A STUi‘DY '3: (2511.513? ECS EN TNE NEfiAUNEE {RON @Q-EMJ ?§CN NE. 4.? 3%“; R, [RICE “EGAN 1" 1:28:53 1121‘ £1.19 Mr” 0: if. 3. 'F? f“-"'[" Fri" a. n ram 2" :07?! '1: mr :‘2 “a xvi“ 1H 3’- - 83112 ’ L.Vs-.l.bl‘u U u (‘4‘ B .‘ AK 1 “\RWWM“ .2333 51; University By i\ .( Robert Wf‘Henny A'THESIS Submitted to Michigan State University Qia partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of GeOIOgy 1970 gsrtbnehouse and J. W. Trow for their helpful assistance through- :11. r7115 study. “5‘54 appreciation is expressed to J. T. Mengle for the many I‘ ' ytfiiscussion in the field and for the use of thin sections 11 ‘ ABSTRACT An investigation was conducted on the relationships between a number of elastic lens—shaped bodies and a portion of the Negaunee Iron Formation. The principal study area was located at the abandoned Moore Mine in the Palmer Range, a downfaulted block on the southern flank of the Marquette Synclinorium. approximately 12 miles south of Negaunee, Michigan. Here the iron formation is continuously exposed in cross-sectional profile along its strike for a distance of 0.3 mile. More than forty elastic lenses ranging from a foot to over three hundred feet in length and up to fifty feet in width were mapped in detail. The depositional relationships between the lenses and the iron formation are varied; the majority of lenses are essentially conformable with the iron formation. Some of the conformable lenses are gradational at their lateral boundaries, some exhibit miniaturized on-lap off-lap features. while others have merely warped the under- lying layers of iron formation. The unconformable lenses are of three types: channel fills, isolated blocks, and oblique gradations. fi.‘ The iron formation contains a two percent background of rounded sand grains which are equally dispersed among the chert and hematite layers. This percentage of sand grains is observed to increase notice- ably when a elastic lens is approached from beneath. The elastics consist of metamorphized mixtures of rounded and angular fragments of chert, hematite, quartz, quartzite and granite, together with varying quantities of sand all in a matrix consisting of varying proportions of shale. chart and hematite. Petrographic and binocular analyses were used to divide the clastics into five lithological groups and a number of sub-groups on the basis of their mineralogical and textural characteristics. It is deemed significant that only one lithology is found in a given lens and that a particular lithology always maintains the same depositional relationship with the iron formation. A method for chemically disaggregating some of the elastics was developed enabling roundness, sphericity, and size distribution analyses to be made. Results showed the sand grains to be similar to those found in typical beach washed sands. Using the above relationships. mechanisms of deposition are postulated for each lens type. The analysis is then extended to several other elastic zones in the immediate vicinity with areal ! correlations made. Conclusions would support a shallow water environment of -dep05ition where chert and-hematite were deposited in alternating iii er proper environmental conditions. The major source ' Hell worked sediments prior to their transportation into f§§h. Reiworked beach sands were regularly supplied to the e“ ile occasionally off-shore currents created lenses and beds 'out into the basin. The dispersion of these sands appears w: transport. Finally at a few localized areas large masses (.tics were rapidly deposited via slides and/or turbidity currents. iv TABLE OF CONTENTS Section Page I I INTRODUCTICI‘: I I I I I I I I I I I I I I I I I I I I I I I I 1 AI Pr0blem I I I I I I I I I I I I I I I I I I I I I . I I 1 B . Approach I I I . I I . I I I I I I I I I I . I I I I I I 2 'CI StUdy Location. I I I I I I I I I I I I I I I I I I I 2 D. Previous Investigations . . . . . . . . . . . . . . . . 3 11 I REIOIqAL G EOLCC‘IY I I I I‘ I I I I I I I I I I I I I I I I I I 12 A. General I I I I I I I I I I I I I I I I I I I I I I I I 12 B. HethOd Of Survey. I I I I I I I I I I I I I I I I I I I 12 CI HethOd Of Plotting. I I I I I I I I I I I I I I I I I I 15 DI Topography. I I I I I I I I I I I I I I I I I I I I I I 15 E. Structure I I I I I I I I I I I I I I I I I I I I I I I 16 F I Straiti gmphy I I I . I . I I I I I I I I . I I I I I I I 19 III. CLASTIC-IRON FORMATION RELATIONSHIPS AT THE MOORE MINE. . . 33 A. General I I I I I I I I I I I I I B. Napping Procedure I I I I I I I I I I I I I I I I I I I 35 C. Sample Collection and Preparation . . . . . . . . . . . 36 DI‘ Sample Analyses I I I I I I I I I I I I I I I I I I I I 37 E. Sample ClaSSification I I I I I I I I I I I I I I I I I 51 F. Lens Descriptions I I I I I I I I I I I I I I I I I I I 65 G. CObble Zone I I I I I I I I I I I I I I I I I I I I I I 9# HI Iron Formation. I I I I I I I I I I I I I I I I I I I I 99 II PerCIaStiC Horizon I I I I I I I I I I I I I I I I I I 103 IV. CLASTIC HORIZON I I I I I I I I I I I I I I I I I I I I I I 106 AI General I I I I I I I I I I I I I I I I I I I I I I I I 106 BI Location Descriptions I I I I I I I I I I I I I I I I I 108 F CI correlation I I I I I I I I I I I I I I.I I I I I I I I 11“ VI SUMMARY AND DISCUSSION. I I I I I I I I I I I I I I I I I I 11? A. Geologic History. . . . . 117 B. Provenance. I I I I I I I I I I I I I I I I I I I I I I 119 CI DisperSIOHI I I I I I I I I I I I I I I I I I I I I I 121 ‘Do Depositional Environment. I I I I I I I I I I I I I I I 123 VII CON CLUSICNS I I I I I I I I I I I I I I I I I I I I I I I I 135 Ramflics I I I I I I I I I I I I I I I I I I .I I I I I I I 13? APPEDIX A I I I I I I I I I I I I I I I I I I I I I I I I I 1’41 LIST OF TABLES Page ' Ronndness and Sphericity Data. . . . . . . . .'. . . . . b? .Data Composite - Percent Heavies, HCl Solubles and KOHSOIubl-BSIIIIIIIIOIIIIIIIIIIII 1‘9 ._Summary of Sample Classification Data. . . . . . . . . c 52 .'c1ast1cLensData.................... 68 T'Glestic Lens Data Summary. . . . . . . . J . . . . . . . ' 71 élasticflorizonData...-............... 115 Tiansport Velocity Index for Clas ice at the . xnooremneIIIIIIIIIIIIIIII‘IIIIII 133 .,€; -- fi=i§ . That Results - Effect of HCl and KOH Solutions on Send . 155 LIST OF FIGURES Lacation and Geology of the Palmer District (after Van Hise and Leith, ref. 1) with Present Study Areas Outlined I I I I I I I I I I I I I I I I I I I I I I a Point Diagram of 300 Joints from Lens #2, Moore Mine with Regional Structural Features Superimposed . . . . . . 18 Size Distribution Histograms of Sieved Samples . . . . . . . #3 Cumulative Size Distributions of Sieved Samples. . . . . . . an Roundness and Sphericity Histograms. . . . . . . . . . . . . ”6 PhotomicrOgraph of a CQA Specimen Showing Sand Grains Floating in a Chert (m saic) and Hematite (opaque) Groundmass, Crossed NiCOlS, 10X. I I I I I I I I I I I I I 5? CQA Semi-polished Specimen with Etched Surface Showing Close Packing of Sand Grains, 2X . . . . . . . . . 57 Cg? Semi-polished Specimen Showing Interbeds of Chert light) Hematite (dark) and Sand Grains in a Chloritic Cherty Fatrix, ZXI I I I I I I I I I I I I I I I 59 Q3 Semi-polished Specimen Showing Apparent Lineation and Corrosion of the Quartz Grains, 2X . . . . . . . . . . 59 } 10. Typical CQSA Semi-polished Specimen Showing Sub-rounded Fragments of Q5, Chert and Sand Grains in a Sericitic Chert Matrix, 2X I I I I I I I I I I I I I I I I I I I I I 62 11. Semi-polished CQSA Specimen Showing Turbulent Textures Common Near Lower Boundaries of Lenses. 2X . . . . . . . . 62 12. Semi-polished CQSC Specimen Consisting of Assorted Fragments (mostly sand grains) in a Sericitic Matrix. 2X I I I I I I I I I I I I I I I I I I I I I I I I 66 13. Clastic Lens #2 Looking North from the Southern Edge . . . . 74 1h. Joint and Fracture Controlled Hematitic Staining in Lens #20 I I I I I I I I I I I I I I I I I I I I I I I I I 7h 15. Clase-up of Lens #2 Showing Rectangular Cobble and Numerous Pseudo-pebbles. I I I I I I I I I I I I I I I I I 80. 1 l vii LIST OF FIGURES (cont.) “xqgf Page qglqstic Lens #8 with Center Indicated by Hammer. . . . . . . 80 ,1 figphble Lens #19 with Base to the Top and Left of PhOtOSraph I I I I I I I I I I I I I I I I I I I I I I I 0.85 .~101ose-up of Cobble Lens #19. . . . . . . . . . . . . . . . . 88 vii» Clastic Lens #28 . . . . . . . . . . . . . . . . . . . . . . 88 viliflohble Lengths and Widths. . . . . . . . . . . . . . . . . . 96 Cdbblo Roundnesses and Sphericities. . . . . . . . . . . . . 97 rrlnclination of Long Axes of Cobbles with Respect to Iron Formation Bedding I I I I I I I I I I I I I I I I I I 98 “-contorted Bedding in the Iron Formation. . . . . . . . . . .101 . Clastic Horizon Map. .‘. . . . . . ... . . . . . . . . . . .107 .‘Ifiealized Sketches of Clastic Lenses . . . .‘. . . . .-. . .127 ‘Pbrcent Weight Loss for Various KOH Solutions as a ‘ Function of Boiling Time .'. . . . . . . . . . . . . . . .150 viii LIST OF MAPS (located in map pocket) : 7 " Geologic Map . :lino‘ Hap {9"31‘" _’ ‘ Ari ZX'I‘ 75-3! ' NOTATIONS fl? .éfiy‘rty sericite V 1}" {EMMY quartzite ‘ r9011.” sericitic quartzite "gar-tile kurtosis . arithmetic mean [radian fieonetnc mean Lame dimension . filthmetic quartile deviation Ericitic quartzite ' :2“, mm deviation . F139“ , ‘grlthnetic skewness , g_etri_¢: skewness ‘ . . Jw diameter '0”.- Q N I I } SECTION I INTRODUCTION A. Problem During the past 100 years there has been a continuing controversy concerning the Precambrian Iron Formation Problem. Debate has been centered around questions involving the location and lithology of the source rock, the mechanics involved in extraction and concentra- tion of the source material, the transport mechanisms, the physical and chemical environment during deposition and the processes responsible for post-depositional alteration. Although there have been numerous investigations directed toward the Problem, the Problem remains basically unsolved. Perhaps a prime reason for this state of affairs is the fact that there is no Precambrian type iron formation being deposited today and there has been none deposited since Precambrian times. During the summer of 1959 the writer, while attending the Michigan State University Geology Field Camp, was introduced to the Precambrian rocks surrounding Marquette Michigan including the Negaunee Iron Formation, a chemically deposited unit consisting principally of inter- bedded layers of hematite and chert. A particularly interesting feature of a portion of the Negaunee Iron Formation is the occurrence rof interbeds, lenses and inclusions of various kinds of elastic .sediments. 3. Approach It is the author's Opinion that by applying modern sedimentary principles to these clastics certain conclusions concerning their origin can be drawn, conclusions which in turn should be pertinent to the origin of the iron formation itself. It is the objective of this theSis to obtain information on the geologic history, provenance, dispersion and physical environment affecting the accumulation of elastics in a portion of the Negaunee Iron Formation. Following the selection of the study area the investigation was conducted in three lOgical steps, results of which are presented in Sections II, III and IV respectively: (1) A regional study to determine the geology and structure of the area and in particular to ascertain the lithologics present prior to Negaunee Iron Formation deposition (2) A detailed analysis of a suite of elastic deposits and their relationships to the surrounding iron formation to determine the mechanics and environment of deposition. (3) A correlation of elastic deposits along a broad horizon to determine the dispersive nature of the elastic deposition. 0. Study Location The Moore Mine, located within the Negaunee Iron Formation on a down-faulted block (Palmer District) of the southern limb of the marquette Synclinorium in the Upper Peninsula of Michigan, was selected for the detailed study portion of this research for the following reasons: (1) Large quantities of a number of different types of clastics are preserved in cross section. (2) There is clOSe proximity to the base of the iron formation. (3) There are excellent exposures in three dimensions. (4) There is relatively uncomplicated structure and strati- sraphy- . (5). The area is readily accessible. The Moore Mine is located in the south-central portion of section 28, Th7N, 326w, Michigan. rThe area of regional study includes sections 27, 28, the north one-half of 32 and 33, and portions of 26, 34, and 35. Figure 1 gives the location and general geology of the Palmer District after Van Rise and Leith (l)*. The present study areas are outlined where the roman numerals correspond to the appropriate maps: I-Regional Geologic Map (Map I), II-Moore Mine Map (Map II) and III—Clastic Horizon Map (fig. 2h). Maps I and II are located in the map pocket. D. Previous Investigations It is intended to review briefly those articles which in the author's opinion represent milestones in the development of thought on the origin of the iron formation in the Palmer District. Refer- ences prior to 1897 have been extracted from Monograph 28 "Marquette Iron-Bearing District of Michigan" by Van Hise and Bayley (2). L' During the year 1820 Henry Schoolcraft (3) traveled along the Michigan shore of Lake Superior. Included in his subsequent report, *Numbers in parantheses refer to similarly numbered entries in the reference section. \\\\\\N\\\\\\\ [Oil loll-Ir. ‘1‘“ - tad Figure 1. Location and Geology of the Palmer District (after Van Rise and Leith, ref. 1) with Present Study Areas Outlined the first reference to the geology of the Marquette Region is found. From 1820 on there has been an ever increasing flow of literature published dealing with the numerous geological problems of the Marquette District. The occurrence of hematite in the Marquette Area was reported in lehl by Houghton (h) - "Although the hematite is abundantly dissemi- nated through all the rocks of the metamorphic group, it does not appear in sufficient quantity at any one point that has been examined to be of practical importance". In 18n6 a comprehensive geological survey of the Lake Superior district in Michigan was initiated for the United States Treasury Department under the direction of Dr. Jackson. Two years later the first report (5) under this program was published by Locke; in the report he refers to a number of very pure iron ore deposits in the area which is now occupied by the t0wn of Negaunee, particular emphasis was made to the ore at the then operating Jackson Mine. Burt, working under Jackson, also issued a report that year although not published until 1850 (6). After studying some fourteen exposures of iron ore along his traverses he concluded that the region contained the greatest abundance of high quality iron ore in the United States. Another of Jackson's assistants, J.H. Foster, provided the first ideas as to the origin of the iron formation when he stated that they derived their origin from "aqueous" causes while "igneous" causes have since operated to modify their character. This report is dated 1850 (7). In that same year Foster and Whitney succeeded Jackson at the helm of the survey. Three years later they published a paper summing up their work on the Lake Superior Region in connection with the . Chippewa Land District Survey (8). This report presents the first detailed study of the geological relationships; the rocks are classified and a rather detailed map is presented. Concerning the iron ore, they state that it is igneous material although some action of segregation was present during and after deposition. These segregating forces were needed to explain the banded nature of the jasper ore, however, they refuse to accept a sedimentary origin for the jasper - "at first glance the banded structure might be regarded by some as the result of aqueous deposition "...but..."if these were really the result of aqueous deposition we should expect from analogy with other deposits of similar character that some of the layers would be of more considerable thickness than others"...and..."in some cases at least the foldings would exhibit a considerable radius of curvature, which is not the case here." The first definite statement favorinv sedimentary deposition for the iron ores was published in 1865 by Kimball (9) where he concluded that since the iron formation was intimately associated with the other sediments it therefore must have undergone similar conditions of deposition. A pyroclastic origin was prOposed by Daddow and Bannan (10) a year later in which they conclude that the iron ores are volcanic in origin but