Geometry and Origin of Oolite Bodies in the Ste

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Geometry and Origin of Oolite Bodies in the Ste. Genevieve Limestone (Mississippian) in the Illinois Basin

BULLETIN 48

STATE OFINDIANA DEPARTMENT OF NATURAL RESOURCES GEOLOGICAL SURVEY SCIENTIFIC AND TECHNICAL STAFF OF THE GEOLOGICAL SURVEY JOHN B. PATTON, State Geologist MAURICE E. BIGGS, Assistant State Geologist MARY BETH FOX, Mineral Statistician

COAL SECTION GEOPHYSICS SECTION CHARLES E. WIER, Geologist and Head MAURICE E. BIGGS, Geophysicist and HAROLD C. HUTCHISON, Geologist Head RICHARD L. POWELL, Geologist (on leave) ROBERT F. BLAKELY, Geophysicist VANCE P. WIRAM, Geologist JOSEPH F. WHALEY, Geophysicist MARVIN T. IVERSON, Geological Assistant CLARENCE C. HASKINS, Driller JOHN R. HELMS, Geophysical Assistant DRAFTING AND PHOTOGRAPHY SECTION WILLIAM H. MORAN, Chief Draftsman and Head INDUSTRIAL MINERALS SECTION RICHARD T. HILL, Geological Draftsman DONALD D. CARR, Geologist and Head ROBERT E. JUDAH, Geological Artist- CURTIS H. AULT, Geologist Draftsman GEORGE S. AUSTIN, Geologist ROGER L. PURCELL, Senior Geological MICHAEL C. MOORE, Geologist Draftsman GEORGE R. RINGER, Photographer EDUCATIONAL SERVICES SECTION PETROLEUM SECTION R. DEE RARICK, Geologist and Head T. A. DAWSON, Geologist and Head LEROY E. BECKER, Geologist GEOCHEMISTRY SECTION G. L. CARPENTER, Geologist R. K. LEININGER, Geochemist and Head ANDREW J. HREHA. Geologist LOUIS V. MILLER, Coal Chemist STANLEY J. KELLER, Geologist MARGARET V. GOLDE, Instrumental Ana- DAN M. SULLIVAN, Geologist lyst JAMES T. CAZEE, Geological Assistant ALFRED E. WHITE, Geochemical Assistant WILLIAM E. HAMM, Geological Assistant GEOLOGY SECTION JAMES F. THRASHER, Geological ROBERT H. SHAVER, Paleontologist and Assistant Head HENRY H. GRAY, Head Stratigrapher N. K. BLEUER, Glacial Geologist PUBLICATIONS SECTION EDWIN J. HARTKE, Environmental Geologist GERALD S. WOODARD, Editor and Head JOHN R. HILL, Glacial Geologist DONNA C. SCHULTZ, Sales and Records CARL B. REXROAD, Paleontologist Clerk

FRONT COVER: Slightly etched polished section of Ste. Genevieve oolitic limestone showing ooliths in a matrix of sparry calcite. Geometry and Origin of Oolite Bodies in the Ste. Genevieve Limestone (Mississippian) in the Illinois Basin

By DONALD D. CARR

DEPARTMENT OF NATURAL RESOURCES GEOLOGICAL SURVEY BULLETIN 48

PRINTED BY AUTHORITY OF THE STATE OF INDIANA BLOOMINGTON, INDIANA: 1973 STATE OF INDIANA Otis R. Bowen, Governor DEPARTMENT OF NATURAL RESOURCES Joseph D. Cloud, Director GEOLOGICAL SURVEY John B. Patton, State Geologist

