed to other minerals during burial. 80 t.M M | 8V *<019 C k » ), t i l l Figure 17.— X-ray Diffractogram— Sample 8A 81 < ’: •r ':•« t: *. ♦i •: M1; * -Ii itfli »i •" *.:•* •■;4;;t:•* «*• i:ii \.ll -« jt ;i ;m i•l♦t ;♦n n; •:i # 515irjrm M liiius p MiMllt flu* Figure 18.— X-ray Diffractogram— Sample 4B N m CKMf)IW 83 Based on the study of the clay mineral composition of the Lower Paleozoic shales of Illinois, Grim and asso­ ciates {1957) found that illite is a prominent component, chlorite and kaolinite are present in lesser amounts, and montmorillonite is usually absent. They suggested that the montmorillonite and kaolinite may have been transformed into illite by the diagnostic process. In the old sediments such as the Coldwater shales, the same process may take place. However, the kaolinite content is relatively high in the Coldwater mineral composition. The conditions to form kaolinite are much different than those to form montmorillonite (Grim, 1958; Keller, 1970; and many others). Therefore, based on the fact that the kaolinite is abundant and the montmorillonite is absent, the writer believes that in the source areas the conditions of climate and topology apparently favored the formation of kaolinite instead of the montmorillonite. If it is true, the Cold- water sediments should come from a region with the abundance of granites and gneisses, the climate should be ' warm, with high rainfall and good drainage. Lateral change in clays and lateral gradationr in lithology.— An attempt was made to determine any significance of vertical and lateral changes within the clay mineral assemblages. As shown in Figure 18 the sample 4B (eastern O O facies) has the 7.07A peak more intense than the 10.04A peak, suggesting that the kaolinite content is relatively 84 abundant compared with the illite. On the other hand,. O sample IOC (Figure 19) of the western facies, has the 7.07A O peak less intense than the 10A peak. The 10A/7A ratio is shown in Table 7 illustrating the variation of the illite content with respect to the kaolinite within the Basin. Chlorite gave a relatively weak (001) reflection, thereO fore some 14/7A cannot be recorded as shown in Table 7. The chlorite content is so low (about 2-4% total clays) that it could be considered insignificant. O O As shown in Figures 20, 21 and 22, the 10A/7A ratio increases from east Michigan toward the west, there­ fore indicating significant change in the proportion of clays from east to west. The statistical analysis (Appendix 1) shows that there is lateral change in clays within the Basin. The lateral change in the clay mineral assemblage appears to relate to the lateral gradation in lithology within the Basin. A high proportion of kaolinite appears to prevail in the eastern facies (high quartz sand content)• There is a progressive decrease in kaolinite and a cor­ responding increase in illite and probably chlorite toward the west. Lithofacies shows coarse sand prevailing to the east and fine mud and carbonate lenses occurring in the west. The relation of facies demonstrates the nearshore- offshore relationship. Many investigators, such as Millot 85 nTr- 7 _• ______ Illite_________ * Kaolinite + Chlorite , Chlorite_______ Kaolinite + chlorite Ratios. Sample 1A IB 1C 2A 2B 2C 3A 3B 3C 4A 4B 4C 5A 5B 5C 6A 6B 6C 7A 7B 7C 8A 8B 8C 9A 9B 9C 10A 10B IOC 11A 11B 11C 10A/7A .61 .53 .86 .57 .50 .87 .60 .58 .86 .35 .44 .82 1.93 2.30 . 1.16 .82 1.23 1.19 .87 .66 14A/7A .09 .10 .10 .10 .08 .13 .09 .12 — .05 .09 — .25 — .09 .08 .14 .11 .10 — .56 .72 1.13 1.30 1.17 1.49 — .09 .13 .15 .25 .27 1.20 .20 1~. 55 1.64 1.78 1.08 1.59 1.76 — .23 .18 .12 .17 .10 86 C O L O W A TE R F O R M A TIO N I lilt* ■R a tio K a o lin !!* + C h lo c lt* • S s m p l* . mulmu ; OHmam / I M BM A I — OOIMAV Q 1C! \ L _ J \ ~ T | Ij j f k 91.11 I "2" ,IC • / — I----------1 / — AIllOAM tv jo m ! 1 POVCOMMON I IALAAWOO I o*coc* |__ r ' I t J I — ivjijtw‘ ML.11 • _ «**HI I r L i IwAJMUMAW I CMIOM •KANCH / I HUSOALiV I UNAVQ Figure 20.— Lower Third of Formation. • 87 COLDWATER FORMATION n n u ______ Kaollnlt* ♦ Chlortt* • Sample 10B OUtlOl / ) 5J y r CM A I «B p * Q N tO N ~ r W A W M S tt (A IO N wasmtinaw VAN U K ST. J O R F H H^OAIi l£NAWu Figure 21.— Middle Third of Formation. , 88 COLDWATER FORMATION K aolln1t*+C htorit* • Sam pi* M — T I / % * a* I J IMtV I I J— ,— WON | y L NGHAM I ( M U '--I -4 T = = T i I *11 /._ . ] i j" «*»•'p > I UVMOnON 1 tS'" 1/ \- I ,f J__ Jl__lc ~ -M Figure 22.— Upper Third of Formation. ' 89 (1940, Grim (1953), Weaver (1961) and many others, have suggested that kaolinite generally is rich in continental and nearshore environments and decreases in abundance relative to illite and chlorite in the marine environment. Griffin and Ingram (1955), basing their work on the clay minerals of the Neuse River estuary along the Atlantic Coast of the United States, found that kaolinite is prev­ alent in the source material and decreases in abundance relative to chlorite and illite in saline waters and con­ cluded that the illite and chlorite are high on content at the lower end of the estuary. It is possible to state that the western waters were "more marine" than eastern waters and that the sandier eastern facies therefore was nearer the source. Likely, the upper third samples having higher kaolinite content than those of the lower third in eastern Michigan suggests probably the shoreline prograded closer to Michigan in upper Coldwater time. As previously cited, the Coldwater shale consists of more quartz sand in the upper part in the eastern facies. It suggests that there is a correspondence between an increase in kaolinite con­ tent and in the quartz sand content, both in turn likely related to the proximity of source. The lateral variation in clay suites seaward may be explained by the differential settling velocities of clays. In mixtures of illite and kaolinite, the settling 90 velocity of illite is faster than that of kaolinite in the case of increased salinity 1953). (Whitehouse and Jeffrey, Probably the slow rate of decomposition in sea water gives time for kaolinite to decompose, as kaolinite is generally unstable in the alkaline environment. Keller (1970) suggested that the kaolinite once transported from fresh water to marine probably starts to dissolve. More­ over, the increase in the proportion of illite westward may be because of the cation exchange of potassium and magnesium into the clay supplied from source areas. believed It is (Grim et a l ., 1949) that the "degraded" illite and chlorite could reconstruct their structure by absorb­ ing potassium and magnesium from sea water. The writer has no intention in this clay mineral study to attempt to clear up the controversial question of "environment of formation versus environment of deposi­ tion." The principle objective in this study was to demonstrate the nature of the lateral clay mineral vari­ ations . ENVIRONMENTAL INTERPRETATION The lithologic characteristic and the distribution of the Coldwater Formation may suggest some conclusions regarding the depositional basin and its environment. Within the basinal environment, some factors such as struc­ ture and sea floor topology also control the conditions of sedimentation. The distribution of sediments reflects the basinal shape of the depositional environment o f the Coldwater. In the Saginaw Bay area, the subsidence w a s faster than the surrounding area which allowed rapid deposition and burial favoring the preservation of red color in the upper part and also the relatively organic-free gray shales. Though sinking w a s rapid in the major depocenter area, it is believed sedimentation rates essentially kept pace with subsidence. An interesting observation by Monnett (1948) was that the red zones in the upper part of the Coldwater and * lower part of the Marshall strata, were missing over the crest of an anticlinal fold in Arenac and Ogemaw Counties. Monnett in indicating the distribution of the redbeds in the Marshall formation recognized that ” . . . the red 91 92 colors are absent near the outcrops of the formation in southern and eastern Michigan and in the areas