sedimentary in deposition. In 1882. Columbia University published a report describing the iron formation near the Champion Mine as being deposited in an E-H trending river or series of lakes (ll). Rominger (12) as State Geologist of Michigan, published a compre- hensive report dated 1881 on the lithological and structural relationships in the Marquette Synclinorium. This study stood as.a basic refer- ence until the publishing of U.S.G.S. Ronograph 28 in 1897. Reference is made to the Palmer geology and to the granite knobs in section 22 and 23. Winchell (13) made an important contribution to the stratigraphy of the area when in 1887 he described a conglomerate (Goodrich Conglomerate) near Palmer as containing jasper, chert, and hematite pebbles. Although this same conglomerate was described by Foster in 18h9, Winchell was the_first to recognize ts unconformable relation- ships to the underlying iron formation. The iron formation..."must have been constituted in pretty nearly its present state prior to the formation of the conglomerate." Wadsworth, the last major proponent of the igneous origin for the iron formation was converted in 1892 (lb). He published a paper stating that the sedimentary origin of the Jaspilites is plainly shown in the Cascade Range, south of Palmer, where they are found intermixed with quartzites. Most of the interlaminated jaspilites appear to be composed of fine jaspilite derived from parent debris. In 1897, Van Hise and Bayley (2) published a monumental work - honOgraph 28, "Marquette Iron-Bearing District of Michigan," which is still considered a standard reference for the area. .The main body of the report is concerned with. the detailed description of the various formations in the Synclinorium, their distribution, top05raphy, structure, thickness, petrographic characteristics, relation to other formations, descriptions of particularly interesting locations, etc. The Palmer District is described as a detached appendage of the (ngquette Synclinorium preserved due to down—faulting. Only the Ajibik, Siamo, Negaunee, and Goodrich formations were found in the area, all lying unconformably upon the Archean Basement. Of particular interest is the Palmer Gneiss which is described as a highly schistose, strongly foliated rock with varying amounts of quartz in a "hydromicaeceous" groundmass showing much mashing. When the quartz is in excess it approaches a "squeezed" quartzite, when not it approaches a fine grained gneiss. This inability to distinguish in the field between some of the phases of the Palmer Gneiss and ordinary quartzite, coupled with the fact that even when studied in thin section the gneiss can often be equally well described as silicified, weathered granite or as granitized quartzite has provided Va fundamental basis for the Palmer Gneiss dispute. After noting that the Palmer Gneiss is never observed grading into the overlying for- mations, Van Rise and Bayley concluded that the gneiss is a silicified, weathered granite of Archean Age. Other interesting localities discussed include the Ajibik Hills, the north block of the Volunteer fault and the type location for the Ajibik Quartzite. The Negaunee Iron Formation in the Palmer District is described as being no different frOm that in the main synclinorium except that in the lower horizons fragmental quartz is seen as individual grains and in small beds. An excellent exposure of the Goodrich conglomerate is noted south of the town of Palmer. The United States Geological Survey Monograph 52, ”The Geology of the Lake Superior Region," was published in l9ll-by Van Rise and Leith (1). In the chapter on the Marquette District little is changed from.the earlier monograph. The Palmer Area, however, was significantly reinterpreted. The quartzite forming the Ajibik Hills was renamed the Hesnard and it was indicated that the Palmer Gneiss contains some pockets of Huronian sediments. Structurally the Palmer and Volunteer faults were identified. Another large chapter is devoted to iron ores in general including discussions on the conditions of deposition, the chemistry of the ores, their alterations and the method of secondary concentration. Between 1931 and 1937, Laney (15, 16, 17, 18, 19, and 20) published a number of papers principally concerned with the geological inter- pretation of the Southern Complex and in particular with the Palmer Gneiss. After considerable field and laboratory study he reached the conclusion that some of the rocks delineated as Palmer Gneiss were actually metamorphosed Lower Huronian sediments and that this meta- morphism occurred by intrusion of the Republic Granite during the interval between Lower and Middle Huronian. Dickey (21. 22) took exception to Lamey's conclusions regarding the Republic Granite and pointed to other evidence which he believed indicated that the major portion of the Southern Complex was composed of pre-Huronian granites. Tyler and Twenhofel in 1951 (23) reported on the Marquette District: they presented their views on the environmental conditions governing the deposition of each of the lithological units. 'In particular they refer to the iron formation in the Palmer District as the GOOse Lake Iron Formation, a unit of the Siamo Slate. This has since been shown to be in error. They also state that there is no evidence for an unconformity between Lower and Middle Huronian. 10 Marsden (2“) made minor contributions to the stratigraphy of the Palmer District in 1955. In 1956, Vickers (25) identified monazite as occuring in quartzite near Palmer and also at the New Richmond Mine associated with feldspar clastics, indicating that pegmatites ‘1ocally contributed debris to the sedimentary basin. In 1956, Mengle (26) studied the clastics in the Palmer District and specifically at the Moore Mine. He mapped iron formation - elastic relationships at the Moore Mine and speculated as to the conditions of the iron and chert during deposition. Considerable study was also devoted to the nature of the iron formation in the area. Mengle's work represents the best summary of the clastic — iron for- mation relationships to date. Sahakian (2?) studied a portion of the Palmer Gneiss situated several miles east-southeast of the {core Mine. A petrOgraphic and structural analysis indicates similarity to the granite knobs a few miles north, in section 22 and 23. During the summer of 1958, Long (28) studied a portion of section 3h in the Palmer District. He identified a green slatey material cut by an orange granite which in turn was cut by an early Keweenawan type dike. The granite was believed to have undergone a major period of deformation and was placed as Huronian in age. Rosenberger (29) in 1960, mapped sections 22 and 23 where he found the hills designated as Palmer Gneiss eroded and overlain by Mesnard Quartzite. The base of these hills contained a large number of granite cobbles. His findings indicate that the Palmer Gneiss, at least here, 11 "ed the Lower Huronian. In the Mesnard formation he was ’ Jthentiate three distinct members, a. slate, a. slate ‘3, and a. true quartzite. ' f... ; ‘ht’ .4 in Vors.‘ ‘ S'J r-‘ 'I'. LIIB Ha. L.‘ ‘J - zlt'z'er 1' dim-dial- 7f" —. .— I zed- Arzw'd‘x .- . y , Griz). § “”5315 “- ‘ "' 3 ) — C 12 SECTION II REGIONAL GEOLOGY A. General During the summers of 1960 and 1961, field crews from the Michigan State University Geology Field Camp were stationed at Northern Michigan College, Marquette, Michigan. Under the direction of Dr. Justin Zinn and the author, several sections in an area east of Palmer, hichigan were mapped as part of a regional geologic study of that portion of the Palmer District. Specifically, the area studied included sections 27 and 28, the northern one-half of sections 32 and 33, part of section 34, and the adjoining corners of sections 26 and 35, all located in Th7N, R26W, Michigan. Work completed on sections 27, 28, 32, and 33 is compiled from the field notes of the Michigan State University field crews. The portion in section 34 is taken unmodified from a 1959 unpublished master's thesis by Long (28). The controversial outcr0ps in the west corner of sections 26 and 35 were first mentioned by Laney in 1935 (19). Due to their stratigraphic significance this writer re—examined the outcrOps in 1961 and included the observed relationships in the regional map. See figure 1 for location of the reoional study area (I). 3. Method of Survey The surveying was carried out by pace and compass using either a Brunton or sun-dial compass depending upon the local magnetic inter- ference encountered. Approximate mean declination in the area is l/QOW (USGS, 1952), a negligible value for such methods. The in standard pacing technique was used where 2,000 paces are set equivalent to a mile, resulting in a pace equal to 2.63 feet - the standard pace. The sun compasses were checked along a north-south line established by the author near the site of the Isabella Mine just south of Palmer and about two miles west of the sections mapped. The following restrictions were placed upon sun compass use to insure reliable readings: (1) Compensation curves were computed for each instrument and used throughout the surveying period. (2) Each morning prior to beginning field work the compasses were checked against the established north-south line. (3) Use of the sun compasses was restricted to the middle seven hours of each day. (h) Sun compasses were checked against the north-south line at the end of each day. The Brunton compass indicated one major and several minor magnetic disturbances over the area mapped. The principal anomaly was located in the southwest corner of section 28: it is believed to have been caused by magnetite banding in the Ajibik, (see Section II-"). Topographic maps and aerial photos of the area were carefully studied before going into the field. In the field all section corners were found and positively identified with the exception of the northwest corner of section 32. Base lines were laid off along the north and south section lines, on which the intersection of planned traverse lines were marked; these were later used to'correct for the traverse- line drift. Eight north-south traverses were run per section taking maximum benefit of the east-west topographic tren s 15 Each crew consisted of at least four men: a pacer, a compass man Who was also party chief, and one geologist on each side of the traverse line. Outcrop locations were accurately recorded in the field notes together with their descriptions, strikes, dips, and general trends. Samples were taken from each outcrOp for further study with a binocular microscope at field camp headquarters during the evenings, after which representative samples were indexed and stored for later study. Location of cultural objects (houses, roads, railroads, mine pits, etc.) and topographic features (swamps, rivers, fault scarps, hills, etc.) were recorded in the field notes to aid in plotting and interpretation of the traverse data. 0. Method of Plotting All outcrops on the regional map were replotted from original notes on a base map prepared from the U.S.G.S. and U.S.C. & G.S. Palmer Quadrangle map of 1952, 7-1/2 minute series. Distances between cultural points were measured from the Palmer Quadrangle map. Differences between these and paced distances were computed and drift curves prepared for each traverse assuming a linear error between control points. Outcrops were plotted on the actual traverses paced, as determined from starting and finishing points of each traverse and again assuming a linear error. Where areas of continuous Outcrop existed-osuch as hills, fault scarps or iron mine excavations-~cnly one outcrop was plotted covering the entire area. A total of over 700 outcrops are identified and plotted on the regional map. ' D. Tepoggaphz The major tepographic feature in the area mapped is the prominent ’Vglunteer Fault trending east-west along the northern parts of sections é.‘ V .16 2? and 28 where it is exposed as a lSO-foot near—vertical cliff. A series of parallel faults cause the land surface north of the main fault scarp to rise in step-like fashion, forming the imposing Ajibik Hills. Immediately south of the fault lies an extensive. swampy grassland drained by a few sluggish streams. This covers the central portions of sections 2? and 28. Further south the land rises out of the swamp becoming a hilly terrain continuing south well beyond the area studied. Glaciation is in marked evidence throughout the area. Glacial grooves extensively mark the racks to the north and south of the swamp area. Drift cover probably begins in the swampy areas and becomes noticeable as it thickens towards the east where sand plains euentually cover all outcrops. The tOpographic trend is then east-west, with low land in the middle and high land flanking to the north and south. With few exceptions. outcrOps are found only in the high land. mm The Palmer District is a down—faulted appendage of the Marquette Synclinorium, being on the south limb of that westward plunging, asymmetrical trough. The dominant strike of the formations is N70°W; the dips range from 30 to 70 degrees north. Superimposed upon this trend are numerous secondary strikes and dips due to both primary deposition and to later folding and faulting. At one location along the southern edge of the New Richmond Mine the iron formation appears to-be dipping southward. Again in the northern portion of section 2? a minor fold exposes the Negaunee and Ajibik dipping southward. The dominant structural feature, the Volunteer Fault, is not a single fault as reported by previous workers, but rather a fault system with parallel secondary faults extending northward and probably .southward. A series of these secondary faults can be seen ascending in step-like fashion past the north section lines of 27 and 28. Branching off from many of these E-w striking faults are a series of high angle faults striking Nw-SE. There may also be faults parallel to the E-w faults extending south at least to the Palmer Complex. Indeed, at the Moore Mine there is a fault that parallels the Volunteer Fault for a while then strikes SE through section~34. 'Lamey (19) describes several contacts of the Palmer and Huronian rocks as fault scarps which are parallel to the Volunteer. Finally, a N-S vertical fault is well exposed in the east-central portion of section 28 where it cuts through a massive quartzite outcrOp resulting in a horizontal displacement of approximately 300 feet. One- half mile directly north an identical N-S vertical fault results in a horieontal displacement of approximately 180 feet. Three joint sets are found at the Moore Mine: N35°E, 3703; N350E, 780E: and N90w, 500W. These joints are most prevalent in the large elastic bodies and appear to terminate at their boundaries. Figure 2 is a point diagram of the normals to 300 joints associated with elastic lens #2 at the Moore Mine: each point represents 3 joints. Plotted on the same diagram are prominent structural features observed in the area. It can be seen that the joints form a well defined girdle essentially perpendicular to the strike of the iron formation, the ’Hoore Fault, and the Volunteer Fault. 18 'ISABELLA DIKE NW BRANCHING FAULTS N's FAULTS MOORE FAULT VOLUNTEEa FAULT CHLORITE ' owe a LONG'S. JOINT PLANES Figure 2. Point Diagram of 300 Joints from Lens #2, Moore Mine with Regional Structural Features 3!.29'3rimposed 19 F. Stratigranhy The stratigraphic column for the Marquette District modified from U.S.G.S. Monograph #52 (l) is presented in table I. The formations delineated in the present study are presented in table II. Detailed megascopic and microscopic descriptions of the general lithologies are presented in U.S.G.S. Monograph #28 (2). Outcrops were identified in the field using standard field tech- niques. In general, few problems were encountered in delineating the different formations with the exception of the quartzites. Identifi- cation of the three quartzites presents an exceedingly difficult pro- . blem, one which is limited not only to the study area but common to the entire Marquette District. The problem is this: given any parti- cular quartzite, whether it be an outcrop observed in the field, a hand specimen, or a thin section studied in the laboratory there are few techniques to apply which would enable one to sufficiently determine whether that quartzite is Xesnard, Ajibik, or Goodrich. Since from a ‘ lithological standpoint the three quartzites are alike, other methods had to be relied upon in the field, including such criteria as stratie graphic position, structural interpretation, observable topographical trends, and reliance on previous work. In general the Hesnard was differentiated from the Goodrich by arbitrarily using the Volunteer Fault as a cutoff point; i.e.: quartzites below (south of) the fault are termed Goodrich, quartzites above (north of) the fault are termed Hesnard. The Ajibik is differentiated from the Mesnard and Goodrich using inferred stratigraphic position. Detailed criteria are presented below for specific exposures observed. 