For sale by Geological Survey, Bloomington, Ind. 47401 Price $1.75 Contents Abstract / 1 Introduction / 2 Previous work / 3 Acknowledgments / 3 Geologic setting / 4 Illinois Basin during Mississippian Period / 4 Stratigraphy of Ste. Genevieve and Paoli Limestones / 6 Oolite body near Orleans, Indiana / 10 Associated lithologies / 12 Skeletal (bryozoan) limestone lithology / 14 Pellet-mud carbonate lithology / 14 Impure limestone lithology / 17 The oolite body / 21 Geometry / 21 Petrography / 21 Sedimentary structures / 26 Chemical properties / 29 Physical properties / 31 Interpretation of environment / 33 Paleocurrents / 33 Methods / 33 Results / 34 Interpretation / 40 Basin setting / 46 Comparison of oolite body near Orleans with others / 47 Geometry / 47 Texture / 55 Main events in deposition / 61 Oolite body prediction / 63 Summary / 66 Geologic aspects / 66 Chemical and physical aspects / 68 Literature cited/ / 68 Contents Appendix A: Locations of cores used in the study of the oolite body near Orleans, Ind. / 75 Appendix B: Locations of well-exposed crossbedding in the Ste. Genevieve Limestone in the Illinois Basin / 77 Appendix C: Oolitic carbonate rocks used to study texture / 79 Illustrations Figure 1 Map of Indiana and neighboring states showing locations of principal geologic features in study area / 5 2 Chart showing Mississippian stratigraphic relationships in Illinois Basin / 6 3 Isopach map of Indiana and neighboring states showing thickness of Ste. Genevieve and Paoli Limestones (Renault Limestone and Girkin Formation) in Illinois Basin / 7 4 Diagram showing proportions of rock and limestone types in Paoli and Ste. Genevieve Limestones along eastern outcrop of Illinois Basin in south-central Indiana / 8 5 Diagram showing core holes along outcrop of Blue River River Group in Indiana and position of oolitic limestones and statistical moments / 9 6 Index map showing distribution of Mississippian rocks near Orleans, Ind. / 11 7 Diagram showing oolitic limestone and associated lithologies exposed in Radclif f, Inc., quarry near Orleans / 12 8 Photomicrographs of skeletal (bryozoan) limestone lithology of Ste. Genevieve Limestone / 13 9 Photomicrographs of pellet-mud carbonate lithology of Ste. Genevieve Limestone / 15 10 Photomicrographs of impure limestone lithology of Ste. Genevieve Limestone / 18 Illustrations Figure 11 Sedimentary structures in the impure carbonate lithology of Ste. Genevieve Limestone / 19 12 Isopach map showing thickness of Ste. Genevieve oolitic limestone lithology near Orleans / 20 13 Oolitic limestone and associated lithologies along the south face of Radcliff, Inc., quarry / 22 14 Diagrammatic section and vertical profiles showing mean grain size, sorting, and type of limestone in Ste. Gene- vieve oolite body near Orleans / 23 15 Photomicrographs of oolitic limestone lithology of Ste. Genevieve Limestone / 25 16 Map of crossbedding measurements in oolitic limestone lithology of Ste. Genevieve Limestone in Radcliff, Inc., quarry / 26 17 Diagram showing vertical profile of crossbedding orientation in oolitic limestone lithology of Ste. Genevieve Limestone, southeast wall of Radcliff, Inc., quarry / 27 18 Diagrammatic section and vertical profiles showing variation of bulk specific gravity and absorption in Ste. Genevieve oolite body near Orleans / 32 19 Sketches of crossbedding in Ste. Genevieve Limestone / 35 20 Histogram and plot on logarithmic probability paper of observed thickness of crossbeds in Paoli and Ste. Genevieve Limestones (or equivalent) in Illinois Basin / 36 21 Histogram and plot on logarithmic probability paper of angle of inclination of foresets in Ste. Genevieve and Paoli Limestones (or equivalent) in Illinois Basin / 37 22 Index map showing locations of detailed maps of crossbedding in Ste. Genevieve and Paoli Limestones (or equivalent) in Illinois Basin / 38 Illustrations Figure 23 Map showing crossbedding directions in Ste. Genevieve and Paoli Limestones in Indiana and north-central Kentucky / 39 24 Map showing crossbedding directions in Ste. Genevieve Limestone and Girkin Formation (or Renault Lime- stone) in southern Illinois and southern Kentucky / 40 25 Map showing crossbedding directions in Ste. Genevieve Limestone in southwestern Illinois and eastern Mis- souri / 41 26 Map showing crossbedding directions in Ste. Genevieve and Paoli Limestones (or equivalent), summarized by sampling interval, in Illinois Basin / 42 27 Current roses and vector means of crossbedding in sandstones of Chesterian Series and in Paoli and Ste. Genevieve Limestones in Illinois Basin and Salem Limestone in eastern part of Illinois Basin / 43 28 Histograms of variance of crossbedding in sandstones of Pocono Formation (Mississippian), Dakota Group (Cretaceous), and Mansfield Formation (Pennsyl- vanian) and in Salem and Ste. Genevieve Limestones at outcrops where 15 or more measurements were made / 44 29 Diagram showing vertical profiles of crossbedding orientation in Ste. Genevieve Limestone / 45 30 Schematic representation of electric log and stratigraphic column showing position of McClosky porosity zones in Ste. Genevieve Limestone in Illinois Basin / 48 31 A, Isopach map of McClosky C porosity zone (oolitic limestone of Ste. Genevieve Limestone), Spencer Field, Posey County, Ind. B, Cross section of porosity zone / 49 Illustrations Figure 32 A, Isopach map of McClosky B porosity zone (oolitic limestone of Ste. Genevieve Limestone), North Zion Field, Henderson County, Ky. B, Cross section of porosity zone / 5 1 33 A, Isopach map of McClosky C porosity zone (oolitic limestone of Ste. Genevieve Limestone), Martin Field, Vanderburgh County, Ind. B, Cross section of porosity zone / 52 34 Histograms of mean grain size and sorting of ancient and modern carbonate oolitic sands / 56 35 Data from figure 34 A, B, and C plotted on logarithmic probability paper to show close approach to straight- line fit / 57 36 Plot of mean grain size versus sorting of ancient and modern carbonate oolitic sands / 60 Tables Table 1 Attributes of Ste. Genevieve oolite body near Orleans / 28 2 Chemical analyses of samples from Ste. Genevieve oolitic limestone lithology, Radcliff, Inc., quarry / 30 3 Strontium content of Ste. Genevieve oolitic limestone near Orleans (A) and Ste. Genevieve and Paoli limestones from Indiana Geological Survey drill hole 150 (B) / 31 4 Distribution of class intervals of crossbedding in Paoli and Ste. Genevieve Limestones (and equivalent) at 147 outcrops in Illinois Basin / 34 5 Comparison of attributes of oolite body near Orleans with modern marine sand belt in Bahamas / 47 6 Comparison of size of ancient and modern oolite bodies / 54 Tables Table 7 Comparison of grain size and sorting of some ancient and modern oolites / 58 Geometry and Origin of Oolite Bodies in the Ste. Genevieve Limestone (Mississippian) in the Illinois Basin