adjacent to the large anticlines in Shiawassee, Bay and Arenac Counties." He related the disappearance of red color to reducing and leaching conditions and concluded that the areal distribu­ tion of red sediments results from the processes after the formation of anticlinal structures. The writer was restricted in his attempts to verify adequately Monnett's hypothesis because of the lack of sufficient well data in strategic locations relative to the arches. However, c o m ­ paring the data of the cross-section of Monnett against the composite structural axes map (Prouty, 1971, Figure 2) the writer recognizes that the reds are generally absent over the fold axes. The writer suggests an alternate theory that the "highs" (anticlinal folds) apparently were areas of high energy and may have precluded ferric ironbearing clay deposition. This would place a penicon- temporaneous timing on the red bed origin and suggest the anticlinal axes were there at the time of red-bed sedimenta­ tion. The writer observed that western Michigan samples were generally somewhat lighter gray on anticlinal* areas developed, for example, in the older Antrim or Traverse formations; and darker gray in "pockets" suggested by local "thicks" on the isopach map. It is obvious that there exists an oxidizing condition in the "high" areas precluding 93 the preservation of organic m a t t e r , and the sediments are lighter shades (of gray, usually) the "low" areas. than those deposited in However, the well samples were scattered such that no precise pattern of distribution of "darker" and "lighter" Coldwater according to "highs" and "lows" was displayed in this study as Asseez (1967, 1969) considered possible in his studies of the Antrim shale color distribution. The common area in central Michigan where there is no red Coldwater darker in color (Figure 14) and the shale is generally (Figure 13), the crystalline dolomitic zones are highly pyritiferous, further suggesting a local reducing environment. This is probably caused by local deeper water in a lower energy area of relatively restricted circulation. It is of interest to note that the above area is also the approximate position of the Coldwater secondary depocenter, the present structural basin and post-Osagian depocenter. Though the Coldwater and earlier depositional and major structural centers were farther east (Prouty, 1971), this study wo u l d indi­ cate that the structural shift was well in effect by Coldwater time and that at least there existed a secondary basin, at the present center. A useful environmental indicator in this study was the illite/kaolinite + chlorite ratio. This ratio sug­ gests a quantitative estimate of the relative "marine-ness" 94 of a particular locality. As previously cited, kaolinite is prevalent in fluviatile and near**shore sediments, but it is unstable in open marine environment. In general, the lateral variation in kaolinite abundance m a y relate to a trend from non-marine to open ocean depositional environment. The highest ratio could indicate that, relatively, illite is more abundant than kaolinite; there­ fore farther from the shoreline, or "more marine." Samples in the eastern half of Michigan are somewhat low in ratio therefore they are regarded as having been deposited in a very near-shore environment, or "less marine." Lithologic and paleontologic data support the use of illite/kaolinite + chlorite ratio as an indicator of relative "marine-ness" of samples. A study of the environmental implication of fossils was made. Unfortunately, there are few exposures of the Coldwater shale and few fossils available for study. Most fossils collected from well cuttings were fragmented. Miller and Garner (1953, 1955) reported the follow­ ing cephalopoda from the Coldwater exposures in Branch County Michigan: Chouteouoceras ? s p . , Vestinautilus altidorsalis, Gattendorfia ? sp., Munsteroceras pergibbosum, Cycloceras ehlersi, and Mooreoceras. In the well-cuttings from the western part of the Basin, fragments of bryozoans, crinoid stems, brachiopods and few well preserved ostracods were observed, but only 95 the bryozoan fragments were abundant. Schopf (1969) and many others emphasized the relationship of the zoarial growth forms of the bryozoans to the environmental condi­ tions. The thin branching zoaria of the Coldwater may suggest relative deep and quiet water in western Michigan. However/ precise sedimentary environmental interpretations are of restricted value. In the eastern half of Michigan/ Lane (1900) reported some genera from several Coldwater exposures along the eastern lake shore of Huron County/. Michigan: Spirifer, Pleurotomaria, Orthis, Mya l i n a , Crenipectan/ Aviculopecten and Edmondia. Therefore, it is assumed that two communities of pelecypods and spiriferid brachiopods were predominant in the east. All of information may suggest a deltaic origin for the Coldwater shale with the Michigan Coldwater mostly prodeltaic. As a result of recent studies of modern deltas, criteria for the recognition of the deltaic deposits are well understood. Fisk and associates (1954) basing their study on the Mississippi delta proposed that the subaerial delta plain with its marshes, bays, distributaries and the subaqueous delta front and prodelta zones are the--principal depositional environments of a delta. One most notable feature of most modern deltas is the vertical change from massive silty clay of the prodelta zone into interbedded silt, clay and cross-laminated sand in the delta front zone 96 {Shepard, 1960; Allen, 1965). The Coldwater shale grades upward into the Marshall sandstone and their contact is con­ sidered gradational in eastern Michigan. The latter forma­ tion is widespread within Michigan and it forms geo­ metrically a continuous sheet sand. Evidences of cross­ bedding were reported from Marshall exposures in Huron and Sanilac Counties {Lane, 1900; Monnett, 1948). The relation­ ship of the Coldwater shale and the Marshall sandstone could be regarded as the vertical gradation of a prodelta into the delta front. The thick mass of silty shale and shale with more than 20% of sand of the Coldwater formation in the east could be assigned as the prodelta silty clay, and the shale with less than 20% of sand is the prodelta clay; both show the general picture of a prodelta environ­ ment {Figure 23). It is believed that a delta was formed to the east of Michigan, Findlay Arch. in the general region of the Silts and clays were swept westward into the Michigan Basin and deposited in the prodelta zone (Coldwater shale) to build up a platform necessary for the delta advance. The delta growth continued and sand deposited forming a continuous body of sand around the growing delta front (Marshall sandstone). Howevet, despite the progradation of the delta toward Michigan, evidence of its deltaic plain and channel fills is yet to be observed within the state of Michigan. They most likely did not manifest this far west and would not, of course, survive 97 ----L.„--— -----J_____L ! ••t « • ! : I m *i I •I m m m «*++* . NlilBlL • I!:::: SH A L LO W —M A R IN E WATER -1:i "=i:-T ..'-.y ._J. /fV-’iSa LV.:Jiirr';i T;"TT^:ViiH^hyynTnTTi^^ .1---------, _ J 1----------, n Mississippi Dolta Dispositional g2jf^ggmental_^a^o^^iBK^1954^ — i 1| i I j l— Pham CI>anq,l4T3 Figure 23.— Depositional Environment of the Coldwater Formation. 