20 Table I STRATIGRAPHIC COLUMN OF THE MABQUETTE DISTRICT* Pleistocene Glacial Till UNCONFORMITY Cambrian Upper Cambrian Sandstone UNCONFORMITY Keweenawan Olivine Diabase Dikes UNCONFORHITY Killarney . Acidic Granites ' UNCONFORI-ZITY Upper Huronian Upper Michigamme Slate Bijiki Iron Formation Lower Michigamme Slate Clarksburg Volcanics Greenwood Iron Formation Goodritn Quartzite UN C011 FORE-IITY ’ _ Middle Huronian Negaunee Iron Formation Siamo Slate Ajibik Quartzite i UNCONFORMITY Lower Huronian Wewe Slate Kona Dolomite Mesnard Quartzite UNCONFORMITY Algoman Granites and Syenites UNCONF'ORI'IITY Laurentian Palmer Complex ‘ UNGONFORMITY Keewatin Kitchi Schist Mona Schist 3hgdified from U.S.G.S. Monograph #52, ref. 1. " 21 Table 11 OF THE re a .---.........- ------ UNCONFORMITY UNCONFORMITY STRATIGRAPHIC COLUMN PALMER DISTRICT Glacial Till Olivine Diabase and Diabase Goodrich Quartzite Negaunee Iron Formation Ajibik Quartzite (Granite) Kona Dolomite Mesnard Quartzite Palmer Complex Emeta-igneous) meta-sedimentary) Hornblende Schist Granite Gneiss 22 Following is presented a field description of the lithological units mapped alongcwith distribution and correlation with other neighboring areas. The reader is referred to the Regional Geologic Map, Map I located in the map pocket. The Archean Gneiss, the granite, and the diabase and hornblende schist dikes were not studied by the author; their descriptions are abstracted from Long‘s unpublished master's thesis (28). ARCHEAN GNEISS A group of highly deformed and banded schists and gneisses have been studied just north of Lake Gribben (section 34) by Long (28) and Sahakian (27). They are thought to have been originally sediments or eruptives which were subjected to fluid envasion and intense meta- morphism. More recently, granitic intrusions have transformed them into younger injection gneisses. PALMER COMPLEX The Palmer Complex is a term used by the author to indicate that portion of the Southern Complex which lies immediately below the Huronian formations and to include part or all of the Palmer Gneiss. This rock type occupies a very indistinct belt between the sediments and the main granitic body to the south, extending for at least a quarter-of-a—mile south of the Huronian sediments. This horizon has been the focal point for continuous debate ever since first studied in 1895 by Van Hise and Bayley (2). Due to the complexity of the pnroblem, the Palmer was mapped as an entire unit aside from the several pockets of Huronian sediments to be discussed. 23 MESNARD QUARTZITE The Mesnard quartzite is found along the northern one—quarter of sections 27 and 28 where it appears as a massive, vitreous vquartzite with colors ranging from white in the east to dark grey in the west and superimposed with varying degrees of ferruginous staining. The formation is exposed in a series of northwardly ascending fault blocks, where the beds strike essentially east-west and dip 20 to 30 degrees north. Along the fault-faces are found fault breccias and hydrothermal quartz veins. Some of these quartz veins are up to five feet thick and contain quantities of micaceous hematite. In some of the higher quartzite blocks a clean, well-rounded quartzite I conglomerate is found, which eculd be interpreted as being either an interformational conglomerate or the basal Ajibik. The latter hypothesis is favored since similar conglomerates are fourd in sections 33 and 35 described below. In a few isolated areas north of the main fault, in section 28, outcrops of ferruginous slate were found. I Rosenberger (29), during the 1960 field season, studied sections 'I 22 and 23 in the Palmer District; he found eroded granite and granite gneiss hills partially overlain by Hesnard Quartzite. Ajibik and Kona L formations were also identified. The Mesnard was divided into three units: a slate, a slate conglomerate containing granite and gneiss cobbles, and a massive quartzite. A slate conglomerate similar to his was found in the northwest corner of section 27. Further east, a large exposure of strongly foliated slate was found conformable to the Hesnard. The stratigraphic relationship is not very clear due to considerable faulting in the area. If the slates are older than the quartzite, they probably correlate with Rosenberger's slates. How- ever, if they are younger than the quartzite, they could be equivalent to the purple slates of the upper Mesnard formation. Two other important occurences of Mesnard Quartzite were deline- ated. In the northwest corner of section 35 the author investigated a hill of quartzite protruding above the local sand plain. There is evidence of the existence of two different quartzites: one, a grey massive variety Occupying the northern portion of the hill; the other, a clean massive variety occupying the southern portion of the hill. In one location the younger quartzite is seen as a convlomerate sheet lying immediately on the lower quartzite. Since the Negaunec Iron Formation lies to the north, the younger or northern quartzite must hm‘Ajibik and the southern quartzite, the Mesnard. Lamey (19) studied the same ridge and reached the same conclusion. It is interesting to note that directly across the Marquette Syncline an identical relation- ship was reported by Seaman (l) in the Teal Lake Area. Tyler and Twenhofel (23) reported no unconformable relationship; but during the summer of 1961 an M.S.U. field crew remapped the Teal Lake Area using a telescopic alidade and found that the Ajibik does indeed abut against the Mesnard with a conglomerate in between, thus substantiating the unconformable relationship. Another location of importance is found in the northern portion of sections 33 and 3h. The following sequence of lithologies is found beginning with the Negaunee and going south (older rocks). The Negaunee extends south of section 28 for about 200 feet; for the next 25 200 feet, a grey massive quartzite with a good basal conglomerate is found. Immediately south of this is a valley devoid of outcr0ps. Further south there rises a large east-west trending hill c0mposed of green slaty material, while still further south another quartzite much cleaner than the first is found. Stratigraphic relationships suggest that this lower quartzite is older than the Ajibik. Three interpre— tations are possible; one, that the quartzite is not a quartzite but, in fact. a fine-grained, highly silicaeous granite; two, the rock represents a pre-Archean quartzite; and three, the quartzite is part of the Mesnard formation. Laney (18) has found that many fine-grained samples of the Palmer Complex, when examined under the microscope, were. in fact, quartzites and vice versa. Therefore, although these outcrOps have every appearance of being quartzites, one cannot dismiss the first possibility without detailed microsc0pic work. In support of the second possibility, Marsden (2h) has indicated he believes that there are some pre-Huronian sediments in the Marquette Syncline. This has never been substantiated although some of the sediments between the Nesnard and I - the Creenstones north of Mud Lake in the Marquette Syncline may well be of this age. - l The author cannot understand why previous workers, Lamey excluded, have failed to identify the Mesnard as extending along the southern edge of the Palmer District; especially since the same workers have rec0g- nized the Hesnard as occupying the area immediately north of the Volunteer Fault, a distance of only one mile. Sedimentary distribution would suggest occurrence of the Mesnand along the southern border of the Palmer District. In addition, the Mesnard is found on the northern border of the Marquette Syncline, a full two miles further west than the area in question, while scattered exposures extend another four miles further west. Therefore, while recognizing that more work in the area is needed, the evidence seems adequate for extending the Hesnard formation west along the southern border of the Palmer District form the Mews Hills through at least section 33. KONA DOLOMITE In the northern portions of sections 33 and 3h a 65—foot high east-west trending ridge of steeply-dipping, dark-green slaty material was found which the writer believes to represent part of the Kona for— mation. Hand specimens show numerous distinct angular blotches of limonite stain inter-mixed with quartz grains and stringers of chert in a fine-grained groundmass of sericite and chlorite. A well developed foliation is evident striking 8-H and dipping 7OON. Long (28) has mapped a similar rock in the north-central portion of section 34 where it is intruded by aplitic granite. He describes it as a "brown- weathering sericitic, chloritic schist." ' A number of samples were placed in a concentrated HCl solution with l a resulting reduction in weight of 20-30%. The limonitic staining is I believed due to oxidation of ankerite crystals. Due to the general E appearance, its high carbonate content, and its stratigraphic pOSition, this formation is regarded as a slaty phase of the Kona. It should be added that Van Rise and Bayley (2) report that the Kona grades into calcareous shales southwest of Goose Lake in section 22. Rosenberger (29), studying the same area in 1961, also reports these calcareous chaise. v—vfiw— V'— 27 GRANITE An orange granite intruding the ancient gneisses and the green slate (Kona) was studied in detail by Long (28) in 1958. The granite ranges from medium to coarse—grained, but becomes aplitic where it intrudes the green slate. Prominent minerals present are quartz, potassium feldspar, plagioclase and biotite. Plagioclase is dominant over the potassium feldspar. Traces of zircon, magnetite, muscovite, chlorite, and hematite are also found. Long believes that these granites represent the tOp portion of a magmatic body intruding between Lower and Middle Huronian time. AJIBIK QUARTZITE The Ajibik Quartzite is found just south of the northern section lines of 32, 33, and 3h where it lies unconformably upon either the Palmer, Kona, or Mesnard formations. Exhibited in places is a narrow conglomeratic zone with sub-angular to rounded pebbles of vein quartz, quartzite, granite and green schist composition. Above this conglomer- atic horizon the formation appears as a typical massive, dirty quartzite., Similarly related are the outcrops in the southwest corner of sectiOn 2?, with the exception that here the quartzite overlies only the Hesnard resulting in a good basal quartzitic conglomerate. In the northeastern part of section 27 the Ajibik is found again as a southward-dipping, dirty, massive quartzite, being differentiated from the Mesnard only by color and structural relationships. The previously mentioned quartz te hill in the northwestern part of section 35 shows the Ajibik lying unconformably upon the Hesnard. Southwest of the Old Richmond Mine an interesting expOSure was .studied in some detail. Previous workers have mapped this as Ajibik v. 28 since it lies between a basal conglomerate and the hegaunee Iron Formation. The rock consists of sharply defined layers of magnetite and quartzite, each varying in thickness from l/h to 3/h of an inch. ’ A normalized modal analysis of each layer is included in table III. The quartzite bands consist of individual, well—sorted quartz grains (zeundness = 0.7, sphericity = 0.8, average long diameter = 0.65 mm) in a matrix of chert, chlorite, and some fine grains of magnetite. At least one grain of elastic chert with long diameter of 0.6 mm was found. The magnetite band is actually a chert-magnetite band con— sisting of very fine grains of chert and magnetite along with some chlorite. No elastic quartz or elastic chert grains were found in the magnetite band. SuperimpOScd on both types of bands are large, fresh, ‘ euhedral crystals of magnetite, evidently of hydrothermal origin. The demarcation between individual bands is very sharp; the quartz grains exhibit no gradation as they approach the boundary. It would be difficult to account for this lithology without sub- scribing to a primary origin for the magnetite. The writer believes ‘ that this lithology represents a gradation between the Ajibik and the Negaunee formations. s. A-.“‘ l NEGAUNEE IRON FORMATION The Negaunee Iron Formation appears as an even-bedded ferruginous r chert (interbedded layers of hematite and white chert), while locally ‘ it has been altered to jaspilite (interbedded layers of crystalline hematite and red chert). Distribution is confined mainly to the r Sc"Athern half of sections 27 and 28. The beds strike generally west- n‘xrthwest and dip between no and 70 degrees north. Locally the beds 29 Table III HODAL ANALYSES O? SELECTED SAHPLES Sample: an 66 317 318 319 321 u57-A u57-B Quartz elastic 50 50 69 #1 53 6O hydro 5 Sericite ' 56 59 Chert elastic 1 7 . 3 matrix 30 50 2b n 5 38 2!» 1:0 Hematite - 1 Magnetite 5 6 5 1 l 5 #6 6 Chlorite 5 2 6 Leucoxene 2 1 Totals 101 100 100 99 102 98 98 99 Sample: Clastic 44 floors Kine, lens #1, CQA2 Lens 66: Moore Mine, lens #6, CS 31?: New Richmond Kine, 02131 318: New Richmond Mine, Q3 319: Moore Kine, QS 321: Iew Richmond hine, CQA1 Ajibik h57-A: SW of Old Richmond Kine, Quartzite magnetite layer h57-B: SW of Old Richmond Kine, elastic layer 30 exhibit numero's fluctuations due to minor folding and faulting. Extensive zones of brecciation occur throughout the formation. Interbedded within the iron formation are numerous elastic deposits, the study of which forms the principal portion of this thesis. Economically the iron formation is poor due to its high silica content. There are no mining Operations currently active although in recent years small tonnage has been shipped from the New Richmond Kine for use in blast furnace cleaning. Recently, extensive mining and concentration has been initiated west of Palmer. A more detailed description of the iron formation at the Moore Kine is presented in Section III. PYROCLASTIC HORIZON Striking approximately N700N from the point where the railroad track crosses the 28—29 section line to just east of the floors Eine is a highly conspicuous pyroclastic horizon. This horizon is located ECO feet above the base of the Negaunee Iron Formation and consists mainly of an agglomerate and a lithic tuff. This occurrence is described in }.Jo greater deta l in Se tion III. 0 GOODRICH QUARTZITE The Goodrich Quartzite is restricted to the center of section 28 and to a small arm protruding into the north—central portion of section 32. An excellent exposure of basal conglomerate can be seen 1r section F ’J 28 just north of county road 3.8. and west of the railroad cross n 0’4 Here subangular to rounded pebbles and cobbles of ferruginous chert, 2’. y). jaspilite, chert, vein quartz, and quartzite are imbedded in a matr f quartzite and sericite. Simila 1r basal conglomirates are found in section 32 with the addition of granite and granite gneiss cobbles. Above the conglomerate the formation grades into a typical messi e, te stain. Two Ho rey-white quartzite with varying degrees of hem t distinct areas of outcrOp are found in section 28s eparated oy a quarter-mile of swamp. ho bedding planes were found, but all observed outcrOps trended in an E-W direction. In the west the out bcrOPS are small, in the east they are dominated by a massive quartzite ridge. T.e isolation of thisr ridge, its parallelism with the Volunteer Fault (only uoo feet north), and its likeness to the other uartzites poses a question as t whether it is actually Goodrich. Detailed study is needed to answer this question. F0 or the purpos of this report, the author chooses to follow the criteria established earlier and continue to designate this as Goodrich. INTRUSIVZS Five dikes of consequence and a possible sill were mapped during this study. A larre dike known as the Isabella Dilw e, several tens of eet wide, was observed at the north--:est corner of section 32. Mengle (26) maps this di ke fro om the middle of section 31 ac mo 5 the corner of 32 to the middle of section 29. about 1 1/2 miles. The Isabella Dike exhibits typical olivine diabase texture and compos 1 ion. It is probably older than the olivine diabase dites of Keweenawan age, being some- what altered. Further, t does not possess the negative polarity characteristic of most Ke ewee nawan dikes. A somewhat similar rock type cut ing the granite in section 3% he; been describe' by Long (28) as a "fine grained, brown weatherinr, black diabase." It would appear that if tnis is a dike, its width mu ust no in excess of 1'0 feet. Sau“1es were found to contain mostly serpentine and plagioclase, some epidote, chlorite, and muscovit e; but no quarts or magnetite. The rock has undergone extens 've alteration (the original olivine, if ever present, is completely absent) along with major deformation as evidence by the high number of strain lamellie V The age re latm.on nip to the lszibella Dike is in question, bit with tne r-a-J present information it is considers: older. A typical diorite dike, thoroughly sheared and chloriti zed, cuts east-wes throurh the iron foriation on the south side of the New Richmond Mine. The dike is a few feet w H. CL ('3 p.) 2.3 r u 9 -n be easily traced a distance of one-half mile ; the dike is lost at either end of the clearing. A twenty foot wide dark reen to blaek, schistose, hornblende, CQ bioti te dike is reported in ection 3n by Long (23). He states that U) Q) :3 F“ (‘f‘ .1) a structurally it no t—dates the Archean gneiss and predates the gr & A light colored, highly weathered dike visible at the Foor Mine §) bed in Se i311 III. P. entrance is descr Just off the southwest c orne r of the Old Richmond Mine there is large OitcrOp of a dart:- green, chloritic body thought to be a sill. it appears to be conformable to the surroundin giron formation while 9.) faint colur as r structure is in evidence. * was not possible to trace C this outcrop laterally. 33 CLASTIC- IRON eon 1110 a 11m101":*:3 AT T113 nocne n A. General The Moore Mine is located in the south-central portion of section 28, TU7N, R26‘I, Upper Peninsula of Michigan, and approximately two miles east of Palmer, Nichigan (see fig. 1). Access to the area is east from Palmer via paved County Road NB; the last eighth of a mile being south along a well established trail to the mine site. The mine is located on the hilly terrain south of and overlooking the swampy central portion of section 28. Ceologically, the mine is locatei within the Negaunee Iron Formation at a pos i ion approxima.te1y 150 feet stratigraphically above the base of deposition. Locally, the Negaunee consists of alternating layers of chert and hematite striking between N55°J and N “5°! and dipping betw ween NOON and 7OON. A thick pyroclastic horizon is present within the iron formation 400 feet above its base immediately below which the iron formation has been altered to jaspilite. Parallel to and some 40 feet below the pyroclastic horizon, at the entrance to the Moore Nine, is the Moore Fault striking N65°N and dipping U-SO‘I to 750N. Fluids moving up and along this fault probably account for the jaspilitic zone, wit the pyro- elastic horizon act in3 as a stratm aphic barr ie er. A superdip survey traced this jaspiliti c zone at least #00 feet further east. The Noore F&51t can be further traced along a series f bluffs in section 33, mile east, where it now is strfl ting NSEON. 3’; Within the iron formation there are unusually large quantities of clastics concentrated as lenses, be s, flood plains, channel cuts, and as isolated pebbles, cobbles, and boulders. A total of 42 elastic bodies were mapped during field work a the Moore Mine. The composi- tion of these elastic elements consist primarily of quartz and chert fragments in a matrix of chert, sericite, hematite, and biotiteJ chlorite with minor amounts of magnetite, leucoxene, and zoisite. The area has been cleared of overburden for a distance of over a quarter of a mile parallel to and some 250 feet perpendicular to the strike, thereby exposing in cro s-seetional view over 330,000 U) square feet of iron formation and associated elasties. Within this area are numerous mining cuts both parallel and perpendicular to the bedding, providing Opportunity for a comprehensive study of iron formation—elastic relationships. The Moore Fault is exposed as a series of branching faults approximately parallel to the Volunteer Fault. From Richard's Cut (see Map II) westward the fault cuts across the iron formation at low annles. It can be traced cutting the tOp of several upper lenses, but is lost near the middle of the stripped area. The fault is an important factor in controlling the shape of these upper lenses. The vertical (displacement is estimated to be at least 30 feet. Although a horizon- taJ.displacement of only a few inches has been observed, the true (iisplaeement may be significantly greater. Another small but well eXposed fault occurs in the far western pxxrtion of the mine cu ting through a small elastic lens. The fault 35 °trikes N79OE and dips 880M. The horizontal displacement exhibited by the elastic lens is 9 feet. Three sets of joints are found at the hoore Nine: N3503, 3708.; N3SOE, 7 ”OS and NQOL, 500W. Those joint are prevalent in the U) large elastic bodies and appear to terminate at their upper and lower boundaries: only a few joints can be traced on into the iron forma- tion. On the other hand most 'oints traceable in the iron forma- I tion follow on into the elastic bodies. A point diagram of the normals to 300 joints associated with lens ,2 at the be re Kine is presented in figure 2. It can be seen that the normals 01m a tight girdle acre: 5 the net and that th es ejoints are es ntially perpen- dicular to the strikes of the iron formation, the Moore Fault, and the bianching faults north of the Volunteer Fault. B. lb apping Procedure Mapping was accompl 18 he using a telesCOpic alidade ard plane table at a scale of one inch equal to ten feet. Vertical control was obtained by level shooting from an established elevation point at the crossing of the Chicago andI orthwestern Railr01td and County Road KB. The Palmer Quadrangle 7.5 Minute Series TOpOgraphic Nap of 1952 gives an elevation of 1,313 feet at this crossing. This-eleva- tion was carried 0.35 mile,using es abl'shed forest “h ing and back- sighting procedures, to a second order base station. From this station a network of #2 instrument stations covering the study area was stablished. Sachs sta tie on was perzanen,ly ma rk ed for reoccupation. After the traverse was clos ed detailed mapping from each of the (.9 n. u the first being of‘a general nature to outline the strippcl area and the numerous mining cuts, to locate iron foen«+icn—pvio las tic con- tacts, and to establish elevation control Ov er the area. The second phase consisted of a detailed survey of the elast ie bodies. Outlines of the clas tie bodies were mapped at intervals of no greater than three feet, while mini 1n3 cuts, stripped borders, etc., were mapped at intervals of five to ten feet. Vertical control was established for each of these points using a standard surveyor's rod. Horizontal neasurerents were made with a lOO-foot steel pe. E].evation contour lin were drawn in the field with a contour inter al of ten feet. Clasti lenses with several layers of the surrounding iron formation were also sketched in the field. whenever a map sheet was changed a minimum of three control points were used for reorientation. hap II (in the map pocket) is a COpy of the field map. C. Sample Collection and P-e aration ('1 During the detailed study of the Moore Mine area, #27 samples '6 were collected from the iron orw ation and elastic bodies for laboratory study. Some of these were collected as representative or their particular lith0103y; some were gather ed rando.w:1w throughout the study area; while others were collected at definite intervals along a particular traverse. In addition, 23 elastic samples were collected from the New Richmond Kine. All samples were accurately located using telesconie alidade and plane table or steel tape. Each sxnple t( prepared as a seni-polisned section using standard proced r s of diamond saw cutting and lappin 3 . Lapping was carried down through the #00 ca de corundun powder, providing a surface when 3 L) 37 wet adequate for binocular study. All polished surfaces were de-stainel to remove the pr ev alia .t hematitic stain, see Appendix A,e xperm nt 2 for detail 0’) D. Sample Anal‘ses l. Micros00pic Analysis Petr03raphic Initially each polished de-stained specimen was briefly examined under a binocular microsCOpe and placed in broad lith0103ical J (‘f‘ . 1ve (D groups. Forty-three thin sections w re prepared :rom represente samples for petrogrc aphic analys its . It was found, however, that such a study was imp'acti ca 1 due to intense hematitic stainimi . An attempt to de-stain the thin sections was not successful. Since only a few mineral species were present, all of which could be it eri flied in polished section once in i' ally identified in thin section, petr0"“".iic methods were used primarily to identify specific minerals and to per- form modal analyses on selected specimens. hodal analyses were per- formed with a si —barrel in e3ra in3* stage using ten traverses per section; results are presented in table III. In addi ion, a su1te of some 70 thin sections covering the Palmer elastic horizon was graciously lent to the author by J.?. Ler 3le (Uiscon sin State University) providin3 the chance for study of the iron formation- clastic relationships in the entire area. Binocular 7" AL $.10 The binocular microsc0pe was the principal tool used studyin3 and classifying the samples. A detailed analysis of each Q "J‘ ‘ I" 1 5!- Q r :4 - te.«tural, s 31u3n1ral, 1.1.:-o- -. . ~ 4 O '- ‘v. ' . q |. not.“ -‘ ‘ ‘ 1cal and m1n.ri1031Cal relationships. All samples, es pe c1 lly tne 38 iron formation samples, were examined for elastic chert; only minor quantities were found. A six-barrel integratin; stage was adapted to the binocular microsecpe and used in determinin of quartz grains per sample and to measure thicknesses of hematite and chert bands for selected ferru3inous cher samples. Petrofabrie A standard petrofabrie analysis was performed on the c-axis orientation of quartz grains in a eherty quartzite sample from the New Richmond Mine. A maximum c—axis orientation of 6% was measured; D but no clearly defined symmetry 01 fabric was een. While use (I) O QClmcfi U) ’U was not orientated in the field and thus no conclusions can be made Q petrofabric analysis may be worthwhile in study1n3 the post-depositional history of the iron formation. 2. Sieve Analysis ne study of some ('0- A new technique was develOped to facilitate of the elastic samples. Using a concentrated hydrochloric acid solution to dissolve the hematite followed by a boiling solution of ‘3’ H (9 b) y). g. ). potassium hydroxide to dissolve the chert due of "cleaned" sen grains were obtained. These sand grains were then studied by normal procedures of Sieve analysis with conclusions applied to tne elastic must be resolved. That is, to what extent have the sand grains been ‘ Y‘fi k A. - '2 ~ *2 '. I‘ ' 'F‘.‘\ '3' ‘ J ' r J" ‘ P‘H 4" .va‘ . ‘5‘ altered since nepOsltlon anl to what erred- does the aamellflb a 39 involves the effect of diagene tie and metamor Operation since deposition and is a problem basic to the anal of many sedimentary roe ks. For this study it is tacitly assumed th.t ny such alteration of the sand grains was minor ani would result in an error less than those errors inherent in the nechanieal sieving Operation itself. The second question involves errors intrcduced by mecle nieal breaking of grains during the field sampling and la boratory prepa- ration. ln removing a sample from an outerOp or when preparing a sample ford is Q5resation, a tinite number of grains are broken. tion. For the case where a sample is broken with a hammer, jaw crusher or similar mechanism tr ere is no way to easily determine the number of effected grains. To reduce damage, larre fin d sarpl es were taken from "nieh small laboratory specimens were prepared. Dv cu ting the sample at" V. a controlled surface area is formed and the percenta e of brolcen "rains ( 3 {D .J \+ k 9 CI" (‘3 (D U) s P g .10 :3 Q) <+ 0) L C To minimise this pcrcenta e of broken gain one must look for a spec r‘imen having the smallest surface area for a given volume, for practical labora' we y wor Hi this is a cube. Us in5 a simplified cubic mcicl where the .and grains are spherical and are arranged in a homogeious manner one has only to eom_are the shell volume to the total volume in orier to estimate the maximum per- centage of the sample disturbed. The followins relationship expresses percent disturbed volume (”d) as a function of cube dimension (n) and grain diameter'(8). M) Vd = shell volune : n3 - (n~2§)3 total.volum3 n3 Using tne median grain size, the percent disturbed volume for each disa55re5ated sample was computed and is listed in table IV. The third and most important question was resolved by extensive laboratory testing showing that sand grains after bein5 subjected to the develOpedd Mica 55re ation procedures were not measurably changed in any of the four para .eters Observed, size, saape, roundness, and “3' Ho 3 ('3 surface texture. These expe. nte, including the develOped disag- gregation procedures, are documentcdi ndetail in Appendix A. Standard sieve analyses were run on six samples (’h5, #61, #l7h, #183, #303, and #322). Cubic specimens measuring between one and two inches on a side were cut fro.n the oinal Field sample usin standard diamond saw. Each specimen was dissa55recated and sieved accordin5 to the procedures outlined in Appendix A. Tne specimens appro oximatei tne mathematical model to a high degree; the sand 5raim sphericity avera5ed 0.80, and the samples were quite homo throughout. Statistical measures are generally used by 5e0105ists to con- veniently express certain Characteristics of a frequency distribution in a concise mathematical manner. Table IV cont ins a number of statistics for each of the sieved samples. This data is presented for the dual purpose of possible correlation with previously pub- lisned sedimentary data and for comparison and evaluation betwe een the U) ample s themselves. In onier to evaluate such data and to draw reliaole conclusions ne must be familiar with the fundamentals of #1 Hm.0 N0.H 00.0 m0.o mH.0 as.fl NH.0 om.o no.0 om.0 mm.0 o.m m.H Nam om.o mo.a 30.0 H0.o HH.0 H2.H mH.0 mm.o 02.0 sm.o om.0 o.s o.m mom sm.o oo.H HH.0 no.0 om.o sm.fi 00.0 no.0 so.0 33.0 No.0 o.e o.ma mas sm.o H0.H no.0 H0.o 0H.o om.fl Na.o mm.o :m.0 om.0 Hm.o 0.: N.0 sea mo.o mo.o 00.0 00.0 om.o Ho.H 02.0 ms.o No.0 no.0 No.0 s.s m.ma Ho 0N.o s0.H no.0 Ho.o 0H.0 om.H oa.o wm.o No.0 om.o om.0 o.m m.m we see mam mam mm m om «00 oz oz we as he Aoov Homage es s aflosem moHuhHHSum mhmMASQ magnm >H GHDNH. ’42 statistics and what they actually measure in 5e0105ical terms. The reader is referred to Krumbine and Pettijohn (30), to Krumbine (31) and to Pettijohn (32) for a thorough treatment of this subject. Figures 3 and a present hist05rams and cumlative curves of the size distributions. Samples #45 and #17U are from lens #1, a well defined, ideally smtped lens at the hoore Nine. am les #302 and #322 are from a well def H0 .ned set of beds at the New Richmond Mine (see Section IV - Location 15) imile samples #61 and #183 are from lens #B-h, a poorly defined zone of high sand concentration at the Moore Hi.e. The size distributions tend to be similar for samples f"om the same deposit: but dissimilar for samples from different deposits. This would i J- - I L ‘, «'4- SUSSeSb that each f the ochsivs H epresent a singular event each governed L. (11033. i»... by a particular set of source, transport or depositional ccnd Comparison of the size distribution plot to examples from Pettijohn (32) U) gree of sorting and lack of clays would indicrte that the sands analysed represent well woraed beach sands. In going from lens #1 to the New Richmond beds to lens #3—h there is If the same source is postulated for each deposit than these ditderences can be.ascribed to differences in transport or deposition meczanisms. ‘1‘: “"37". m - . .0 m' - .3 .- b L' .. ,‘ - thw 0~~ echanism. Lao “on" a“ 9: O cor.;n5 '1 larper me-" 43 '00 45 8°: 45 ; I74 C a _ I74 ,.. f” 60-— I— .. $40[ [I— : zo—I— - - I— o' L. _ —]—-. h L. :iglOKJI- _- _ 25()25 m80_ 303 .. 322 .. 8‘ m I. _. p - 322 o‘so- - - l£40» ‘_*"‘" - "' - .-—-"' 0 .. -~ I- -20— — ‘ - m s 0:. "I J— :- L IOO- .. L 6| 80.. 6| _ l8?) _ a, .. .. - IBB SO; " ' 4.0— -‘F". :—_ L—- :" .. 20- - - 0.. "T'L - '- FL: - —l—I_. 