98 the post-Mississippian erosion that has exposed older Paleozoic in the present day area of the Findlay Arch and old Cincinnatia. PALEOGEOGRAPHY The purpose o£ this section is to interpret the origin of the Coldwater formation in Michigan and to test the extent to which this interpretation is harmonic with the adjoining areas in terms of the sedimentary and tectonic frameworks. General Setting During the Late Devonian-Early Mississippian, the Michigan, Appalachian and Illinois Basins were major areas of subsidence; the Laurentian Highlands, Wisconsin High­ lands were apparently low and stable. The Cincinnati Arch separating the Michigan Basin and Appalachian Basin stood as a low peninsula at its maximum extent, perhapB reduced to small swampy islands. The mountainous northern Appalachians which were formed at the close of the Devonian by the Acadian disturbance were eroded intensively supply­ ing clastic terrigenous sediments into the subsidence areas. The epeiric shallow sea covered a large part of the central United States, especially in the Mississippi Valley region. The history of Late Devonian to Early Mississippian involves uplift movement of lands in the mobile belts as well as portions of the craton, and oscillation of 99 100 sea-level. In general, the sedimentary framework consists of predominantly coarse to fine elastics in the areas east of the Cincinnati Arch, and medium to fine elastics and non-clastics west of this arch. Paleogeography During Deposition of the Antrim, Bedford and Berea Formations The paleogeography in Michigan, Ohio and adjacent states during Antrim and Bedford-Berea depositions has been discussed by a number of investigators 1954; Pelletier, (Pepper et a l ., 1958; A s s e e z , 1967, 1969). During the deposition of Antrim shale, land masses were low and provided muds to the epeiric sea. land masses were the Ozark Dome Highlands, Lexington Dome The known (Ozarkia)-, Wisconsin (a portion of the Cincinnati A r c h ) , New Brunswickia and Siouxia. The epeiric sea was widespread over the largest part of east central United States. region The black shale can be observed in the Hudson Bay (Long Rapids Formation), in Michigan Basin (Antrim shale), in Ohio and Pennsylvania (Ohio shale) and Indiana and Illinois (New Albany shale). The sea was somewhat shallow, probably less than 100 feet (LeMone, 1964). Thick mats of floating alga may have caused a reduction in wave and tidal action and contributed organic matter to bring about a strong reducing environment. 101 The Bedford-Berea deposition marked a dominance of clastic sediments which were carried by rivers into the Appalachian, Michigan and Illinois Basins. The Wisconsin Highlands and Canadian Shield were low but the orogenically developing Appalachia underwent activity and erosion. Thick fluviatile sediments of Pocono in Pennsyl­ vania and Maryland region suggested a vast coastal plain in this area (Pelletier, 195B). More fine sands and muds from eastern elevated land masses were carried by swift running streams flowing westward across the Pocono coastal plain into the shallow Ohio Bay. Among them, one river across Pennsylvania formed the Cussewago delta in north­ eastern Ohio. Another river formed the Virginia-Carolina delta in southeast Ohio. These deltas reached a maximum development in Middle Bedford time (Pepper, et a l ., 1954). The Bedford delta was built of sediments derived from the Northern Appalachians and carried southward by the Ontario River into the Ohio Bay (Figure 24). This delta reached its maximum extent in Middle Bedford time. The Cincinnati Arch formed a long peninsula, Cincinnatia, which separated the Michigan and Appalachian Basins (Pepper, et al., 1954). The Ohio Bay was landlocked and likely showed restricted wave and tidal action. In the Michigan Basin, influx of elastics entered from northwestern and northeastern sources. The former possibly built a delta with streams flowing eastward from 102 i . y T' r , i m.m* m . >— . . ■ . j .X LAURENTIAN Sjg a & s & o is a e s is r * * *iK>7nT/ ^ i S M W M m . kfc-wv-pyyiitr mm w m m led ford larea '.<.»'Alf, E lls w o rth P ro d elta Zone mim-i 1 Front to fe is S s i Prodelta ■ % Zone ’$*! .ii-r//».;iv»•rif*§> . •' BR !L M J » i._ m in i & tiiif “ m Berea Ohio Bay Figure 24.— Paleogeography during Bedford Berea Delta Disposition (after Pepper, et a l . , 1954 and Assgez, 1967). X03 the Wisconsin Highlands. (Ellsworth) This mass of green shale in the western half of the Basin may represent a prodelta relating to a delta farther west 1969). (Asseez, 1967# At the same time Ellsworth sediments reached the Basin, in the east the Ontario River built a birdfoot delta of which the Bedford formed the prodelta and the Berea, the deltafront. The shoreline prograded toward Bay and Huron Counties, and a delta plain was in the Lake Huron area. Distributaries advanced toward Michigan Bay and marshes developed. The Sunbury marked the return of a quiet and w i d e ­ spread sea over a large area of Michigan, Ohio, Kentucky, West Virginia and Pennsylvania. The rate of sedimentation by streams into Michigan Bay and Ohio Bay decreased, and the slow deposition of black muds prevailed. Swampy shores were formed where the deltas were inundated. Quiet water and restricted circulation must have prevailed in the epeiric sea. Paleogeography During Deposition of the Coldwater Formation By the early Coldwater deposition, influx of clastic sediments entered the areas of subsidence. Uplift movement occurred in the source areas and streams rejuvenated. More fine elastics passed over the Pocono coastal plains by streams flowing westward, reaching Ohio Bay and Michigan Bay and also over the Cincinnati Arch into the Illinois 104 5 u ! C o ld w a te r 3 sss M ichigan Bay 1 Cuyahoga Ohio Bay / ph a . m Chung t Ufa Figure 25.— Paleoglography during the early stages of the Coldwater Delta. 105 Basin. The Ontario River brought sediments into Michigan and Ohio (Figure 25). Fine silts and muds deposited throughout the epeiric sea— the Coldwater shale in Michigan, the Cuyahoga in Ohio and Pennsylvania, and the New Providence in Illinois and Indiana. The Wisconsin "Highlands” was stable at this time supplying little or no sediments into Michigan. In a study of the dispersal centers of some of the Paleozoic systems, Potter, et a l . (1961) concluded that the Osage and Kinderhook subgraywackes of the Illinois and Michigan Basins were derived from the northern Appalachian area. Another dispersal center to the east, the oro- genically elevated Appalachia, provided vast quantities of clastic sediments to the epeiric shallow sea. The Pocono sediments were apparently fluviatile and were derived from the source located in the vicinity of Atlantic City, New Jersey (Pelletier, 1958). Lithologically, Pocono sedi­ ments composed of thick-bedded conglomerates and quartzitic sandstones. Pelletier (1958) recognized that toward the west the Pocono underwent diminution in numbers of the pebbles and the sand/shale ratio greater than two in eastern Pennsylvania and Maryland decreased to less than one in northwestern Pennsylvania and Ohio. It is clear that most sands from Appalachia deposited in the east and fine silts and clays winnowed and carried westward into the Ohio Bay. Cincinnatia stood as a low peninsula 106 precluding sediments of the Appalachian Basin from entering the Michigan Basin in the earlier Bedford-Berea time. It reduced in size and elevation by the beginning of Coldwater deposition. The writer believes that if any sediments reached the Michigan area from Appalachia, it consisted only of fine silts and muds. Sands and silts found in the upper part of the Coldwater and Marshall formations were carried from the Laurentian Highlands by a river system flowing southwestward and emptying its loads into the Michigan Bay. As previously discussed# in Michigan the Coldwater forms a prodelta (Figure 23). The delta front and the alluvial plain were in the general area of the Findlay Arch (Old Cincinnatia). Near the end of the Coldwater deposition, the uplift movement was stronger in the Laurentian Highlands. Fine sands and silts were carried into the Michigan, Appalachian and Illinois Basins. The shoreline prograded westward and southward away from the Ontario region. to raise and formed a low peninsula Cincinnatia began (Figure 26), but it was probably smaller in extent than it was during the Bedford deposition. The Borden sediments carried southwestward from the Canadian Shield and also formed a delta in Illinois and Indiana but the water was somewhat deeper than in the Michigan and Ohio Bays (Lineback, 1966). 107 In the Mississippi Valley region, shallow and clear water was prevalent. in this area. Thick carbonates deposited 108 15TS51 Coldw ater ftW5N Prodelta Zone Cuyahoga ?;<'i ft.; «>■i1v.» / ■t v* ?>*:« - -' ,V rt-f 1 * - ■V V* Ohio Bay Pocono coastal Plain j^ Figure 26.