2 l l/2 V4 V8 ma V32 2 I l/2l/4l/8l/16l/32 2 I In I/4I/a VIsI/az GRAIN DIAMETE R (mm) Figure 3. Size Distribution Hist05rans of Sieved Samples NNM .vt mafiaemm o¢>msm no mcofiospfiupmso mudm o>damfiseso .AEEV 9 .l 0 O NNm immim .m .vtfiQv m _ imposes mm._.ms_<_o 2.4mm . WWI-u..n-nlv _ _ qua-u: eta me NNm m mom e mom ooossoE 52 m..mv.d mcou mums mHQdB ,nd $.10 .1. ‘. Ln.) 1‘.) Chert ovals are usually outlined by titaniferous magnetite alteration proiucts of hematite and leucoxene while lying in a ground- mass of minute sericite cr"stals. Tne serieite eiystals are typically blade-shaped with their long nitude as the chert mosaic. The outlining magnetite is of hydrothe ma origin although there are iso 1 wt d, slightly worn crystals with'average dimensions of 0.03 mm x 0.01 mm. Host of th of altering to hr “tit . Some of the leucoxene f-a (U typical elastic earance and are probaoly either prime ry clastics or less likely complete alteration products of maenetite. It is signifi- cant to note that there are no instances where mtrnetite crystals are observed in the process of altering to leucoxene, either the cryst tals are magnetite o H leueoxene. Hydwroihe rial quartz appears in randomly dist ributel blotches thrOLI-hout the samples 0 is superimposei upon the entire rock. In most samples the chert granules are orientated with their long axis parallel to the long axis of the lenses in which they occur, which is also paralll to the striPe of the iron fornation. This - couplei with the oval shape presents a textural appearance very (I) p.» E! P. H n: '1 r +- O the pillow lavas of the Hm hern targuette District. The author 13 not sugges tin : that the similarity of appearance is in any wa ay indicative of a similarity in origin, they are Without doubt elastic. Rather the texture of the rock suavests that blob U) of chert were deposited inli vilually one on tOp of the other, each being viscous enough when deposited to support the newly iepositei oval with minirun resultant def ornation. 54 Cherty Quartzite (Oil) The cherty quartzi+e (CQ) are found abundantly throughout the elastic horizon in the Hoore Kine. This group, consisting primarily of chert, quartz, and varying percentages of hematite, is readily divided into two sub-groups one of which contains three cla ass es. These four distinct litholOgies, designatel Cint CQAZv VQAB, and sQB, are listed with their eonpos itions tabulated below; all are conformable with or grade into the iron formation: Cle CQAZ uQA3 CQB Quartz elastic- - 611-60 33-60 24-60 65-75 Chert matrix - - - ~35-55 30-55 35-55 20-30 Hematite Naenetite - - — - - — - - l- l—7 1- 1-2 0 Chloritc- - - - - - - — - 0 O 0 2-7 For the CQA's, the quarts present is primarily elastic sand grains of the clear var rie ty along with a fe" isolated fragments of milky quarts; no hydrotherral quart: has been founl in any of th sanples ohservei. Clastic grains range from 0.12 to 1.30 mm in size, the a» era; ebeing 0.50 an. Average neasurei reundness and spherlcity of these grains is 0.05 and 0.80, respectively. Die to the ettensive amoun of hematite, hand speeihens apizar to exhibit sand grains that are corro:ed. In deshainee polishei sections the grains are found not to be corroded but rather to he "flea ins" in a matrix of hematite and chert. There is no ireferrei shape orie tation ohservable; one sample fren the You Richrond Kine, however, did have a 5% naxinnn C-a"is orientation. Finally, most grainss show the typical urdula ory extinction of .etanorphizei quartz. A few angular quartz fragments obserVei have average dimensions 01 0.57 X 2.19 mm. All gradations of elastic chert are found from fragments down to granules. The average siz f the fra Lents is 3.08 x 1.41 mm; the granules range between 0.80 and 0.50 mm in lon3est diameter. Shape of the granules are either oval or spherical all with near T‘ perfect roundness. 0.07 mm independent of whether they are constitue L3 (4- 0) O "b ( f' .1. d) H) l :1. 3m mnul.ets, or matr x of the Specimens. All chert exhibits extezsive undulatory strain. crystals, blotches, and dike- ihe—strin3ers :urrounii.3, but never cutting through the quartz grains. The chert gra: ules, curiou 131 , do . Q contain minute spec The 33neral appearance of the magnetite is fresh a1 tiloug h some ca" 3e seen altering to hematite and leucoxene. Hematite blankets all the 0 samples; once the staining has be;n cnonically rape" ‘ the residual henma te is found to he an integral conponent of the ma. trix. Figure (D 't H O .3 H u L) U) a: I...) O ¢9 L. p) H d- L . 6 shows a photonicrograph of a CQAns anpl a N grains in various sta es of undulation are seen floatin (mosaic) and hematite (Opaque) groundnass. 1 --. . r- . ' The CQ~ sub-rroue V&“193 slian v . - ' .v .1- w— --A -‘ H \ 1ar*er 0 - 9.00 "e Lhile the spher-ei_y and roa:rntos o; the ele~7 5_ain: are the :a e. The quert’ “reins are cached close: than the A) . yu an ,- .\." “‘"r 7.». - r. .. -_ "T "/ ..' i-‘- I. u ‘h .. -\ l -.‘ fl _ . , u. "-, y l on - x u '- - fi. ’V- w.‘ .. I. .i 56 CQA's resulting in undulatory extinction and interlockin3 texture 1th suture structures in conspicuous evidence. A3a in no p1ePerre d shape orientation is observable. Unlike the former, milky quarts is found as rounded grains up to twice the size of the clear quarts gerrins. Petrographic study indicates that these are rounded frag- rmnrts of quar site (possible Hes nard source). ' ‘The chert, magnetite, and hematite content is observed to be similar to the CQ A '5 except for the fact that magnetite is not obs erved alterin3 to leucoxene. The primary difference noticed between the two sub- -31 cups is the presence of chlor its in the CQB'S. Chlorite is seen as sheafs and plates intermixed throughout the matrix, it is light bro 11 to or 13~ht green to dark brown, has a biaxial negative Optical character and is slightly pleoehlorie. The above properties would indicate thurin 3i e sixilar to that discussed by James (3Q). A typical occurrence of a C03 elastic is shown in figum 08, conta inin interbe-s of chert (light), hematite (dark) and 003. ess the same gene? ml charac- U: Uhile»each of the four litholOgiesjpcs teris tics;++mw'd.iffer from each other in one or more specifics. For instance: only CQB contains chlorite, only CQA2 shows evidence of Significarfl; primary hematite, while only CQA1 and C0 B contain sisnifi- ‘- o t ‘ cant amcnlnts of elastic cnert. CQA Similar to CQAi' except for the 31 at. D ‘ o o 1 I V 0 lavx 0* «enert and closer ‘acking. F13ure 7 snows tne close paexing of tee C“A lithology. Further each of the sub-3r0ups seen to be restricted é?inite geographical locafi on; CQ_1 and CQB are located at the , - extent of the New Richmond Mine; 0 and CQ .L “'1": “7 r" a," o .. .° 1' J. -. 1... --1° 1 'i LOOrc nine uhe iolner 1n the eastern and central Olulon tne latter : ‘ x. 3 in a Chert ‘ ‘7 I .V. 10013, 10X . Photonicr A Ed .1: “'3 sand grains L .u ) aroundnass, H- r, . 'n‘ - :13ur2 r. CQAB Semi—polished Close Packing of San: Grains, "L A c r"- ' ..-‘ .. ;,chel sur.ace SCOHLF in the western portion (one srm ll CQ lens ##1 is found in the far western extremity of the Moore Mine). Finally, each of the l the- ',.Jo logies are founi in a pa artieu la 1r physical setting. At the Xew Richmond Mine CQA1 and CQB are in te rbedded with the iron for nation, most beds being Only a few inches thick. The CQA2 t-ype is typically found as long, narrow, perfectly formed lens es: while the lateral edges of the CQA3 grade by "on-lap off-lap" into the i10n formation. Serieitic Quart site (Q8) The serieitic quartsites (Q3) are composed pr1rily of quartz l) grains in a serieite matrix with minor amounts of magnetite, hematite, and elastic leucoxene all in various degrees of alteration by hydro- thei nel uar ssolutions. The range from san 1e to sample and from P - lens to lens is hi3h. A typical seni-polishei specimen is shown in figure 9. Note the apparent lineation and corrosion of the quartz grains. This group could probably be subdivided into several sub- groups with more detailed study. A tabular composite is presented below: Quartz elastic - - - - - - - - - - - - - hydrothermal- - - - - - - - — — - Serieite- - - - - - - - — - - — _ - - _ _ - Chert Ill \JHN i’fi’fi’ O\\A)\n oom matrix— ' O 3 Hematite— - - - - g - - - — — - - - - - - - - 1_n 0 3 O l Nagnetite ~ - - — - - - - - - - ~ - - - - - - Leueoxene - - — - - - - - - - - - - - - - - _ The elastic quartz grains differ from similar grains in the other 3r011ps in bein3 oval in shape with average rouniness and Sphe ric ity of O. 639 a.7.d O. 50, res peetivel'. Grains ranse between 59 Fig*re ‘. CQ3 Semi—polished Specimen Sh wing Interbeds of Chert (1'3Et) Hematite (dark) and Sand Grains in a Chloritic Cherty Matrix, 2X 51":2 ;. j; i;:i-polished Specimen Snowing Apparent Lineation and user 51 n of the Quartz Grains, 2X 60 0.20 and 0.68 mm in size with 0.45 as the average. 'Eiydrothem al Ho *3 solutions have cut throug'nout :1e speeimens significantly alter the granular texture. [any instances are observed where solutions have extensively corroded grains. All elastic quartz grains show strong undulatory extinction and interlocking textvres. In places the grains are highly fractured and filled with hydrothermal quarts, ma netite, hematite, and even serieite. Only in a few instances can rectangular sheafs. Occasionally a few small grains of chert can be identified. In the vicinity of the hydrothermal veins tiere is a noticeable enlargement of the s ericite v ains. Magne tits is observed as long stringers 'r:ir‘;din~'T around the elastic quarts grains and bein Another form of magnetite is in evidence, that of rounded and semi- |-Io :3 2': a d ‘0 i .10 f3 0) U) ,3‘ O :: :3 O U) H. would indicate a elastic or Hematite, a ide from the usual stain, is visible as an alteration product of the hydrothermal magnetite; no prina_y hematite is present. Leueoxene *~ains are found abundantly thrauv. 0-- emi-rour ded rectangles avera definite shaYe orientation with the long ax's ? the rrain.s parallel 61 Cherty Sericitic Quartzite (CQS) The dominant clastics, by volume, at the Moore Mine are the cherty serioitic quartzites (cos). This group is readily divided into four sub-groups described below. (Casi) The most prominent of the CQS sub-groups is the cherty serieitic quartzite conglomerates (CQSA) consisting of various sized fragments of chert, quartzite, serieite. iron formation and Q8 ran- domly deposited in a fine grained matrix of chert and serieite. Due to the nature of this sediment there is a large variance from sample to sample. Figures 10 and 11 show two typical textures for the CQSA lithOIOgy. No attempt was made to subdivide this sub-group. A table of the range in composition is presented below: Quartz . (218.8th ------------ 5.40 fragment ----------- 0-25 hydrothermal --------- 0-20 Chert elastic ------------ 0-27 fragment ----------- 0-25 matrix ------------ 20-65 Sericite fragment- ----------- 0-25 matrix ------------ 10-25 Magnetite ---------------- O-Q Hematite ----------------- 0-6 Leucoxene ---------------- 0-3 Quartz appears in a gradation of sizes from cobble-size down to fine sand grains. Roundness and sphericity also vary over the entire range. Hydrothermal quartz is visible as veins and blotches throughout the lenses, in places completely surrounding elastic Figure 10. ' ical C‘s Semi-polished Specimen Showins Sub-rounded u A - - o Fragments of Q), Chert and Sand Grains in a Sericitic Chert Hatrix, 2X Figure 11. Common Hear 63 fro ments. Locally the elastic fra inents reveal intensive dynamic \J action lein g,‘ strained erd ~ shed, and subsequ ently intruded by solutions of quartz an ma Chert is present primarily as a fine Frain matrix. Near the bottom of the lenses, the unclerlyins ferruginous layers of iron formation can be seen in varying sta eventually being leac died cit, the chert being reduced from coarse fragments do ctrn to small nul.es. hosto the fre gnents and graru ules contain small percentages of sand erains. Chert fragments with sub- angular shapes are found throughout the lenses, usually no larger than a square inch. Se r1 Hcit i.s also prinarily found as matrix; but there are numerous fragments with inclusions of cnert, quartz, etc. A few 1 m olated sheafs of biotite-chlorite in the early sta=es of alteration are found throughout file lenses. Magnetite is found only as Hydrothermal veins and lyc Vie! eleped crystals altering to hematite. Nei her magnetite nor her tatite give any appearance of being primary in origin. (CQSD) Composition wise, the CQSB sub-“roun is nearly identical to the C283 sub-group, the orinai difference bein and fines. In hand spec cimen this rock type has the appearance of a Quartz elastic- - - - - - — — - ~ - - -15-35 hydrothermal — - - - - - - - - ~15—5 Chert matrix - - — - — - - - - - - - -20-6O Sericite ‘ matrix — - - - - — - - - - - - —lO-25 hagnetite — - - - - - ~ - 4 - - - - - - - - O Hematite- ~ - - - - - - - - - - - ~ - - - - 0-6 0 Leucoxene - - - - - - ~ — - - - - - - - - - Quartz grains are similar to those in CQSA specimens except that they exhibit a pronounced dynamic nistor=. The chert and serieite compose the matrix and are found as fine grains and sneafs respectively. Occurrences of magnetite and hematite are also similar to those described in the previous section. The occurrence of leucoxene is slightly different from that of the CQSA subhgroup: it is observed only as an alteration product of ta This sub-group is found intimately associated with the CQSA sub- grozp while being different both from a standpoint of lithology and I I I I I I I I I I O I clastic- — - hydrothermal - - - - - - - - - - 2-50 matrix — fragment - — - — - - - - - - _ - 0-5 Sericite- - - — — - - — - - - - - - - - - -4o—8 Biotite-Chlorite- g - — - - - — - - - - - - 1- Zoisite - - - - - - - - - - - _ - - - - - - 1 Leucoxene - — — — - - - - - - - - - - — - - 2- O I I I I I I I I I I I I \A) ,1. J1 65 \"J impre nate WI with slender sheaths of leucox no (see fig . 12). There is no observable evidence that the leucoxene resulted from alteration of the magnetite; all grains are 1005 leucoxene. A few quartz grains and quartz and chert fragments are present Samples studied are soaked with hydrothermal quartz. Also, significant quantities of chloritefbio tite, perphyllite, and zoi: ite have been identified. Perphyllite appears to be concentrated along joint planes and is believed to be of hydrothermal origin. ( The CQSD sub—group has a coupositi on and texture between the ’N asp) C) CQA7 and CQSA litholo ies. This litholo 03y app? .er as a loosely packed CQyZ with minor but noticeable percenta serieite, and hydrot.re e1 quaxt' .ra~o=nts along with an eq.1ally small influx of serieite. The average cooposition of the s b-groun is pres nted belo ow: Quartz clastio- ~ - - - — — — - — - - -30-5o fragment - — - - - - — - - - _ hydrOtherfl 3.1 " -' " - D - .- I- .- I n I k I O O I N fragment - - - - - - - - - - - matrix - r - - — - - - - _ - _ 1‘) I 000 I O Seric it fragment - - ~ - - - - - - - - _ matrix - - - — - - - ~ - ~ - - -1 - 5 Magnetite - - - - e - — - - - - _ - - - - Hematite— — - - - - - - - — — - - - - — - I! H ' 00000 I O I I—‘KJKJJI‘Om UVKJ Leucoxene - ~ ~ - - - - - - — - ~ — - - - During the detailed study of the Hoore Nine, b2 elastic bodies 0 o 0 '"0H D 4" were ident1f1ed, sanplel, ad studied. 0“ the basis 0; their Semi-polis k5. nu. - ‘lC ... \) u A I. \4 {atrix, 2X in; of Assortel 67 9‘ lithological and te"tural prOpe r ies Jach lens has been cate dorisei ( .110 g ,-f :-. ’ H and placed into a litholo'ica l "roup or sub-oroup. Lenses # o s u #8, #11, #1h, #19, #30, and #38 are the type lenses for the CQAg! CQSA—CQSC, CS, CQ3,, CQSp,eohb 9, Q3 anz CQ: groups and sub—groups, respectively. Presented below is a description of each lens stulied in numerical order, see flap II for their location. Table VIII con- tains tabulated data for each lens, while table IX contains a summary of lens data by lithology. Clastic lens #1 is the type lens of the CQAZ sub-group. The dimensio..s are appr 0): inately at feet by h feet and thus a shape index of nearly 0.1. Although tne general snape is that of a double convex lens, the western portion etchibits a slightly greater width. The lower bourflary varies from 1.9 to h fe et abov lens #2. Tue exposes surface consists of crumbled material and, due to the subsequent erosion, is sli htly depre sseC below the surrounding iron fornation. The actual contact, however, can readily be obse‘m ei and is confornatle. The average compo sit ion of the lens is identical to that of the CQA2 litholOgy; the sand grains "float" in a matrix of chert and hematite. The lens exhibits gooi sorting and medium packing of the sand grains, the texture is homogen ”on Analysis of data indicates a slight increase in percenta:e of quartz grains and primary hematite from the bottom to the tOp of the lens. 0m.0 sm.0 02.0 c.mm 90.0 0.: 0.m: mmou :s «\z e z <\z 0.0 0H.0 0.0 m.e m0 ms an.0 Hw.0 02.0 m.mmus.0 m0.0 N.:fl m.msH oueme0 as 0.H m.H em.0 H0.0 as.0 o.em 0e.0 w.H 0.0 mmo0 NH 0m.0 Hw.0 0:.0 s. s mm.0 m.m m.0 mma0 0s mm.0 0m.0 No.0 m.sm sH.0 0.H w.m ma 0 we saw. <2 <2 <2 0.0 3.0 as To a .c. Hm.0 Hm.0 we. .mmus.0 $0.0 w.efi m.msfl 0maouemuo s 0m.0 ms.0 ne.0 m.fls NH.0 m.0 H.s «meg e 0m.0 me.0 0:.0 w.sm-0.0 Hfi.0 m.m m.mm «moo m mw 0.0: 0N.0 ms.0 se.0 0.HH 0H.0 m.H m.afi megs : 0.03 mm.0 0m.0 m:.0 .ss NH.0 0.m m.oH. menu m m.H Hm-0.0 mm.0 ms.0 ms.0 m.em-0.0 wH.0 w.o: :.m0m omaouemao m m.ms 0.mm 0N.0 0m.0 se.0 0.03 0fi.0 m.m m.sm meao H mms>emm mofiesflmm A550 2 . nfl\zv Apev Asmv % e Hum e mean a senssom .v spasm spew: geese oeyfiq meme 1] mflfide W...