— Paleogeography during the late stages of the Coldwater Delta and earliest stage of the Marshall unit. CYCLIC SEDIMENTATION OP UPPER DEVONIAN AND LOWER MISSISSIPPIAN ROCKS IN MICHIGAN It is apparent that the Upper Devonian-Lower Mississippian rocks in Michigan demonstrate cyclic sedi­ mentation. This is indicated by two repetitions of lower black shale units followed by gray shales and sandstones. The interpretation of the black shale deposition of the Antrim (first cycle) and Sunbury (second cycle) were trangressive phases in widespread shallow seas cover ing almost the entire Basin, while the adjoining land masses reduced. The gray shale and upper sandstone units such as the Bedford-Berea Marshall (second cycle) (first cycle) and Coldwater- represent regressive phases, resulting when the rivers prograded their deltas filling and reducing the size of the shallow sea. Figure 27 may be helpful in visualizing these relationships. Most of the contacts between formations are gradational. Antrim-Bedford-Berea Sequence * The Antrim-Bedford-Berea relationship was dis­ cussed by LeMone (1964) and Asseez (1967, 1969). The Antrim was divided into two distinct units and the lower 109 110 LITHOLOQY EUSTATIC +P- Marshall Si. C o ld w t t t r Sh. S u n b u ry Sh B e d fo rd Sh A n trim Sh. Figure 27.— Trangressive-Regressive "Cycles" of the Late Devonian and Early Mississippian in Michigan. Ill unit can be correlated throughout the Basin. The green shale lithosome, Ellsworth, in the west, is gradational and interfingering with the upper Antrim unit. The Antrim- Bedford-Berea sequence represents a suite of lithotopes ranging shoreward from shallow marine to the prodelta sandstone) (Bedford shale) and the delta front (Berea (Asseez, 1967, 1969). regressive overlap (offlap). (Antrim black shale) The sequence forms the The trangressive Antrim developed when the rate of subsidence exceeded that of deposition and marine black shale spread almost entirely over the Basin and adjacent states. During the regressive Bedford-Berea period, the rate of deposition exceeded the rate of subsidence and westward progradation of the shore­ line resulted. Figures 28 and 29 show restored sections of cycles 1 and 2. Time lines are believed to cut the isoliths in a theoretical manner such that the prodelta and delta front beds become younger eastward. The extent of the time transcension is not discernable in any quantitative manner and is displayed in a diagrammatic manner only. Sunbury-Coldwater-Marshall Sequence The Sunbury-Coldwater-Marshall interval also repre­ sents a trangressive cycle, in the early Mississippian in Michigan. The Coldwater formation marked clastic deposi­ tion replacing the reducing marine conditions during WEST Sunbury Not to scale Figure 28.— Antrim-Bedford-Berea-Cycle 1 (modified from Asseez, 1967) WEST 113 Tim e line Sunbury Not to scale Figure 29.— Sunbury-Coldwater-Marshall-Cycle 2. 114 Sunbury deposition. The Coldwater shale is referred to a pro-delta sub-environment of a complex deltaic system which has been eroded away directly east of Michigan in the general area of the Findlay Arch (Old Cincinnatia). The Marshall formation is a sand sheet and it is question­ able that it would be described accurately in the geomorphic sense as in the Berea sandstone. However, the Sunbury- Coldwater-Marshall sequence in Michigan proper is largely marine, as opposed to the Bedford and Berea of the earlier sequence, and apparently represent a neritic phase tied in likely with faster basinal settling at that time. A favor­ able analogy of this sequence appears favorable in the Catskill alluvial plane which spread westward across New York and Pennsylvania during Middle to Late Devonian deposition. Considering the Portage-Chemung-Montrose (Catskill) lithotopes (which might fit loosely into the "parvafacieB" concept of Caster, 1934) the Sunbury and western Coldwater facies of Michigan might find a counter­ part in the Portage dark to gray muds; and the eastern Coldwater facies and the regionally distributed and the regionally distributed Marshall to the marine Chemung. The delta plain portion of the Coldwater and Marshall, conceived as occurring generally east of Michigan in the area of the Findlay Arch and Cincinnatia source prior to post-Mississippian erosion, would represent the non-marine Montrose (Catskill) portion. 115 In a deltaic progradation situation, the sequence is progressively younger in the basinward direction. It is suggested here that a part of the lower Coldwater is equivalent to a part of the Sunbury black shale. Also, at the time the Marshall sediments deposited in the far east, some of upper Coldwater muds still were being deposited basinward. The Bedford and Berea of the older cycle are restricted to the eastern half of the Basin because of the presence of a north-south "barrier" of some kind in central southern Michigan. On the contrary, the Sunbury-Coldwater- Marshall cycle is distributed throughout the Basin because the barrier is no longer present. In a study of late Mississippian rythmic sedimen­ tation of the Mississippi Valley, Swann (1964) observed many alternations of limestone and sandstone units of the Chesterian series, which were deposited in alternating marine environments and deltas of the so-called "Michigan River" flowing from the northeast into a sea in southern Illinois. Swann considered that neither sea level fluctua­ tions nor the pulses of tectonism in the source areas caused the cyclic sedimentation. He concluded that varia- tions in rainfall controlled the rythmic sedimentation and that each major rainy period marked a major delta. In the case of trangressive-regressive cycles of early Mississippian in the Michigan Basin, the writer believes 116 that episodes of epeirogenic warping alternating with the subsidence of the Basin appear more logical as an explana­ tion. At time of quiescence, a slow transgression of the shallow sea over the Basin including a prevalent reducing environment would result in widespread deposition of black muds in the Basin. At time of uplift activity in the source a r e a s , great volumes of terrigenous sediments would be accumulated in the Basin reducing the size of the shallow sea. The progradation of the Bedford-Berea birdfoot delta may be tied synorogenically to the Acadian Orogeny. The regressive phase at the beginning of the Coldwater time •*» ended the black shale sequence in Michigan. the Coldwater isopach and structure maps The study of (Figures 3 and 4) reveal that the Michigan Basin was starting to accumulate sediments at that time. Marshall formation The irregular isopach of the (LeMone, 1964) and the shift of pre- Meramecan depocenters from Saginaw Bay area toward the present center (Prouty, 1971) infer the tectonic effects of the Appalachian Orogeny. Throughout the Late Devonian-Early Mississipean the Laurentian and the Wisconsin Highlands were unstable. The uplift movement apparently occurred synorogenically with the Acadian orogeny and the Appalachian disturbance. The Michigan Basin started to fill with sediments at the beginning of the Coldwater deposition, then underwent 117 further changes during the deposition of the Marshall sand­ stone up to at least Middle Mississippian (Meraxnecan) time. The delta building in early Mississippian in the Basin apparently was a prelude to the alternating alluvial plain marine conditions in the Michigan Basin in Pennsyl­ vanian time. Time-Stratigraphic Correlations As pointed out earlier, the time lines in Figures 28 and 29 are hypothetical. Time-stratigraphic correla­ tion of Early Mississippian in Michigan is not well under­ stood. Oden (1952) in his study on the occurrence of Mississippian brachiopods in Michigan concluded that timestratigraphy cannot be determined by using brachiopods of the Coldwater and Marshall formations. Moreover, scattered outcrops in Michigan also add more difficulties to the time-stratigraphic problems. It is possible that a palynological study of the Coldwater formation and potential equivalent formations in the bordering states may shed additional light regard­ ing synchronous correlations. Eames One such study by Leonard (Michigan State University) on the Cuy^Jioga forma­ tion in Ohio is nearing completion. CONCLUSIONS Some significant conclusions derived from this study are as follows: 1. The regional structural contour map constructed on the base of the Coldwater Formation shows that the Michigan Basin has two structural centers. The Coldwater depositional and major structural centers located in the Saginaw Bay area do not coincide to the present deepest part of the Basin. the opinion This fact appears to be in keeping with {Prouty, 1971) that the Pre-Meramecan depo- centers centering in eastern Michigan near Saginaw Bay area shifted west to the present position in central southern Michigan. This study reveals that the structural shift is well in effect by Coldwater time and a secondary basin exists at the present center. 2. The eastward thickening of the Coldwater Forma­ tion infers the proximity of the eastern source. 3. Lithologically, the Coldwater formation shows that the elastics are coarsest in the eastern area and become progressively finer to the west. Two facies are recognized and the facies change in continuous. 4. About a maximum of 40 percent of quartz sand is determined from sandy units in the east. 118 The sand 119 percentage decreases westward and the limit of sand deposi­ tion is located in the central part of the Basin. 5. The highest proportion of carbonate deposits are in the western counties of Michigan. 6. In general, the lithofacies isoliths are parallel to the isopach l i n e s . 7. The western facies is characterized by an abundance of clay-ironstone concretions. Concretion zones are concentrated in the upper part of the Coldwater Forma­ tion in the west. 8. The Coldwater sediments are mostly marine. Although no data are available on the regional distribution of grain sizes, this study reveals a strong relationship between the coarser elastics and the kaolinite content, with markedly higher proportion of kaolinite relative to illite in coarser sediments. 9. Lightly oxidizing conditions persist through­ out the Coldwater environment partially based on the light gray sediments with the exception of an area in central Michigan where a light reducing condition existed. Dark gray and highly pyritiferous sediments are observed in this area indicating a possible deep, or at least par•* tially restricted, environment. 10. Although no precise interpretation of depth can be made, the sea in the nearshore, eastern Michigan 120 area was shallower and less saline than in the offshore western Michigan region. 11. The clay mineral suite of Coldwater shale consists of kaolinite, illite and chlorite. No mont- morillonite was recorded. 12. An abundance of kaolinite proportion in the Coldwater shale may reasonably indicate that the Coldwater sediments came from a granitic and/or gneissic source area where high rainfall and warm climate were indicated. Pub­ lished data on Pocono sediments (considered pre-Chesterian Mississippian) in western Pennsylvania, indicate a shaley facies of the eastern Pennsylvania sandstones. This fact strengthens the conclusion that the quartz sandy Coldwater of eastern Michigan is more closely related to a nearby source (Cincinnatia). 13. A paleogeographic map constructed for the period during Coldwater deposition depicts a low peninsula, Cincinnatia, in the Findlay Arch area. 14. This study suggests a deltaic system developed east of Michigan. Coldwater shale is considered a prodelta shale whose delta front and alluvial plain probably are located in the general area of the Findlay Arch. * 15. Two trangressive-regressive "cycles" of Late Devonian and Early Mississippian age in Michigan are recognized by the repetitions of black shale units. 121 (trangressive phase) followed by coarser clastic units (regressive phase). The Sunbury-Coldwater-Marshall cycle is distributed throughout most of southern Michigan whereas the upper part (Bedford-Berea) of the older Antrim-Bedford- Berea cycle cuts out along a north-south "barrier" of some kind in central Michigan. 16. The deposition of the Coldwater shale is a prelude to active evolutionary changes in the Michigan Basin during the Marshall and up to at least Middle Mississippian (Meramecan) time. BIBLIOGRAPHY 122 BIBLIOGRAPHY Allen, r. R. L. 1965. Late Quaternary Niger Delta and adjacent areas: Sedimentary environments and lithofacies. Am. Assoc. Petroleum Geologists Bull., 49:547-600. Asseez, L. O. 1967. Stratigraphy and Paleogeography of Lower Mississippian sediments of the Michigan Basin. Ph.D. Thesis, Michigan State University. 1969. Paleogeography of Lower Mississippian rocks of Michigan Basin. Amer. Assoc. Petroleum Geologists Bull., 53:127-135. Barrell J. 1912. Criteria for the recognition of ancient delta deposits. Geol. Soc. America Bull., 23:377-446. B a t e s , i!. C. 1953. Rational theory of delta formation. Am. Assoc. Petroleum Geologists Bull, 37:2119-2162. Bishop, M. S. 1940. Isopachous studies of Ellsworth to Traverse limestone sections of southwestern Michigan. Am. Assoc. Petroleum Geologists Bull, 24:2150-2162. Bloomer A. T. 1969. A regional study of the Middle Devonian Dundee dolomite in the Michigan Basin. M.S. Thesis, Michigan State University. Bolger, R. C., and Prouty, C. E. 1953. Upper Devonian and Mississippian stratigraphy of Cameron County, Pennsylvania. Penn. Acad. Sci. Proc, 27. B r o w n , . E. 1955. Physical limits of glauconite formation. Am. Assoc. Petroleum Geologists Bull., 39:484-492. C o h e e , >. V., and Underwood, L. B. 1945. Sections and thicknesses of Dundee and Rogers City limestone in the Michigan Basin. U.S. Geol. Survey, Oil and Gas Inv., P.M. 38. et a l . 1951. Thickness and Lithology of Upper Devonian and Carboniferous Rocks in Michigan. U.S. Geol. Survey, Oil and Gas Inv., P.M. 38. Ells, G 1969. Architecture of the Michigan Basin. Michigan Basin Geological Society, guidebook annual field excursion. Fisk, H N., et a l . 1954. Sedimentary framework of the modern Mississippi delta. Jour. Sed. Petrology, 24:76-99. G o r d o n , C. H. 1900. Geological Report on Sanilac County, Michigan. Geol. Survey of Michigan, 7(3)1-34. G r e e n , >. A. 1957. Trenton Structure in Ohio, Indiana and Northern Illinois. Am. Assoc. Petroleum Geologists Bull., 41:627-642. Griffin G. M. 1964. Development of clay mineral zones during deltaic migration. Am. Assoc. Petroleum Geologists Bull., 48:57-69. 1971. Interpretation of X-ray diffraction data, pp. 521-569. In: Procedures in Sedimentary Petrology, ed. by Robert E * Ca r v e r . New York: John Wiley and Sons, Inc. and Ingram, R. L. 1955. Clay minerals of the Neuse River Estuary. Jour. Sed. Petrology, 25:194-200. Grim, R E. 1951. Depositional environments of red and green shales. Jour. Sed. Petrology, 21:226-232. 1958. Concept of diagenesis in argillaceous sediments. Am. Assoc. Petroleum Geologists Bull., 42:246-253. 125 ________. 1968. Clay Mineralogy (2nd ed.). McGraw-Hill Book C o . , 596 p. New York: ________, Bradley, W. F . , and White, W. A. 1957. Petrology of the Paleozoic shales of Illinois. Illinois State Geol. S u r v . , Rept. Invest, 203, 35 p. Hale, L. 19 41. Study of Sediments and Stratigraphy of the Lower Mississippian in Western Michigan. Am. Assoc. Petroleum Geologists Bull., 25:713-723. Hicks, L. E. 1878. The Waverly group in central Ohio. Am. Jour. Sci., 3rd s e r . , 16:216-224. Hinze, W. J. 1963. Regional gravity and magnetic anomaly maps of the Southern P. Michigan. R.I. No. 1, Michigan Geol. Survey. Holden, F. T. 1942. Lower and Middle Mississippian Atratigraphy of Ohio. Jour. Geology, 50:67. Hyde, J. E. 1921. Geology of Camp Sherman quadrangle. Ohio Geol. Surv., 4th ser., Bull. 23. Jodry, R. L. 1957. Reflection of possible deep structures b y Traverse Group facies changes in Western Michigan. Am. Assoc. Petroleum Geologists Bull., 41:2677-2694. Kay, M. 1942. Development of the northern Allegheny synclinorium and adjoining regions. Geol. Soc. America Bull., 53:1601-1658. ________. 