‘ -< T5 4: E\ .c. <3 T> ‘4 c: O c, C \ r’i c> .2. c: H O (\I 0) U cc . 0m.0 0s.0 no.0 c.ms 0m.0 m.0 m.m mg m om.0 me.0 ms.0 m.mH 00.0 m.m n.ew «mom on H.m N.m 02.0 ms.0 ec.0 m.se m0.0 H.m m.es we a sm.0 00.0 02.0 m.mm 30.0 H.m m.fie mugs s; g u n u u u u u u . cases mofimaem .z - u u a n u - . 0H.0 m.0 m.s «ago mm Hm.0 ss.0 me.0 w.s “.0 0.0 m.s ewe mm 0w.0 0m.0 ms.0 :.Nm mm.0 m.H 0.: seapoo Hm sm.0 em.0 ns.0 s.mm em.0 0.0 n.sm messes 0m mw Hm.o mw.o u:.o n.0m :fl.o 0.: :.mm maaeou 0H mm.0 Hm.0 es.0 c.0m 00.0 0.m w.sm ofimnoo as mm.0 Ha.0 ms.0 o.flm :H.0 0.H m.mfi osppoo es Ne.0 ms.0 as.0 0.0 mfl.0 m.m 0.:m .emwo ess 09.0 mm.0 09.0 m.ss ms.0 m.e 0.0 m0 0H mm.0 sm.0 s:.0 s.sH Hm.0 0.N mnm emcu ma mmfi>mmm mafipzfiom Nssv NJCDQ Amwu Idpmv % e Hon e mass m m he mgegm spews newcoq smoaospsq meoq 59.2.6 Ae.pcoov HHH> assay 00.03 00.0 00.0 33.0 3.00 00.0 3.0 0.00 .c0 03 .\ . 00.0 00.0 03.0 0.03 30.0 0.00 0.00 (000 03 00.0H 00.0 00.0 03.0 0.00 0fi.0 0.00 0.00 0000 00 d . 00.00 00.00 00.0 00.0 03.0 0.00 00.0 «.0 0.00 000 00 00.0 00.0 03.0 .00 00. 0.0 0. 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H 0. 00-000 33. 00. 03. 0.0.00 00. 0.0 0.30 $000 $3300 $3300 0000 .0 m 0.. 0020 £02.. 5003 0030305 0003 00 000 0.. 3.0000 meaSm <55 was” 0H9m.._._o_mwzam u e m mo? me e m ; _ Arll, , , .IIJrII_ _L, m. om mm_.m_. O ‘ t0 C) Q' mmmzoznom lNBOHEd C. ._~ : J . . L a . 1%), O N C) FD C) Q’ _m_ I, , om .m m. .m... NOXUV h-ZMU~h&MAi We) PERCENT 50., 40r- 20- IO l8. I 9 ’Tr‘T‘IF“ so 40 - 30- 20 TH—hr IBJQEiZO o 20 so so 0 2040 60 so ‘ ANGLE” P) 'v, - *" z .2: O . '.. l p 1.3-! .- 0,10,- ‘. .. ,. g L 1 Are 22 inclinalon 0.. Long 5339.; 0L Coon; as 1:“... 3.9.37.7-J3t to 99 measurements were taken on surfaces perpendicular to the bedding, except for lens #18 where the surface dipped 30 degrees from the perpendicular. The matrix of the cobble lenses consist primarily of sand grains in a serieite matrix with minor constituents of chert and vein quartz fragments. Eagnetite and leucoxene are also present. There is no primary hematite. Analysis of the sand grains shows thatthey are similar to the sand grains found in the CQSA lenses with values for mean size, roundness, and Sphericity of 0.31 mm, .b3, and .81, respectively. The grains are between 1.0 and 10.0 mm in size and exhibit sub-angular to sub-rounded shapes. The frequency distribution of the cobble lenses consists of four modes: the cobbles at 65.0 mm the fragments at 5.0 mm: the sand grains at 0.3 mm, and the serioite at 0.03 mm. H. Iron Formation Two distinct phases of the Negaunee Iron Pornation are found in the floors tine vicinity. The typical ferruginous chert phase is predominant, occupying all but a small strip immediately beneath a portion of the pyroclastic horizon to the east of the Hoore Mine entrance. This strip contains the jaspilitic phase. Both the ferruginous and jaspilitic phases are identical to those described and pictured by Van Rise and Baley in U303 Monograph 28 (2). In fact, the principal observable difference between the iron forma- tion here and in the main s*ncline is the resence of larce P o quantities of clastics. 1. 100 or the mos '5‘ a 1."! .u. te ar .emati scale ature ni a Ill"; ed on fold. ed and fault 1~ \J ortuou .L v v I follox CI‘S rt lav C One to be len 168.33 ’ ’17)?“ c,‘ " depos ... a iary node or prir er - .(wt .3} ran ' I 1‘. has cauSel on of f i c act ion, 4. V ,3 Li rohen an ‘C- 1 nsiveiy "Ln .‘av } to be e '- '. b I‘OC.~ 1.3 V V l t 01 portions 0 P - -'.. 33.9“?)(132 . O.— I (1 te I“; 1 . , 0 PT."". ~ .V. (‘4 J... 1 ‘sfi- n _' a n"... 3..QO..e ELL}. L1 - .I ’. 330 1151.8 v A Ll nned, o '3 th raps. t Fit 0 C.» -I‘ . 0 U resu1 filling in the f the 0 ~21 O O A | .— .L '31“). u C ~| encd, a 9 ,- .. thic~ .1. L; 50V..- Cher ~F‘ “J“ ‘L finnn w ova-n VJ ill—v f .- Al... (.va) o a . .— 1351” .33 C013 ., a ‘ ~4- ginous snort ferru. The 3 :rs knees nic -lng t Bedd ‘ «mg-'- Viavj—t O ( its and L L; 3'18. ' (V- ‘ J h . .1.‘ 1‘ caicns o; . . nd :1nndn., ' I has 5“. .nths « 1.55 vi 2,."an 9 down to l ’» r :n C .A0 I "I Y! :- layers vrx‘r‘ fi‘r v V- r 'J la 0 ~~ - ..b‘n. 1 .,<‘V V ’J. v. ‘A% 5' V! v- 1E‘dJ 3...) l ‘ 1‘ 05‘ out 101 Contcrted Feddin- in tne Iron Tornation ’0 102 no .3736: 'F‘ is. ,Tt‘fi ‘ ‘4: n betre rs.“ - -I\) . tn] 'ak~- . c". .,, IL and b’ ‘per - - ar‘l '3: Tau . 1'3 19 L~J blanketed by a .50 Zinc is ‘P A .f.‘ O n q, .- Sr 0.5 no: um l7. ‘- o jnaa I? P —U 'n .LLL conta‘ v H. h + p s‘ / .3 (IV). '1 .l r361 04“ “fiall sand C)- n both found 1 «vs x0.- U ! .'.fi\‘y“ A. \~ ‘.r'—. L .1. no i/ 031 a As]. Jo -, ‘A L .J (0 n 0 q I L.\ n!- -& :9 p730... -. . .e‘n d.— O L. V‘s-'fi‘.‘ \l— {L l O '39 l?" 3’.“ -sv.- .15“ *- Y3,'\v‘ ~\\')'.‘y<(-. :- u 3' '4. ' é—L-u_--| bro} -LL' 1.) . f}; .531” t.-;vvu’ .‘f‘ V“ ‘. .\1. ”(3‘ V b. 0 ~ _ O N (‘2: '1 fi- (e'fi fir: u)(o'. .L '14 :.~. p ‘- 5;! V ‘J Y. ,3 no ‘ -‘. 338v; ‘JA.( . .1 "3 n-fi a.» ’ f“? 0.1" O; 0’ ",I "I .2- "AA «‘0 O .. , ; _'... la_\.’.;~.; ‘L ,m l. O ,3 lave“ ' I w“ 4‘. J ' at L ° ,. p‘p‘nr‘ a JOLC [oi-I. LC: LI;- 103 spectrum from the background percentages up to no.0 to 60.0 percent. The mean size, roundness, and sphericity are similar to the CQ lenses. These concentrations make up the second p0pulation and could quite probably be classified as miniature CQA type lenses. The third population consists of concentrations of sand grains which can be related to particular elastic lenses. These concen- trations increase gradually as a lens is approached directly from beneath: but decrease rapidly above. Parameters of population III sand grains are similar to those of p0pulation I at significant distance from the lenses and approach pepulation II parameters when approaching a lens. At the lateral borders of many of the lenses, especially the CQ's and CQS's there exists high density zones of sand grains. These concentrations are directly related to the lenses and appear to be an overflow of clastics from the lens basin of deposition. The iron formation beds surrounding the lateral ends wrap around and pinch out these concentrations. I. Eyroclastic Horizon Striking approximately N7OOW from the point where the railroad track crosses the 28-29 section line to just past the Moore Kine, some 3/h of a mile, is a conspicuous pyroclastic horizon. This horizon has been previously reported on by Tyler and Twenhofel (23). Marsden (24), Eengle (26), and others. The regional map shows the relationship between the horizon and the area geology. At the western section line a width of 160 plus feet was measured (no pyroclastic-iron formation contact found) while at its easternmost n... . n. . O C .1 e .r. r 7. .0. at .. H .... . o a... .C L o .... ..u r ..-. 3 ... .... u a _ ..-. S S s i n x.) n 9 C t A... 3 1 .3 n i r O ,1 .... O r a. O r O G 3 ..- .F s. u... ...... O O O "J ..u n. a: q... 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E L0 10. a.“ o S ....n .0 3 O a... .1 M... O ...J ..D ”J O 3 a. 21.. fit. Av by C n. J Irv CO (J ...v n . _. 0Q firU V v a.“ I...” 0n.” “y. Riv ...“ ... .J o n .1 e n. u o C 1. z .. e .1 .C. n... .1 C i o .1 .1 ..-. .fi 0 O Q. n .L .. .... ... n” T .....e. U. n 3 3 ... ......M a .c 3 1 3 .t ...u S 2 3 ...i r... . R A... a w . 1 . O .n ....u a... n a... 3 1...... C "a .7. . ...u 0 O O ”Q Q. a S .... ...U is h... .1 i e O 1 ... d l .. e 8 s b 3 f e m .. o a E Z C u C is S .-. 2 n A 3. .0. e O S A... 3 3 ....” O A; ...; ..b e O l .1 1 o G e n L o ..D C 1 . 1. m. .1 O S n L V .n ~ n 3 n r H... w t ql. O C n: Y _ 1 :J. K O .r.“ .l ”l v... c ...o O h K e .r n 0 v o n .l O t ...; h u C .n t d ..... . f I t t C t .1 .1 .. . .0 i“ T f .1 .c .... .1 d 7.0 O .1 “n ‘- 1'10 105 5‘1 ‘9 Ud.J ..L . .- an (3;. VI 31.; (:0 K-‘ o I. .- of selocte V, J stud - 4. -~. 033.01J ‘n 8. L 't. llnl at least two 3 €2,217]. 4 v“ 1 I nv’v- by FTP] 13‘." adv.on resent, an n... J. 9 u color du U o .' s . eoni~ , -, . Y. rock tones on " {1c} ..Tv a" ..l'\. matr moderately alterofl A ’1 s) K, v\ 6 gm? 1 hon n"C 4.5... f » nod 7010 I g .c .1. .LC COP. .8.~ .1 Q ‘ It? ..00 Lo: .0 JV"‘I‘3 ‘ d 'g. "r 0V J.~ of: the env OH. 0 '11", (I hor aJ-n -‘ J P4"? 44~-~.\r‘ -‘h 0.33 coniact 2 L1. . ..\ 1 --1-3 f‘...€'- lash c; -510 n I‘ (n o + ._.. , ‘ D+'.’.“-.‘JV1 \JJ 4" III-- ‘1'7'10 ...-3--.! a. 8.?! o at ...-L: ~-' 4.5., L I ( yrocl 91 J A I 1.3 30 L-S 1 . The dike . 02“ V 1 - 1. J” v .1 lost no :3 3 ”r1 ’3 " '.‘ L (.0,- . r C' It??? I'JV I w. 4.5 (v-- of chert, d. A J l: L 3'3 J JrI\‘- fl K“ 5 .LC .‘—V0 l. T“!“Lfi"'\ 1 .3“ + ‘ 3'13 0 l" : 3 O and boulfi. ty and nericitic few 1 rom 5 v Cher 1e J p 4 an ~“. A 5 (1:1; ... {13‘0“ O I 0 q .\ ._v\’ ..u)\r-J ‘1'? :v- 106 Dortl ob1n 1 '1 .lth- ‘ 53'” h :1ar be out ‘ (u 0 o in l x. ..L 'fin ... 7-" .-o 4 A ) O I u- | +. J .I‘” ...}- .a?o£‘/\ .u-. U .-I 70 '1) Along the en «D on" «J I .. g .. , ..., .. ...... 1.“ 3. 3 a. I 3 .3 3 3 a 9 .. C 3 3 -. . ..L . g ”I 8 .. .. 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C 0 no .1” .23 L v 5: flu 91* v .. O n . ups Lvt v. . 4 2"”) vs“ 1 L; 37 ”3'1 ~V~ b .0 4 r. P‘fir.fi%' ‘ J...z.. ax) 107 «:33 .8» _ QUE mam ..302 as: coummom cfipnwfio .zm okzwfim 3:38 .2. :000m 2 .5. “Boom v *- a ion ‘4 :OO ‘7 ,. b ormat D 3 J oh -holOgy o? + J ~ iron CS v 1,! on a 1n 0 ; 9: .L t o I ‘ m ’ dnfi ‘3 l q .. 108 o are r .n a mum} \ and (Looa 3;; I the J. '4 ” 1a 1 Section III. SIP .tion D- ~3 of elastic quart” pat]: on 0 es ' d in .1. 'v A ... d b i ., ..1 J. t ‘- LOG-‘3 t. B. this 10 :1qu desc F,’ S e ‘ snape. «(Una-:37 "lh ‘/.'.a plane-v vv W1 11"lav-xl flow . O? a o Cl—COH'J 01’ a. r :5 4 I §- ‘0. S sani coarse O L \- J o a I 1'. y‘l nougo ,4 (ad.- IN < :3 v r ’ 31.; O u f”. .3 \1 bank u~ m 0.70 :7... -..U VT; 1v ( T D angln .L .! ‘ r o :d pebbles ha nu 0 ... v~ c. ~nes 1H" XLLA .- n C n) \n x Y‘ 4 1‘9 320‘ {no ISA ) q «34" V . ‘ ifi‘) ~ ‘1 47"..) v n. ‘y from 0.99 do b.1031 Loco 4-- 0.09:: formation 1 *1- - thy. o..' I n A.“ ....q I (I chert lj‘j fin olwc L in other 0 fl 0 .L, .‘3; {Hr v.0 r ‘1 1 With chertv qua ,. ,4. 109 ‘11. a O ‘L Lcturod and a C vs f; a O {- Q ranule ~T 0 ”art C 8001a- traformationnl br abundance in the hema 1n r laye 34 ..1 A. 7 [TV r J herb, and qua P. A- '4. it L '4 ma~ -l\ l a. n— L v 7‘ ...-A I 1 -A ltcrOp here on one outcronr th the iron 60 V Ni {“1 L351 ~-A v -. I fig '. or lenses 0 orb '1 ¥ .‘-1 .-~.J an anomolous “ n h) n 5) 3. . 0 Ear § 1 T HI V I o '1 (by «1331‘ III" (TV L FLA (Location TAR (Locat (Loc C‘ u poscf S ‘1" .L I r\~p -~\ v0. .- I.) D v Lo ...“! 1 , .....- o variou~ X 10. 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U4 3;. .at 1 s Lyv r1 -... 1‘. 1. ‘J v -l. 730:. ‘7)vfirf- A.“ -\J ‘ L-m U \ O 10.”. .0 .1. .. inufuu OT.‘ :-?~-‘-" \A... ‘JJ ch 'P'vtn - k n'.’ V‘"f\7' -. ‘J \J- u 5-; slifle o ’n \ \_. V‘ \1/ 50 ,L V 13 '7 '. u , \ 12 a -:3“+‘- ' --‘ d--"-4 .. - 3 ° ‘ , . A! “4 o 3. o _ _ q . Sa‘BK‘. ‘. q ~3rl 'fir' “Ana/3 4.-...O._;. J». L r""“ .)*. '. -~fi ' v lirannént 217‘“ .'5 mm" ‘-~ 0 ‘ ~J. ' O Sahafl’jvsl‘ 1...? ’d\l nt. 0 ‘1‘ on - 0'12” 7'1 ml 0 a“ '3 ("3 ....V '7 ’\ A: (5 .2 -91..- .t 'V L411. 0 : P9‘,‘ 7130; “ n Q‘u‘?‘ [‘7' o ._ .‘ -t - .\4 «é'nn V —’4 ‘ “‘0‘ hfs‘ ' ude C .‘C, had- I’i‘ O 0313' 3'. 124 here includes the various factors involved with the movement of the sediments from the basin shore line and the physical conditions under which they were deposited. Iron formation-elastic relation- ships are summarized followed by a discussion of each of the major elastic lithologies in terms of pertinent factors relating to their physical depositional environment. Iron Formation - Clastic Relationships The relationship between the elastic lenses and the surrounding iron formation was studied in some detail. The characteristics of the iron formation do not appear to change as one approaches or recedes from a given lens except for the additional influx of sand grains previously noted. At the boundary line there is a marked border surrounding each lens consisting of broken and sheared material (mostly iron forma- tion) now in a degenerate, crumpled state. Usually this border is less than an inch wide, but for the 0qu lenses (#2, #7. and #12) it extends up to several feet. EXamination indicates that the zone is probably the result of post-depositional effects, primarily structural disturbance along the dislocation between these two bodies. The question arises regarding the conformity or unconformity of the clastic lenses to the enclosing iron formation. It is true that many. if not most, lenses are unconformable if one considers only a layer or two directly beneath the lenses. Study on this scale indicates that most lenses lie directly on a chert layer, it is believed that the hematite layer being quite ”soft" and thus having a low erosion resistance was swept away as elastic deposition progressed. Often a 125 portion of a chert layer has been displaced and can be seen lodged a few feet away near the base of the lens. To the author it appears that such a case of unconformity is typical during all changes in elastic deposition and as such indicates a perfectly normal condi- tion. In order to best utilize the relationship between iron for- mation and elastic, the word conformity must be defined in terms of this study. Conformity, in this study, is restricted to the gross effect, to include a zone encompassing at least several layers of chert and hematite. Applying this definition, 38 of the #2 lenses can be classified as conformable. There are three types of conformable relationships found at the Moore Mine. The most common is where the elastic material forms a "lens shape" deposit and where the surrounding iron formation completely conforms. Usually the iron formation below the lens is depressed slightly, rarely is the overlying iron formation arched significantly. A number of lenses exhibit a gradation with the iron formation at their lateral ends, while on tap and bottom they are conformable: lens 16-A is a good example. Three of the CQA3 lenses exhibit an unusual lateral contact with the iron formation, each exhibiting serrated edges giving the appearance of miniature on-lap, off-lap. A number of apparent unconformities can be explained by post: depositional structural movement, jointing, folding, and faulting. Ten lenses are at least in part structurally controlled. Lenses #20 and #21 provide examples where folding played an important role in the lens shape, both having been doubled over. 126 Four lenses exhibit definite unconformable relationships with the iron formation. The western portion of lens #18 is a good example of a channel cut into the underlying iron formation. Several feet to the east lies lens #16, a large quartzite block which has been emplaced within the iron formation. The iron formation abuts against the block on three sides, only on the t0p is there a con- formable relationship. Two other lenses, #26 and #36, demonstrate an unusual type of unconformity. 0n the base of each lens the clastics cut obliquely across the iron formation, resembling a deltaic deposit rather than an erosional surface. Each lens at the Moore Nine can be placed within the following iron formation-elastic classification: 1 . Conformable (a) Normal: all lenses except l-b, c and 3 (b) Gradation: lenses 3, h, 16-A, 30, and 31 (c) On-lap, off-lap: lenses 38, 39. and no 2. Structurally Unconformable (a) Jointing: lenses 2, 12 and 19 (b) Folding: lenses 20, 21 and 37 (c) Faulting: lenses 2. 12, 2h. 25, 26 and ul 3. Unconformable (a) Channel out: lens 18 (b) Oblique cut: .lenses 26 and 36 (c) Abutment: lens 16 Figure 25 presents idealized sketches of selected elastic lens types. ' 127 TRUE LENS ON LAP - OFF LAP Figure 25. Idealized Sketches of Clastic Lenses 128 CHANNEL~ CUT \— 5 ——— I " . > W— .