1951. North American geosynclines. America Memoir 48. Geol. Soc. Keller, W. D. 1956. Clay minerals and environments. Am. Assoc. Petroleum Geologist Bull., 40:2689-2710. . 1970. Environmental aspects of clay minerals. Jour. Sed. Petrology, 40:788-854. Kilbourne, D. E. 1947. Origin and development of the Howell anticline. Unpublished M.S.*Thesis, Michigan State University. Krumbein, W. C . , and Garrels, R. M. 1952. Origin and classification of chemical sediments in terms of pH and oxidation-reduction potentials. Jour. Geology, 60:1-33. 126 Krumbein, W. C . , and Sloss, L. L. 1963. Stratigraphy and Sedimentation (2nd e d . ). San Franc isco: Freeman. Krynine, P. D. 1957. The megascopic study and field classification of sedimentary rocks. Tech. Paper 130, Pennsylvania State University. Lane, A. C. 1893. 1892. Michigan Geol. Survey Kept. 1891 and _______ . 1900. Geological Report o n Huron County. Geol. Survey of Michigan, 7(2)1-329. LeMone, D. V. The Upper Devonian and Lower Mississippian sediments of the Michigan Basin and Bay County, Michigan. Unpublished Ph.D. Thesis, Michigan State University. Lineback, J. A. 1966. Deep-water sediments adjacent to the Borden siltstone (Mississippian) delta in southern Illinois. Illinois State Geol. Survey Circ. 401, 48 p. Lockett, J. R. 1947. Development of the structures in Basin areas of northern United States. Am. Assoc. Petroleum Geologists Bull., 31:429-446. Martin, Helen M. 1957. Outline of the geologic history of Hillsdale County. Michigan Dept. Conservation, Geol. Survey D i v . , 11 p. _______ . 1958. County. D i v . , 11 Outline of the geologic history of Branch Michigan Dept. Conservation, Geol. Survey p. McGregor, D. J. Stratigraphic analysis of Upper Devonian and Mississippian rocks in Michigan Basin. Am. Assoc. Petroleum Geologists Bull., 38:2324-2356. Miller, A. K . , and Garner, H. F. 1953. Lower Mississippian Cephalopoda of Michigan, Pt. II, Coiled Nautiloids. Contr. Michigan University Mus. Paleo., 11:111-151. _______ . 1955. Lower Mississippian Cephalbpods of Michigan, Pt. Ill, Ammonoids and Summary. Contr. Michigan University Mus. Paleo., 12:113-173. Monnett, V. B. 1948. Mississippian Marshall formation of Michigan. Am. Assoc. Petroleum Geologists Bull., 32:629-688. 127 Moser, P. 1963. The Michigan Formation. A study in the use of a computer oriented system in stratigraphic analysis. Ph.D. Thesis, University of Michigan. Newberry, J. S. 1870. Report on the progress of the Geological Survey of Ohio in 1869. Ohio Geol. Survey, Rept. Prog. 1869, Pt. 1, pp. 3-53. Newcombe, R. J. B. 1938. Oil and Gas fields of Michigan. Mich. Geol. Survey Div., Publ. 38, Geol. Ser. 32. Oden, A. L. 1952. The occurrence of Mississippian Brachiopods in Michigan. M.S. Thesis, Michigan State University. Parham, W. E. 1966. Lateral variations of clay mineral assemblages in modern and ancient sediments. Proceedings of the International Clay Conference (ed. by L. Heller and A. W e i s s ) . Jerusalem, Israel, 1:135-145. Pelletier, B. R. 1958. Pocono paleocurrents in Pennsyl­ vania and Maryland. Geol. Soc. American Bull., 69:1033-1064. Pepper, J. F . , DeWitt, W . , Jr., and Demarest, D. F. 1954. Geology of the Bedford Shale and Berea Sandstone in the Appalachian Basin. U.S. Geol. Survey, Prof. Paper 259, 111 p. Pirtle, G. W. 19 32. Michigan Structural Basin and its relationship to surrounding areas. Am. Assoc. Petroleum Geologists Bull., 16:145-152. Potter, B. E . , and Pryor, W. A. 1961. Disposal centers of Paleozoic and later elastics of the upper Mississippi Valley and adjacent areas. Geol. Soc. American Bull., 72:1195-1250. Prosser, C. S. 1912. Ohio Geol. Survey Bull. 15. - Prouty, C. E. 1970. Some Lower Paleozoic sedimentary environments and related paleo-struptural develop­ ment— Michigan Basin area. Abstract of Programs, Geol. Soc. Amer., 2:402. . 1971. Michigan Basin development and the Appalachian Foreland. Submitted to XXIV Inter­ national Geological Congress, Montreal, Ontario, Canada. 128 Sawtelle, E. R . , Jr. 1958. The origin of the Berea sandstone in the Michigan Basin. M.S. Th e s i s , Michigan State University. Scruton, P. 1960. In: Recent 1951-1958. Geologists, Delta building and the deltaic sequence. Sediments, Northwest Gulf of Mexico, Tulsa, Okla.: Am. Assoc. Petroleum pp. 83-101. Schopf, T. J. M. 1969. Paleoecology of Ectoprocts (Bryozoans). Jour. Paleontology, 43:234-244. Stocdale, P. B. 19 39. Lower Mississippian Rocks of the East Central Interior. Geol. Soc. America, Special Paper 22. Swann, D. H. 1964. Late Mississippian rhythmic sediments of Mississippi Valley. Am. Assoc. Petroleum Geologists Bull., 48:637-658. Szmuc, E. J. 1957. Stratigraphy and Paleontology of the Cuyahoga Formation of northern Ohio. Ph.D. Thesis, Ohio State University. Tarbell, E. 1941. Antrim-Ellsworth-Coldwater Shales Formations in Michigan. Am. Assoc. Petroleum Geologists Bull., 25:724-733. Ver Steeg, K. 194 7. Black Hand Sandstone and conglomerate in Ohio. Geol. Soc. American Bull., 58:703-728. Walker, T. R. 1967. Formation of red beds in modern and ancient deserts. Geol. Soc. America Bull., 78:353-368. Weaver, C. E, 1958. Geologic interpretation of argillaceous sediments. Am. Assoc. Petroleum Geologists Bull., 42:251-271. Weller, J. M . , et a l . 1948. Mississippian Formations of North America. Geol. Soc. America Bull., 59:91-188. . 1960. Stratigraphic Principles and Practice. New York: Harper and Bros. White, I. C. 1880. The geology of Mercer County. Pennsylvania 2d Geol. Survey Rept. QQQ. _ . 1881. The geology of Erie and Crawford Counties. Pennsylvania 2d Geol. Survey Rept. QQQQ. 129 Whitehouse, U. G., and Jeffrey, L. M. 1953. Chemistry of marine sedimentation. A and M College of Texas, Department of Oceanography. Winchell, A. 1861. Observations on the Geology, Zoology and Botany of the Lower Peninsula. First Bienn. Rept. Progress of Geol. Survey Michigan, 1860. . 1865. Description of New Species from the Marshall Group and Its Equivalents. First Bienn. Rept. Progress of Geol. Survey Michigan, 1860, pp. 109-133. . 1869. On the Geological Age and Equivalents of the Marshall Group. Proc. Phila. Philos. Soc., 11:57-83. Wooten, M. J. 1951. The Coldwater formation in the area of the type locality. M.S. Thesis, Dept, of Geology, Wayne State University. APPENDICES 130 APPENDIX I 131 APPENDIX I STATISTICAL ANALYSIS The following data is the illite/kaolinite + chlorite ratio of eastern and western clay suite. East* ■61, .53# •86f *57? .50? *87? .60? .44? .82? .87? .66? .56. .58? .86? •35, West: 1.93? 2.30, 1.16, .82? 1.23? 1.19, .72, 1.13? 1.30, 1.17, 1.49, 1.20, 1.55? 1.64? 1.78? 1.08, 1.59 ? 1.76. Null Hypothesis: Two samples are random samples from the same population. n^ =*15 n 2 =* 18 Y 1 = .645 y 2 o 1.39 n. 2 E (y< - y 0)2 - 2 .75 i=l 805 -765 -640 -567 -602 -926 -826 -781 -940 -789 GEN 168 169 170 171 172 173 174 175 176 7275 23948 24028 1943 20140 11914 9669 10916 10482 N06 N06 N06 N07 N07 N09 N09 N09 N09 EOS E07 E06 E06 EOS E05 E07 E08 E08 13 29 12 31 09 10 11 06 25 1007 -571 -430 -400 -643 -831 -1000 -800 -640 -727 GLA 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 15084 3912 4762 4101 4985 15451 4143 3565 4957 4885 7986 4665 5352 5740 4812 3898 4237 7234 14500 14665 16558 N17 N17 N17 N17 N17 N17 N17 N18 N18 N18 N18 N19 N19 N19 N19 N19 N20 N20 N20 N20 N20 E01 E01 E02 W01 W01 WO 2 WO 2 E01 W01 W01 WO 2 E01 E03 W01 WO 2 WO 2 E01 E02 W01 W01 WO 2 02 09 20 10 32 06 23 33 09 23 11 11 29 23 09 25 22 07 08 34 31 1030 1040 1045 1030 1017 990 1015 1053 1020 1025 1010 1050 1030 . 1035 1010 1040 1076 1067 1041 1015 1006 1023 953 960 Structure -1400 -1465 -1320 -1480 -1773 -1822 -1781 -1434 -1522 -1400 -1630 -1300 -1212 -1520 -1618 -1680 -1330 -1200 -1490 -1400 -1512 146 Number NmbM GRATIOT 198 199 200 211 212 213 214 215 216 *217 218 219 220 221 222 222 223 224 225 11562 12110 11991 2661 21296 1774 2920 4707 12041 - 9625 2971 12845 18673 2693 2693 16664 2576 16022 12664 HILLDALE 226 227 228 229 230 231 232 233 234 235 236 237 • • 238 239 240 241 242 HURON 243 244 245 246 247 248 Location N09 N09 N09 N09 N09 N10 N10 N10 N10 Nil Nil Nil Nil N12 N12 N12 N12 N12 N12 Thickness Structure W01 W01 W03 W04 W04 W01 W02 WO3 WO4 W01 WO2 WO3 WO4 W01 W01 WOl W02 WO4 W04 05 31 13 10 18 32 19 26 22 34 17 31 11 13 13 31 10 06 21 963 983 1035 1030 1055 975 1015 1015 1041 995 988 1020 1007 1010 1010 1000 1000 1034 1040 -1395 -1320 -1400 -1500 -1459 -1400 -1437 -1482 -1530 -1500 -1470 -1520 -1570 -1580 -1580 -1560 -1666 -1750 -1660 17936 22749 25271 26715 21216 23894 21109 24250 23590 26578 23058 18056 18519 23670 22298 27045 14088 SOS WOl SOS-WOl SOS W02 S05 W02 S05 W O 3 S05 W04 S06 WOl S06 WO2 S06 WO2 S06 W04 S07 WOl S07 WO2 S07 W03 S07 WO4 S08 W02 S08 W04 S09 W O 3 09 35 27 30 02 04 18 04 22 08 35 16 03 28 04 32 04 938 935 -80 -5 -9 +25 -67 -107 +31 0 +59 +60 +246 +114 +150 +163 +215 +280 +300 15420 12508 16222 4593 24002 9224 N15 N15 N15 N15 N15 N15 20 07 27 15 35 14 WO9 W10 W10 Wll E12 E14 945 940 932 1102 1067 -870 -724 -700 -736 -612 0 147 « aPw Number Number 249 250 251 252 253 254 255 256 257 258 259 11738 12907 24789 5519 5045 2180 24040 4509 11834 18019 8107 N15 N15 N16 N16 N16 N17 N17 N17 N17 N18 N18 E16 E10 E12 E13 E15 E10 E10 E14 E15 E12 E13 31 02 36 27 10 28 36 01 22 12 17 INGHAM 260 261 262 263 264 265 266 267 268 22607 9477 4918 4837 24518 10011 22676 8132 3352 NOl N02 N02 N02 N02 N03 N03 N04 N04 E02 E01 WOl WOl W02 E01 WOl E01 WOl 13 01 23 28 16 14 33 15 09 1057 1060 1071 1060 IONIA 269 270 271 272 273 274 275 276 277 278 279 280 10865 25688 15063 5993 3154 25025 27397 20289 11027 15607 11588 3135 N05 N05 N05 N06 N06 N06 N07 N07 N07 N08 N08 N08 WO6 WO6 WO8 W05 W07 W08 WO5 W06 W07 WO5 W07 WO8 04 17 29 05 12 04 08 03 06 10 01 29 1035 1007 1018 1042 12531 23084 23060 10420 17812 15686 12163 8557 17142 N20 N21 N21 N21 N22 N22 N22 N23 N24 E05 E05 EOS E06 EOS E06 E08 EOS E09 04 11 27 16 02 23 01 . 15 10 Z er? Lt Location Thickness 918 1040 1070 1052 1043 1098 1035 1010 1087 965 Structure +423 -830 -531 -376 0 -935 -831 0 +94 -377 -264 -220 -900 -900 -875 -880 -1000 -973 -1068 -1130 -1100 -1027 -860 -1222 -1200 -1040 -1351 -1317 -1200 -1400 -1345 -1120 :osco COUNTY 281 282 283 284 285 286 287 288 289 1283 1250 1222 1300 1270 962 1259 -856 -907 -1029 -1012 -930 -1015 -558 -979 -177 148 Number Number Location Thickness ISABELLA 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 18344 8751 10963 5576 7865 18999 14147 1804 4540 16745 8835 3451 15009 11145 12374 11858 7287 18645 11216 19265 N13 N13 N13 N13 N13 N13 N13 N14 N14 N14 N15 N15 N15 N15 N15 N15 N16 N16 N16 N16 W03 W03 W04 W05 W05 W06 WO6 WO3 WO4 W06 WO3 WO3 W04 W05 W06 W06 WO4 WO4 WO6 WO6 04 20 27 08 22 05 30 01 25 10 04 30 18 21 05 29 20 30 29 35 1013 1016 1000 944 985 923 988 995 998 860 995 974 946 934 847 843 975 896 846 873 -1845 -1770 -1750 -1653 -1654 -1615 -1547 -1684 -1848 -1643 -1750 -1739 -1800 -1736 -1580 -5173 -1700 -1750 -1530 -1623 JACKSON 310 311 312 313 314 315 316 317 318 319 320 321 322 7149 21842 9781 26981 26548 21161 21898 18265 22422 22107 22017 18202 22013 SOI SOI SOI S02 S02 S02 S03 S03 S03 S03 S04 S04 S04 WOl WO3 WO3 WOl WO2 WO3 E01 E02 WOl W03 E02 W02 W03 26 11 34 17 16 29 26 22 28 14 09 24 17 1032 1021 1020 1020 1010 979 -600 -632 -541 -500 -500 -400 -307 -326 -332 -310 -244 -160 -170 KALAMAZOO 323 324 325 326 327 328 329 330 20572 7313 8433 20072 7180 8766 13483 95259 SOI SOI SOI SOI S02 S02 S02 S03 W10 Wll W12 W12 WO 9 W12 W12 Wll 27 13 02 30 21 03 30 13 937 975 960 960 Structure -100 -187 -40 +35 -73 +45 +80 +100 149 Location Thickness 331 332 333 334 6899 7186 25006 17004 S03 S04 S04 S04 Wll W10 Wll W12 31 06 27 19 A LK 335 336 337 338 339 340 341 342 343 344 345 13895 18664 31650 14659 15638 871 17328 20110 20133 16632 27287 N25 N25 N25 N25 N26 N26 N26 N27 N27 N27 N27 W05 W06 W07 WO8 W05 W05 WO8 W05 WO6 W07 WO8 12 16 35 27 06 16 33 26 10 02 17 7103 15568 733 11805 4989 13046 11969 9786 154 6375 16665 6768 18083 13926 18874 6070 11422 13104 12301 14731 18454 9776 18113 17388 17096 15618 N05 N05 N05 N05 NOS N05 N06 N06 N06 N06 N06 N07 N07 N07 N07 No7 N08 N08 N08 N08 N08 N09 N09 N09 N09 N10 WO9 W10 W10 Wll W12 W12 WO9 W10 Wll W12 W12 W09 W10 Wll W12 W12 WO9 W10 W10 Wll W12 W10 Wll W12 W12 W09 23 17 36 08 14 32 19 23 19 04 35 06 13 23 05 32 22 05 16 34 06 14 24 03 16 05 ENT 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 Structure +180 +134 +230 +294 992 903 872 785 960 800 715 885 826 910 783 782 965 877 780 740 782 900 850 814 719 743 885 848 847 782 770 910 820 740 700 860 -343 -614 -700 -435 -146 -200 -275 -170 -13 +100 +41 -755 -535 -630 -480 -400 -300 -833 -716 -576 -486 -447 -910 -895 -728 -577 -476 -1028 -900 -900 -790 -630 -1055 -840 -800 -740 -1224 150 Permit Number Location 372 373 374 15918 16710 16835 LAKE 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 Map Numb Thickness Structure N10 W09 18 N10 Wll 09 N10 Wll 29 901 777 774 -1183 -900 -874 16610 13941 2883 12885 13403 17893 25972 10798 25983 13587 27806 22693 20224 20234 26832 17677 15419 N17 N17 N17 N18 N18 N18 N18 N18 N19 N19 N19 N20 N20 N20 N20 N20 N20 Wll W12 W13 Wll W12 W12 W14 W14 W12 W12 W13 Wll W12 W12 W13 W14 W14 15 22 33 02 13 20 17 24 14 36 20 24 12 30 32 07 12 641 596 597 582 534 590 581 565 571 548 570 635 600 558 533 519 528 -1086 -951 -748 -957 -838 -844 -478 -568 -676 -748 -520 -929 -676 -541 -481 -156 -215 LAPE 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 3307 12933 24048 24010 18530 2402 24075 23947 26696 11286 2562 19736 11777 24142 5069 24233 10466 N06 N06 N06 N06 N07 N07 N07 N07 N07 N08 N08 N09 N09 N09 N09 N10 N10 E09 Ell E12 E12 E09 E09 Ell E12 E12 E09 E09 E09 E10 Ell E12 E10 E12 30 25 06 17 04 36 14 15 25 08 13 15 20 21 26 28 27 LENA 409 410 411 27785 18835 18914 S05 E01 18 S05 E02 05 S05 E03 01 997 1035 1027 1056 1018 1027 -221 -32 -109 -42 -533 -400 -240 -159 -81 -619 -600 -590 -583 -485 -317 -577 -460 -50 -73 -70 151 Location Number 412 413 414 415 416 417 418 419 420 Thickness Structure 23838 23723 26853 23087 23276 21916 24595 23618 16693 S06 S07 S07 S07 S08 S08 S08 S08 S08 E01 E01 E02 E03 E01 E01 E02 E03 E04 20 34 13 25 03 27 15 27 18 +124 +329 +300 +422 +344 +400 +421 +523 +557 LIVINGSTON 421 422 423 424 425 426 427 428 429 430 431 432 433 23073 15875 10038 13518 25868 23374 10990 12481 27030 24029 15263 22995 23426 NOl NOl N02 N02 N02 N03 N03 N03 N03 N03 N04 N04 N04 E04 E06 E03 E04 E04 E03 E03 E04 E05 E06 E03 E06 E06 23 06 09 01 14 02 11 14 25 22 06 20 22 -279 +738 MASON 434 435 436 437 438 439 440 441 442 443 444 445 446 8263 13646 24262 26172 19204 20908 21278 15417 27310 24188 16753 24454 9511 N17 N17 N17 N17 N17 N17 N17 N17 N18 N18 N18 N19 N20 W15 W15 W16 W16 W16 W17 W17 W18 W16 W17 W18 W16 W15 09 22 18 26 36 10 26 26 33 14 03 20 22 MECOSTA 447 448 449 450 451 19603 19628 20240 26503 2613 N13 N13 N13 N13 N13 WO8 WO8 WO9 W10 W10 02 21 01 06 22 -259 1000 510 565 527 888 931 861 759 824 +705 -464 +600 -420 +700 +416 +323 +100 +185 +35 -340 -375 -145 -180 -213 -125 -146 -72 -200 -98 +42 -105 -134 -1478 -1441 -1422 -1164 -1200 152 Map Numb Numbed Location 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 19610 11756 24275 11832 17912 9608 17892 12915 19965 16651 7483 16329 10903 16406 10612 11724 16764 N14 N14 N14 N14 N14 N15 N15 N15 N15 N15 N15 N16 N16 N16 N16 N16 N16 WO 7 WO 8 WO 8 *09 W10 WO 7 WO 8 WO 8 WO 9 W10 W10 WO 7 WO 8 WO 8 WO 9 W10 W10 MIDL 469 470 471 472 473 474 474 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 1738 2267 95135 95128 7524 1694 1360 1142 1435 10969 5430 3664 18085 23861 7357 7726 8870 27768 11584 7767 9960 17806 11675 10095 10847 12388 16271 16347 N13 N13 N13 N13 N13 N13 N14 N14 N14 N14 N14 N14 N16 N21 N21 N21 N22 N22 N22 N22 N23 N23 N23 N23 N23 N23 N24 N24 E01 E01 E02 E02 WOl WOl WOl WO 2 WO 2 E01 E02 E02 WOl WO 7 WO 7 WO 8 WO 6 WO 6 WO 7 WO 8 WO 5 WO 6 WO 7 WO 7 WO 8 WO 8 W06. W07 Thickness Structure 06 07 36 16 19 02 11 33 29 01 08 03 12 31 08 01 08 850 854 890 824 820 869 809 840 759 731 730 845 833 774 685 706 650 -1554 -1418 -1500 -1371 -1200 -1576 -1466 -1460 -1300 -1268 -1200 -1541 -1500 -1454 -1300 -1245 -1141 11 28 03 28 02 15 06 05 34 15 19 27 23 19 22 21 33 36 34 14 11 10 19 27 14 28 18 12 1014 1070 1075 1030 1030 1042 1005 1005 1008 1033 1042 1040 995 800 820 774 885 908 837 808 957 903 810 811 812 792 857 860 -1700 -1664 -1732 -1689 -1685 -1606 -1720 -1700 -1634 -1822 -1844 -1800 -1755 -1270 -1270 -1194 -1272 -1261 -1269 -1132 -606 -751 -951 -975 -961 -916 -666 -685 153 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 Permit Number Location 20931 19429 23585 13981 16481 19380 8123 13864 10451 3112 11409 11565 13288 16820 16273 7560 20521 21158 27505 11835 20683 18555 3310 15690 11919 13959 20004 17732 N09 N09 N09 N09 N09 N10 N10 N10 N10 N10 Nil Nil Nil Nil Nil Nil Nil Nil N12 N12 N12 N12 N12 N12 N12 N12 N12 N12 WO 5 WO 5 WO 6 W06 W07 WO 5 WO 5 WO 6 W07 W08 WO 5 WO 6 WO 7 WO 7 WO 8 WO 8 WO 9 Wll WO 5 WO 5 WO 6 WO 6 WO 7 WO 7 WO 8 WO 8 WO 9 W10 10 25 01 36 26 04 21 13 13 23 08 02 01 26 07 33 16 14 08 36 09 27 06 26 03 06 08 07 1090 1096 1091 1075 984 1040 1059 1050 1013 942 1012 1054 1015 1012 910 1000 871 875 1002 996 977 988 996 1017 934 928 839 808 22722 19486 24158 7468 3605 7636 20151 14740 15296 16316 18553 8860 15374 11999 27497 N09 N09 NO 9 N09 N09 N09 N10 N10 N10 N10 N10 N10 N10 N10 N10 W14 W14 W15 W15 W16 W16 W13 W13 W13 W14 W15 W15 W16 W16 W17 17 28 11 28 20 35 03 18 33 15 03 34 05 23 10 658 645 622 625 580 590 672 640 657 658 638 605 587 580 570 Thickness IUSK 525 526 527 528 529 530 531 532 533 534 535 536 537 530 5*3? 