___._————-—-—-— «W t e ABUTMENT Figure 25. Idealized Sketches of Clastic Lenses (cont'd) 129 Clastic Lithologies Cobble Deposits: The cobble zone deposits can be classified as protoquartzitie conglomerates. They appear to be typical river or stream deposits as evidenced by their size distribution and shape characteristics. It is believed that these cobble lenses represent a branching river or stream deposit whose Open voids were later- filled in by the matrix sediments. The cobbles themselves are well sorted indicating a high velocity, shallow water deposit, possibly at a time when the iron formation was above wave base. The matrix, on the other hand, is poorly sorted indicating a deeper water deposit. The cross section of the lenses indicate that the direc- tion of transport was north, while the long axis of the cobbles appear to be oriented perpendicular to that direction. The numerous isolated cobbles found throughout the elastic horizon are thought to have reached their present positions by rolling down slepe along the bottom of the basin. Deposition of the large quartzite block (lens 16-A) is an enigma, rolling or less likely ice rafting is called upon. The absence of broken rounds places an upper bound on the transport velocity. Chert-Clay-Sand Deposits: The CQSA-CQSC lenses represent a rapid deposition as evidenced by the turbulent textures found at the base of the lenses, by the angular fragments and by the poor sorting. The transport medium must have been of high density since coarse and fines are intimately mixed. It is believed that for the most part these lenses are the result of turbidity currents and/or slides. For some of the lenses it appears that at least half of 130 the material was deposited during one occurrence with the larger fragments settling to the bottom. This may explain the gradual decrease in the fragment size from the bottom to the middle of the lens. From the middle up, the fragments become larger, indicating possibly a new influx of material. The broken chert layers along the bottom indicates that the transport medium possessed a current velocity of considerable strength. The CQSB lithology represents a similar deposit but with lower transport velocity. 'The CQSD lithology is probably the result of current deposits: fragment size and lack of primary hematite indicate that the current velocity was strong. The transport medium was not as "clean" as in the case of the CQ's but, on the other hand, was not as dense as that indicated for the CQSA's. Clay-Sand Deposits: The serieitie quartzites (QS) are believed to have been deposited by currents where the velOeity was sufficient to orient many sand grains with long axis parallel to the strike. Since this is the only lens deposit not containing chert it is suggested that deposition occurred above wave base. The roundness and sphericity of the sand grains are significantly different from those of other lenses possibly indicating a source outside the basin area. Clay-Chert Deposits: The origin of the serieitie chert (CS) lenses is unknown. One hypothesis is that they represent deposition within a naturally formed depression below wave base. The reason for the absence of hematite and the formation of chert globules is unknown; but is probably related to the chemical environment. 131 Sand-Hematite-Chert Deposits: The cherty quartzite (CQ) lenses represent off-shore current deposits flowing essentially perpendicularly away from the shore line. The roundness, sphericity and sorting of the sand grains and the complete lack of clays are indicative of reworked sediments, probably Ajibik and/or Mesnard derivatives. While the sand grains were being transported from the reservoir of beach sands and deposited along the current path, hematite and chert were being chemically precipitated. That the sand, chert and hema- tite were deposited concurrently is evidenced by the uniform dis- tribution of sand grains in the hematite-chert matrix and by the homegeneity of the lenses. Each particular subgroup retains the above general characteris- tics but differ in one or more specifies. The CQA1 and CQA2 sub- groups exhibit a high percentage of primary hematite indicating that current velocities were quite weak. The CQA3 and CQB subgroups, on the other hand, exhibit a lower percentage of primary hematite and a greater percentage of sand grains indicating a stronger current velocity. The intermittency, thinness, and lateral extent of the cherty quartzite beds in the New Richmond Mine area are indicative of currents which are less persistent and more varying in velocity and direction than those to the west. Sands: The percentage of sand grains evenly distributed through- out the iron formation, population I, are believed to represent wind blown sands from the basin edge. The local, small sandy lenses and zones, pepulation II, are the result of isolated currents. 132 Table XI presents a relative transport velocity index which has been worked out for the hoore Mine area. It is based upon a com- bination of textural and compositional characteristics of the elastic deposits and their relationship with the iron formation. It is significant to note that while there is a continuous grade between indices, a particular lithology usually can be indexed within a very narrow range. When viewed in its entirety, the clastics at the Moore Mine are found to form a steady pregression toward normal iron forma— tion depositional conditions as one proceeds upward from the base of the Negaunee. With increasing distance from the base of the Negaunee, the velocity index, sand and clay content and quantity of fresh unworked sediments decreases while the degree of sorting, homogeneity and general maturity of the clastics increases. Chemical Depositional Environment: It was not the primary intent of this thesis to evaluate the chemical environment. How- ever, in the course of this study certain interesting factors which bear upon the chemical environment have emerged and are discussed below. Considering the total deposition in the Palmer Basin, it is obvious that the chemical environment was the major controlling factor in the deposition of the hematite and chert during Negaunee time. It is hypothesized that a sufficient quantity of iron and chert were continually supplied to the basin with their deposition being_precisely controlled by the Eh and pH conditions locally present, see Garrells (35). This continuing, cyclic deposition INDEX 1 10 133 cant thickness of iron 4 formation. Table XI TRANSPORT VELOCITY INDEX FOR CLASTICS AT THE MOORE MINE * STRENGTH DESCRIPTION EXAMPLE Nil Iron formation bedding undis- Majority of turbed, sand grain content the iron less than 5%. formation Very weak Iron formation bedding essen- Iron forma- tially undisturbed, sand tion with grain content up to 153 for sands pepulation II and up to as; for pepulation III. Weak Iron formation bedding Very small absent, localized small lenses and pockets of hematite, chert sandy zones and sands . Very Mild No iron formation bedding, CQAZ lenses sand, hematite and chert deposited together. Mild Homogenous mixture of sand, CQA3 lenses little primary hematite and chert e Iormal Non-homogenous mixture of CQSD lenses sand, little primary hematite and chert, with scattered fragments. Moderately Sand grains are oriented with QS lenses Strong long axis down dip. Strong Long axis of cobbles are Cobble lenses oriented down dip. Very Immediate underlying beds are CQSA lenses Strong eroded away, clastics include unsorted material. Extreme Channel cuts through signifi- Cobble lens #18 .13“ of hematite and chert was locally modified from time to time by the influx of elastics. The clastics altered the Eh-pH balance, temporarily ceasing the deposition of hematite (CQ lenses excepted). It is interesting and important to note that deposition of chert was usually not terminated during elastic influx. Chert is found as a component cf the matrix of all but the Q3 elastics. It would appear, therefore, that while deposition of hematite was sensitive to the Eh-pH condition, chert was not. It should be noted that the deposit of a elastic lens was restricted laterally and did not appear to influence the iron forma- tion deposition on either side of a lens area. Disconformities were not observed in the iron formation on horizons contemporaneous with a elastic lens. The general nature of the clasties and their relationship with the iron formation would iniicate that the Negaunee at the hoore Mine represents a shallow water, near shore deposit. This tOgether with the primary hematite in the cherty quartzite lenses provides evidence that the area is the equivalent to James' oxidation zone (3b). Study of the iron formation-elastic contact indicates that the chert layers became hard soon after deposition while the hematite layers did not. Where the iron formation-elastic contact can be clearly examined, the chert layers are found to usually provide the base. In addition, there are numerous examples of chert fragments deposited in the lenses; few hematite fragments have been found. ‘ 135 SECTION VI CONCLUSION Following are the more significant conclusions reached during this research: 1. The Negaunee Iron Formation, along the southern edge of the Palmer Basin, represents a shallow water environment within the oxidation zone where the chert and hematite were both deposited in a primary state. Deposition of the hematite was sensitive to the Eh and pH conditions of the water: deposition of the chert was not. 2. The various clasties interbedded with the iron formation represent normal depositional conditions. These clasties were deposited in the basin both during iron formation deposition and during intervals when portions of the basin were above wave base or even above water level. During these latter periods the hematite and chert layers previously deposited were re-worked; the hematite being washed out into the basin, the chert worked by waves and currents and re-deposited. 3. The provenance of elastic sediments was a low lying land mass located a few miles south of the Negaunee Basin. Within this provenance the major source of the sands was the semi-consolidated Ajibik, the Nesnard provided the quartzite fractions while the Palmer Complex and Kona contributed the granite and shale fractions tagether with the heavy mineral suites. h. Lower Huronian Mesnard and Kona formations were metamorphosed prior to Kiddie Huronian Ajibik and Negaunee deposition. 136 5. Material was transported from the provenance to a broad shore line bordering the Negaunee Basin where the sediments were extensively reworked, with the sands retained and the clays winnowed out. On occasion the provenance provided sediments directly to the basin.- 6. Clastics were moved from the shore line into the basin by one of five basic transport mechanisms depending upon the particular lithology: winds, off-shore currents, streams, traction and slides and/or turbidity currents. 7. As Negaunee time progressed maturity and stability of the provenance increased. As sediments were transported out into the basin, the shore line reservoir was not replenished and elastic deposition ceased. 137 REFERc. ess -1. Van Rise. C.R.. and Leith, C.K., "The GeolOgy of the Lake Superior Region," U.S. Geological Survey Monograph 52, 1911, 6&1 pp. 2. Van Rise, C.R.. and anley, W.S., "The Marquette Iron Bearing District of Michigan," U.S. GeolOgical Survey Homegraph 28, 1897, 608 pp.' 1 3. Schoolcraft, H.R., "Narrative Journal of Travels from Detroit Northwest through the Chain of American Lakes to the Source of the Mississippi River in the Year 1820," Albany, 1821. h. Houghton, D., "Fourth Annual Report of the State Geologist, Douglas Houghton,” House of Representatives. State of Michigan, Report 27. 18h1. 5. Locke, J., "Report of John Locke to Dr. C.T. Jackson, Describing the Observations Made on the Geology of the Mineral Lands in Michigan," Senate Documents, V. 2. No. 2, 1847, p. 183-199. 6. Burt, W.A.. "Tepography and Geology of the Survey with Reference to Mines and minerals, of a District of Township Lines South of Lake Superior," Senate Documents. V. 3, No. l. 1850, p. 811—832. . 7. Foster. J.w., ”Notes on the Geology and Tepography of Portions of the Country Adjacent to Lakes Superior and Michigan, in the Chippewa Land District," Senate Documents, v. 3. No. l. 1850, p. 773-801- 8. Foster, J.W., and Whitney, J.D. "Report on the GeOIOgy and Tepo- graphy of the Lake Superior Land District," Senate Documents, V. 3. NO. an 18.51! “'06 PPO 138 9. Kimball, J.P.. "0n the Iron Ores of Marquette, Michigan,” American Journal of Science, V. 34, 1865, p. 290-303. 10. Daddow, S.H.. and Bannan, 3.. "Coal, Iron, and 011; or the Practical American Miner," Pottsville, Pennsylvania, 1866, p. 5h6-550. 11. Columbia University, "The Marquette Iron Region," School of Mines Quarterly, V. 2. 1882. 12. Rominger, C.. "The Marquette Iron Region," Geological Survey of Michigan, V. h, Julius Bien, New York, 1881. 13. Winchell, N.H.. "The Iron-Bearing Rocks at Marquette, Michigan," GeOIOgical and Natural History Survey of Minnesota, Sixteenth Annual Report for 1887. 1h. Wadsworth, w.s.. "A Sketch of the Geology of the Iron Cold, and Capper Districts of Michigan,” Nature, 1892, p. 117. 15. Lamey, C.A., ”Granite Intrusions in the Huronian Formations of Northern Michigan," Journal of Geology, V. 39, 1931, p. 291. 16. Lamey, C.A., "What is the Palmer Gneiss," GeolOgical Society of America, Proceedings, 1932. p. 92. 17. Laney, C.A., ”The Intrusive Relations of the Republic Granite," Journal of Geology, V. #1, 1933. p. #87-500. 18. Lamey, C.A., "Some Metamorphic Effects of the Republic Granite,” Journal of Geology, V. #2. 193“. p. 2h8-263. l9. Laney, C.A., "The Palmer Gneiss." Ge010gical Society of America, Bulletin, V. #6, 1935. P. 1137-1162. 20. Lamey, C.A., ”Republic Granite or Basement Complex," Journal of Geology. v. u5, 1937. p. 485-510. 139 21. Dickey, R.M.. "The Granite Sequence in the Southern Complex of Upper Michigan," Journal of Geology, V. #4, 1936, p. 317-340. 22. Dickey, R.M., "The Ford River Granite in the Southern Complex of Michigan," Journal of Geology, V. 46, 1938, p. 321-335. 23. Tyler, S.A., and Twenhofel, W.H.. "Sedimentation and Stratigraphy of the Huronian of Upper Michigan," American Journal of Science,- V. 250, 1952. p. 1-2? and 118-151. 2h. Marsden, R.V., "Pre-Cambrian Correlations in the Lake Superior Region in Michigan, Wisconsin, and Minnesota," Geological Association of Canada, Proceedings, V. 7. 1955. p. lot-115. . 25. Vickers, R.C.. "Geology and Monazite Content of the Goodrich Quartzite, Palmer Area, Marquette County. Michigan," U.S. Geological Survey Bulletin 1030-?, 1956, p. 171-185. 26. Mengle, J.T.. "The Relation of Clastic Sediments to Iron Forma- tion in the Vicinity of Palmer, Michigan," Unpublished M.S. Thesis, University of Wisconsin, 1956. 27. Sahakian, A.S.. Unpublished M.S. Thesis, Michigan State University, 1959. 28. Long, R.A., "Origin and Petrology of a Portion of the Southern Complex Near Palmer, Marquette County, Michigan,” Unpublished M.S. Thesis, Michigan State University, 1959, 35 pp. 29. Rosenberger, E.J.. "The Relationship of Huronian Sediments to Associated Igneous Rocks in Section 22 and 23, T.h7 N.. R.26N., Marquette County, Michigan," Unpublished M.S. Thesis. Michigan State University, 1961, 59 pp. 1&0 30. Krumbine. V. C.. and Pettijohn, P. J.. "Manual of Sedimentary Petrorraphy." Appleton-Century-Crofts. 1938. 3&9 pp. 31. Krumbine. V. C. "Size Frequency Distribution of Sediments," Sedimentary Petrology. Journal. V. 18, 1938, p. Rh-QO. 32. Pettijohn, P. J.. "Sedimentary Rocks, " Harper and Brothers. 1949, 690 pp. 33. Krumbine, V. C. and 31055, L. L., "Stratigraphy and Sedimentation." Freeman and Co., 1958. 3h. James H.L., "Sedimentary Paeies of Iron Formation," Economic Geology. v.49. 1959. p. 235-293. 35. Garrels. 3. M.. "Mineral Equilibria at Low Temperature and Pressure," Harper and Brothers, 1960, 25h pp. 1&1 APPENDIX A CHEMICAL TESTS A. lptroduction This appendix presents a report on the chemical tests performed in the deve10pment of a technique for disaggregating some of the metamorphosed clasties from the study area. Documented are the step by step results obtained, substantiating that the deve10ped disaggre- gation process is valid and when properly performed will yield sands statistically similar to the original sands in the outcrop. Analysis of these disaggregated samples provides an important key to the origin of the iron formation elastic. See Section III-D for a discussion of the analysis.. To the author's best knowledge such a disaggregation process has not been reported on previously. B. Summary The first disaggregation method tried (Experiment 1) consisted of alternately freezing and thawing elastic samples saturated with various solutions. This method is dependent upon the degree of permeability of the specimen, which for the samples tested was very low. After 288 hours of alternating the two conditions, no disaggregation was observed in any of the samples. It was found that due to the extensive hematitic staining it was impossible to sufficiently analyze the specimens either in polished section or in thin section. Krumbine and Pettijohn (30) suggest the use of hydrochloric acid and stannous chloride to remove iron oxide. This process was adapted with a slight modification (Experiment 2) 1&2 wherein hydrochloric acid was used in a concentrated form (36.5%) and only enough stannous chloride added to maintain the iron in a soluble state. The HCl-SnC12 solution worked quite well in de- staining the elastic samples; in fact. it was noticed that samples left in the solution for a few hours began to deteriorate. The next experiment (Experiment 3) was performed to determine if this deterioration effect could be increased to a point where a partial or even complete disaggregation of the sample would occur. Using the procedure described. all samples were completely disaggregated after 16 days of immersion.' The residue consisted of sand grains encased in a chert cement. EXperiment 4 documents the use of potassium hydroxide solutions for*dissolving this chert cement; normally accomplished after five hours of boiling. Once a.disaggregation process had been deveIOped, it became necessary to determine what effect the HCl-SnClz and KOH solutions had upon the quartz grains. Experiment 5 provides evidence that the HCl-SnClz solutions. acting for periods up to 36 days. had no measureable adverse effect on quartz crystals or sand grains. Quartz crystals were used for surface texture study. The sixth and seventh experiments dealt with the effect of boiling KOH solutions on quartz crystals.and sand grains. It was found that a moderate KOH solution ‘with a.boiling time of less than six hours provided adequate "cleaning action" while limiting the percent weight loss of the quartz grains to less than 0.8%. ExPeriment 8 showed that quartz crystals were 'unaffected by immersion in standing solutions of XOR for periods up to twotmonths. EXperiment 9 was conducted to'determine the Optimum A 1u3 solution strength and boiling time needed to yield the cleanest sand grains within the formulated safety limits (solution strength 80-20* and boiling time ~ 6 hrs). Only an 80-20 strength solution boiling between 3 and 6 hours produced a final residue of well cleaned sand grains. It appears that a 90-10 solution boiling for 8 to 10 hours may produce similar results. Finally, the entire disaggregation process of HCl-SnClz solution and the 80-20 KOH solution were tested on a typical beach sand (clear surface texture) with round- ness. sphericity. and sieve analyses serving as test criteria. It can be stated with considerable confidence that the deve10ped disaggregation process produces no measurable effect on the resul- taut sand grains. C- lies EXPERIHENT 1 FREEZING AND THAE-IIN Objective: To determine whether a process of alternate freezing and thawing will produce disaggregation in the elastic samples. Procedure: Six specimens of a cherty quartzite (CQAI) from the New Richmond Hine were divided into three groups containing two samples each. Two groups were subjected to a solu- tion of concentrated hydrochloric acid for one week. one was further subjected to a boiling KOH solution for two hours. The remaining group was not treated. One sample from each group was placed in a centainer of distilled *80$ by volume H20 and 203 by volume KOH. Results: Objective: Procedure: Results: *HCl-SnClz 11m water. the other in a container of hypo-solution. The six samples were then alternately frozen and thawed - 24 hours at ~10°C. 24 hours at 70°C, 2h hours at -lO°C etc. No disaggregation was observed in any of the samples after six complete cycles of #8 hours each. EXPERIMENT 2 DE-STAINING To determine the Optimum procedure for removing iron oxide stain from semi-polished sample surfaces and thin sections using an HCl-SnClz solution.* Evaluation of the effect of such a solution on jaspilite is a second objective. Portions of two different cherty quartzites (CQAZ) and a jaspilite from the Moore Nine were placed in an HCl-Sn012 solution for three hours. Samples were washed and examined under a binocular microscOpe at fifteen minute intervals. A similar test was run using a boiling solution of HCl- SnClz. Finally. a thin section of a cherty quartzite (CQAZ) from the hoore Mine was subjected to the above tests. Optimum destaining was obtained by soaking the samples in the HCl-SnClz solution for a time interval between fifteen and thirty minutes. Subjection for times greater than thirty minutes led to surface deterioration; solution consisted of hydrochloric acid of 36.53 eoncentra-- tion with enough stannous chloride to maintain the iron in solution. Objective: Procedure: 1&5 with longer subjection times the samples began to dis- aggregate. It was found Sufficient and desirable to place only that portion of the samples to be destained in contact with the solution. The above procedure was not applicable for thin sections due to a chemical reaction between the solution and cement. Even after seventy-five hours of boiling in the HCl-SnClZ solution the jaspilite sample was only "cleaned up": little. if any. removal of the red coloring from the chert bands or disaggregation of the sample was observed. EXPERINéNT 3 DISAGGREGATION (1) To determine whether the elastic samples can be completely disaggregated with the HCl-SnClz solution. to determine the rate of disaggregation, and to analyze the residues. Three cherty quartzite (CQAZ) samples from the Moore Mine and one cherty quartzite (CQAI) sample from the New Richmond Mine were washed. dried, weighed. examined and placed in 250 ml beakers containing 200 ml of HCl-SnClz solution. A 100 ml of fresh HCl was added every four days. At the finish of the experimentthe residues were again carefully washed. dried. weighed and examined. ’ 1M6 Data: Sample - Type Location Sample Wt. Residue Wt. % Loss (eramS) (grams) #173 CQA2 Moore Mine 30.2 20.9 30.8 #173 CQA2 Moore Mine 5“.9 37o3 32.1 #173 CQA2 hoore Mine 27.3 18.6 31.7 #302 - CQA1 New Richmond Mine 61.2 “8.8 20.3 Results: After 16 days all samples were completely disaggregated. Analysis of the residues showed that the samples had been broken down into small clusters consisting of several sand grains bound tOgether by a white crystalline substance identified as chert. No traces of hematite were observed. EXPERIMET h 8 DISAGGREGATION (2) Objective: To determine whether the chert portion of the elastic sample residue can be dissolved with a solution of potassium hydroxide. Procedure: The residues from the third experiment were examined. washed. dried. weighed and placed in 250 ml beakers con- taining 200 ml of potassium hydroxide solution. Each preparation was boiled for five hours. At the end of five hours the residues were again carefully washed. dried, weighed, and examined. 147 Data: Sample Type Location Sample Wt. Residue Wt. % Loss (grams) (grams) #173 CQA2 Moore Nine 20.9 1h.7 29.7 #173 .CQAZ . Moore Mine 37.3 25.6 3l.h #173 CQAZ woore wine 18.6 12.9 30.8 #302 CQA1 New Richmond Kine h8.8 35.5 27.2 Results: After five hours of continuous boiling most of the fine chert had been dissolved. All sand grains were singular - none being bound in aggregates by the chert cement. 'EXPERInsz 5 HYDROCHLORIC ACID AND QUARTZ Objective: To determine the effect of concentrated hydrochloric acid on sand grains. quartz crystals. and quartzite fragments. Procedure: Samples prepared for testing were examined under a binocular microscOpe prior to washing and drying at 70°C for 2h hours. Particular emphasis was placed on the surface condition of the specimens. A control specimen identical to the test specimen was kept for post-test comparison. Once weighed, Specimens were placed in 250 m1 beakers containing 200 ml of concentrated HCl (35.55 . Enough stannous chloride was added throughout the experiment to keep the iron in solution: 100 ml of fresh HCl was added to the beakers every four days. Duration of the test was 36 days. At the end of the experiment specimens were thoroughly washed in distilled water, dried at 70°C for 2h hours. and weighed. All specimens were then re-examined. 1&8 Data: Sample Sample Wt. Residue Wt. % Wt. Loss (gramS) (grams) Indian River Beach Sand 50.52 49.48 2.06 wesnard Quartzite Made uh.76 0.13 Clear Quartz Crystals ' 19.20 19.19 .0.05 Milky Quartz Crystals 17.17 17.16 0.06 High Quality Clear I Quartz Crystals 20.81 20.78 0.14 Results: Home of the samples exhibited a significant weight loss with the exception of the Indian River Beach sand. The Indian River Beach sand contained approximately 25 car- bonate. Re-examination of the surfaces and comparison with the control samples showed that the tested specimens suffered no surface textural damage due to the HCl-SnClZ solutions. It is concluded that the HCl-SnCl2 solution had no effect on the specimens tested. EXPERIMENT 6 KOH BOILING - QUARTZ Objective: To determine the effect of boiling potassium hydroxide solutions of varying strengths and boiling times on the percent weight loss and surface texture of quartz crystals. Procedure: Five KOH solutions of the following strengths were pre- pared: 60-30. 70-30, 80-20, 90-10, and 95-5. The nota- tion 60-40 represents a solution containing 60% by volume of H20 and #03 by volume of XOR. Such a solution is Results: 1h9 prepared by adding KOH pellets to 60 ml of distilled water until the meniscus is raised to the 100 m1 mark. TwO sets of matched pairs of quartz crystals were used for each solution: one pair being a milky variety of quartz; the other, a clear variety. These quartz crystals were of high quality with shiny faces and sharp edges. Long diameters varied from 15 mm to 35 mm, while the weights varied from 2 gm to 7 gm. A total of 2h crystals were used.' From each group of four crystals. one milky and one clear quartz crystal was placed in each solution: the other two were held as controls for post- test comparisons. All crystals were examined under a binocular microscoPe and their textural characteristics recorded. The crystals were first placed in an oven at 70°C for 2h hours. cooled, weighed. and placed in their respective solutions. Total boiling times varied between four and six hours with each sample being weighed at each hour time period. After boiling the samples were rinsed in hydrochloric acid, thoroughly washed in water, dried. and weighed. Textural charac- teristics were compared to the initial data. Finally. a control set of quartz crystals were processed in the above described manner in 1003 distilled water in order to ascertain the effect of tumbling in a boiling solution. A graph of percent weight loss of the crystals as a function of time is presented in figure 26. It appears 150 L6 '- IJG" |.2- Qtz XI "fl Sand ---- ll- 0 ’l&)- PERCENT WEIGHT. L038 0 I 2 3 4' BOILING TIME (hr) Figure 26. Percent Weight Loss for. Various KOH Solutions as a Function of Boiling Time 151 that the percent weight loss of quartz crystals is insignificant for KOH solutions of 80-20 strength and less with boiling times not longer than six hours. It is. however, fully realized that the strengths reported are initial strengths and that these strengths are increased due to water vapor escaping during boiling. In fact, the solutions became so strong that testing had to be run in intervals because the pyrex beakers would last only a few hours before dissolving. Further, the percent weight data represents a maximum loss due to mechanisms such as chipping and spallation of the crystals and removal of foreign particles. One must be careful that all the KGB is removed from the crystal prior to weighing. During the early part of this experi- ment it was found that by not rinsing the crystals first in concentrated HCl a quantity of KOH would remain on the crystal surfaces. Upon comparison of pretest and post- test specimen surfaces, a noticeable degree of chipping of edges, stiration of faces, etc., was found to occur. Since the crystals from the 1005 water solution also exhibited such wear, it is concluded that_such surface markings were the result of physical contact with each other and the surfaces of the beaker. In support of this hypothesis. beakers as well as samples were often observed to be cracked. The dullness of the tested specimens is likewise thought to be due to specimen- specimen and specimen-beaker contact. In summary, it is Objective: Procedure: Results: 152 felt that although there is finite dissolving of quartz by the concentrated potassium hydroxide solution. strengths of 80-20 and below do not produce appreciable damage over periods of up to six hours of boiling. EXPERIMENT 7 .KOH BOILING - SAND To determine the effect of boiling KOH solutions on sand grains by studying the percent weight loss and surface textures. Two HCl treated (2:5 carbonate removed) samples of Indian River sand were placed in 80-20 and 90-10 KOH solutions and boiled for six hours. The testing procedure was identical to experiment 6. Indian River sand was chosen because of its fresh texture (no frosting, few stiration marks, etc.). A graph of percent weight loss versus boiling time is presented in figum326. These percent weight loss values are subject to the same conditions as described in EXperiment 6. Comparison of pretest and post-test sand grains revealed no frosting, stirations, cracking, or other similar effects. The lack of surface markings was probably due to the small mass of the individual grains - thereby reducing the force of collision with the beaker and other grains. It is concluded that if the sand grains have been partially dissolved by the XOR solution, the percentage loss is not quantitatively Objective: Procedure: Results: Objective: Procedure: 153 significant. The surface textures are unaffected by ‘ the KOR solutions tested. EXPERIMENT 8 KOH STANDING - QDARTZ To determine the long term effect of room temperature potassium hydroxide solutions on quartz crystals. The preparation procedure was identical to that used in experiment 6. Twenty-four new quartz crystals were used in solution strengths of 60-40, 70-30, 80-20, 90-10, and 95-5. Test time was two months. In all cases the percent weight loss was less than 0.053. Inspection of the post-test specimens revealed that the surface textures were unaltered during the period of testing. EXPERIKENT 9 KOH TIiE DURATION To determine the time required for 90-10 and 80-20 strength potassium hydroxide solutions to remove sufficient chert cement from the sand grains to permit valid sieve analysis. Nine identical portions of the residue form the HCl-SnClZ treated sample #332 (coAI - new Richmond I-Iine) were boiled for time intervals of one, two and one-half, three, and six hours. Each sample was micrOSCOpically examined at the end of its respective time period. Results: Many 90-108 A10 80-20: Objective: Procedure: 154 A data table is presented below. Aggregation Some Few None B10 C10 D10 A20 B20 C20 220 Samples A were tested for one hour; samples B, for two and one-half; etc. Sample D20 (boiled in 80-20 KOH solution for six hours) contained no aggregates while the individual quartz grains were found to be essentially free of the chert cement. Samples D10 and 020 were found to contain a few aggregates and a small amount of chert cement. EXPERIMENT 10 H01 and KOH - SAND To determine the effect of the entire disaggregation process, HCl-SnClZ and 80-20 K08 boiling solution, on sand grains using roundness, sphericity, and sieve analysis as criteria. Roundness and sphericity measurements were made on Indian River Beach and Ferndale sands prior to being placed in concentrated hydrochloric acid for 30 days. At the end of 30 days samples were washed, dried, and measured for roundness and sphericity. Samples were then placed in 80-20.solutions of boiling K03 for six hours, at which time samples were washed, dried, and Results: 155 measured again. Roundness and sphericity measurements were made by mounting 300 or more grains on a slide, projecting on a screen, and tracing at a magnification ' of approximately 30X. The roundness equation used was R = §_£§llfll : where r1 is the radius of the individual corners; R, the radius of the maximum inscribed circle: and N, the number of corners measured. The sphericity equation used was S = R/ch where R is again the maximum inscribed circle: and R0, the minimum circumscribed circle. Measurements were made with a celluloid scribed in millimeters. Sieve analyses were made on the Indian River Beach and Ferndale sands before and after boiling in the XOR solution. A set of four-inch diameter Tyler sieves of meshes 10, 20, #0, 60, 80, 100, 120, 150, and 200 were used. Samples were sieved in a Tyler Automatic Ro-Tap shaker for 15 minutes. Below is presented a table of the test results. It is obvious that all the percent changes are well within the error of measurement. 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