154 J Jap. _ Number SfJSUii Number Location 15820 14620 15364 25472 26783 18227 15995 15789 8193 14982 20084 Nil Nil Nil Nil Nil Nil N12 N12 N12 N12 N12 W15 W16 W16 W17 W17 W18 W15 W15 W16 W17 W18 23 03 19 15 32 13 09 19 05 03 12 655 612 580 567 554 585 615 640 596 550 540 -472 -371 -358 -340 -262 -300 -485 -447 -415 -300 -210 IEWAYGO 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 19331 10778 23149 12128 6045 14415 17331 434 12815 12961 16042 19028 18604 9443 25189 411 20406 22866 10683 24988 17183 20002 26487 16801 26666 27173 95192 27850 15997 15649 16239 Nil Nil Nil Nil Nil Nil N12 N12 N12 N12 N12 N12 N12 N13 N13 N13 N13 N13 N14 N14 N14 N14 N15 N15 N15 N15 N16 N16 N16 N16 N16 Wll Wll W12 W13 W14 W14 Wll W12 W12 W13 W13 W14 W14 Wll W12 W13 W14 W14 Wll W12 W13 W14 Wll W12 W13 W14 Wll Wll W13 W14 W14 07 12 10 35 14 29 20 05 21 10 19 04 23 03 03 12 16 26 07 19 32 05 25 11 17 16 07 28 23 18 33 804 860 710 704 654 634 729 700 706 676 652 630 617 750 685 650 622 625 735 685 642 600 750 641 634 584 636 643 609 623 614 -966 -1040 -900 -741 -587 -488 -946 -850 -885 -724 -677 -567 -659 -1050 -960 -830 -646 -663 -1000 -800 -700 -500 -1160 -973 -663 -559 -1035 -1062 -000 -440 -531 )AKLAND 582 583 18766 9719 N02 E07 25 N02 E07 32 540 541 542 543 544 545 546 547 548 549 550 Thickness Structure +600 +688 155 Map Numb Number Location Thickness 584 585 586 587 588 589 590 591 592 593 9262 23407 22665 9751 13072 12454 23655 7798 26658 26436 N03 NO 3 N04 N04 N04 N04 N04 N05 NOS N05 E07 Ell E07 E08 E08 E09 Ell E09 Ell Ell 18 01 09 02 22 16 08 15 08 14 OCEA 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 19099 20027 8331 17201 14328 18340 11294 22494 20238 23128 20684 17758 24241 15681 19688 20881 15059 23765 N13 N13 N13 N13 N13 N14 N14 N14 N14 N14 N14 N14 N15 N15 N16 N16 N16 N16 W15 W16 W16 W17 W18 W15 W15 W16 W17 W17 WlB W19 W16 W18 W15 W16 W17 W17 09 19 23 26 09 24 28 21 06 10 11 13 28 23 22 25 05 13 595 568 600 539 OGEM 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 12267 16723 4830 14832 19978 18508 1770 19167 4753 1143 14474 5264 3825 8213 17239 23711 N21 N21 N21 N21 N21 N21 N22 N22 N22 N22 N22 N23 N23 N24 N24 N24 E01 E01 E02 E03 E03 E03 E01 E02 E02 E04 E04 E02 E03 E01 E02 E03 08 15 02 03 16 36 23 18 33 16 25 05 29 08 18 04 1082 1111 Structure +252 +500 -112 -100 +62 +46 +100 -147 -35 0 610 590 560 561 570 533 579 570 550 1156 1074 1100 1109 1224 -526 -410 -500 -325 -147 -600 -570 -442 -300 -329 -241 -144 -430 -200 -351 -300 -100 -187 -1044 -993 -283 -700 -427 -322 -421 -310 -261 -563 -682 -293 -387 -400 -304 -431 156 Map Numb Number Location OSCE 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 15489 18068 18778 6838 27578 5572 20395 9918 15915 23121 25862 16379 10159 9434 26157 26254 18698 14405 18709 N17 N17 N17 N17 N17 N18 N18 N18 N18 N18 N19 N19 N19 N19 N19 N20 N20 N20 N20 OSCO 647 648 649 12242 18586 25175 N25 E02 22 N25 E03 34 N26 E01 09 OTSE' 650 651 652 653 654 655 656 17787 17455 16183 26216 25873 18467 20543 N29 N29 N29 N29 N29 N30 N30 WOl WO 2 WO 2 WO 3 WO 4 WOl WO 3 13 10 16 16 02 10 21 9738 7833 5162 19398 9589 14697 20414 26332 8141 5557 5629 N05 NOS N05 NO5 N05 N06 N06 N06 N07 N07 N07 W13 W13 WO4 W14 W15 W13 W14 W15 W13 W14 W15 21 35 10 21 09 21 21 26 08 16 23 OTTA 657 658 659 660 661 662 663 664 665 666 667 W07 W08 W08 W10 W10 W07 W08 WO9 W10 W10 WO7 WO8 WO9 W10 W10 WO7 WO8 WO9 W10 11 08 14 08 31 10 35 28 17 26 17 15 01 02 27 05 18 26 15 Thickness Structure 818 743 777 662 644 804 802 685 614 634 806 772 750 662 655 800 761 690 654 -1541 -1412 -1481 -1057 -1100 -1600 -1420 -1255 -1000 -1132 -1548 -1500 -1300 -1100 -1047 -1342 -1200 -1100 -1000 -446 -500 -500 60 200 148 269 386 378 241 768 765 715 682 650 729 683 647 728 651 620 -247 -235 -229 -155 -124 -355 -227 -200 -472 -336 -256 157 i JaPK Number SerI!it Number Location 668 669 670 671 672 673 5888 7099 6592 19373 15837 19745 N07 N08 N08 N08 N09 N09 W16 W13 W14 W15 W13 W13 13 07 35 04 15 28 582 703 658 592 676 684 -200 -500 -442 -370 -635 -575 tOSCOMON 674 675 676 677 678 679 680 681 682 683 684 4270 16985 9616 5221 18973 5941 4603 8625 15756 10241 26722 N21 N21 N21 N22 N22 N22 N23 N23 N24 N24 N24 WOl W03 W04 WO2 W02 WO4 W02 W04 WOl W02 W04 36 29 32 06 28 28 26 31 20 16 22 1050 960 914 1050 1007 955 1075 1009 1085 1052 1015 -1337 -1443 -1523 -1169 -1200 -1233 -996 -1079 -400 -428 -610 SAGINAW 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 9273 95235 10355 3581 95145 3148 95236 20583 4099 6535 19538 15019 19363 2683 95642 11347 12262 N09 N09 N09 N09 N10 N10 N10 N10 Nil Nil Nil Nil N12 N12 N12 N12 N13 E01 E03 E04 E04 E02 E03 E04 E06 E01 E02 E03 E04 E01 E02 E04 E05 E04 10 13 11 32 28 11 14 10 33 11 17 28 02 31 14 35 33 968 -1321 -1128 -1074 -1000 -1328 -1284 -1158 -968 -1465 -1400 -1368 -1300 -1580 -1481 -1200 -1174 -1300 ST. CLAIR 702 703 704 705 706 707 708 709 22468 22409 26903 27872 25593 25841 25859 24274 N06 N06 N06 N06 N07 N08 N08 N08 E13 E13 E14 E15 E13 E13 E14 E15 08 33 11 29 22 12 19 33 991 950 995 975 1011 • 981 1028 1025 1030 980 +67 +145 +270 +370 0 -114 -70 +190 158 X b e r E e r location ST. JOSEPH 710 711 712 713 714 715 18405 17184 24183 1244 14283 7045 S05 S05 S06 S06 S06 S07 WO9 W12 W09 Wll W12 W12 02 03 29 02 09 10 +110 +276 +262 +320 +324 +463 SANILAC 716 717 718 719 720 721 722 723 724 725 726 727 728 24220 24346 22856 22857 18725 10921 23769 10386 23500 23616 24139 23583 24047 N09 N09 Nil Nil Nil N12 N12 N13 N13 N13 N13 N14 N14 E14 E15 E12 E14 E15 E13 E14 E12 E13 E14 E15 E12 E15 08 31 25 07 05 02 27 14 20 06 34 28 21 -188 +70 -555 -215 +185 -140 -32 -330 -205 -170 +260 -541 0 SHIWASSEE 729 730 731 732 733 734 7013 8214 1570 14349 9396 21026 N05 N06 N06 N07 NO 8 N08 E03 E02 E03 E02 E01 E04 08 35 11 03 04 01 -300 -400 -566 -1000 -1300 -900 13821 20209 4943 12808 19757 15817 21169 18882 20159 N10 N10 Nil N13 N13 N13 N14 N14 N15 E07 E09 E08 E09 E10 Ell E07 E09 E08 28 05 32 04 29 05 15 10 29 !USCOLA 735 736 737 738 739 740 741 742 743 rAN BUREN 744 745 746 Thickness 1085 1074 1050 1030 1167 1084 1147 1165 Structure -755 -730 -856 -869 -1042 -574 -830 -930 -970 » 8533 59580 5697 SOI W14 01 SOI W14 08 SOI W15 09 +100 +137 +135 159 Map Number Permit Number Location 747 748 749 750 751 752 753 754 755 756 757 758 10866 15601 5363 10752 19370 7999 25991 24819 6533 8442 19190 25679 SOI SOI S02 S02 S02 S02 S03 S03 S03 S04 S04 S04 W16 W17 W13 W14 W15 W16 W13 W14 W15 W13 W14 W15 36 22 21 20 21 21 19 10 13 05 24 29 +200 +200 +100 +168 +203 +245 +258 +232 +245 +300 +322 +396 WHASTEMAW 759 760 761 762 763 764 765 21477 19371 10792 19751 18945 19202 18886 SOI SOI SOI S02 S02 S02 S04 E03 E05 E07 E03 E04 EOS E04 06 33 33 14 30 28 21 +52 +132 +460 +200 +222 +480 +365 WEXFORD 766 767 768 769 770 771 772 773 774 775 23837 11755 16018 10181 25348 4584 10245 12415 10303 26022 N21 N21 N21 N21 N22 N22 N22 N23 N23 N24 WO 9 W10 Wll Wll W09 WO 9 W10 WO 9 Wll WO 9 28 21 23 29 13 17 30 32 11 20 Thickness 693 661 645 668 719 706 718 658 Structure -1000 -900 -857 -771 -1000 -856 -778 -840 -479 -544