By DONALD D. CARR

Abstract Oolitic limestones constitute 22 percent of the Ste. Genevieve and Paoli Lime- stones (Mississippian) in seven cores equally spaced along the length of outcrop in southern Indiana; which lies on the eastern margin of the Illinois Basin. Similar oolitic limestones are found in equivalent stratigraphic formations in Kentucky and Illinois. Isopach mapping and analysis of 889 crossbedding measurements in the Illinois Basin indicate that paleoslope during deposition of these oolitic limestones was to the southwest, as it was earlier during deposition of carbonate sands of the Salem Limestone (Mississippian) and later during deposition of most of the late Paleozoic sands. An elongate lenticular Ste. Genevieve oolite body about 2 miles (3.2 km) wide, more than 4 miles (6.4 km) long, and about 25 feet (7.6 m) thick, partly exposed in a quarry near Orleans, Ind., has been found to be oriented almost perpendicular to the paleoslope of the basin, as determined by isopach mapping and measurement of crossbedding. Synthesis of the environment of deposition based on lithologic relationships, geometry, and internal features indicates that the oolite body is a marine sand belt that has some features much like those forming today on the west edge of the Great Bahama Bank. Other Ste. Genevieve oolite bodies in the subsurface of the Illinois Basin, which are similar in shape and size to the oolite body at Orleans, are believed to have had a similar origin. Although predicting the location of oolite bodies of this type in the Illinois Basin is difficult, isopach mapping and crossbedding analysis may help in determining the orientation of these bodies near the outcrop. Based on 81 thin sections from the oolitic limestone lithology near Orleans, the average grain size is 1.47ø (.36 mm) and the average sorting is 0.90ø. Best sorting is 0.50ø, which is similar to that reported for other ancient oolitic limestones, but which is somewhat poorer than that found in modern oolites. Grain distribution for the oolite body at Orleans is generally negatively skewed near the base of the body, but in the upper part ranges from about 0 to +O.50. The oolitic limestone at Orleans is suited for many industrial purposes 1 2 GEOMETRY AND ORIGIN OF OOLITE BODIES because its calcium and magnesium carbonate content averages more than 99 percent by weight. The apparent porosity of the center part of the oolite body is 3.38 percent, but the porosity of the exterior rind, averaging 1.25 percent, is much less. The relatively high apparent-porosity zone in the center part of the oolite body appears to be similar to porosity zones in oolite bodies that are found in the subsurface of the Illinois Basin and that are excellent reservoirs for petroleum.

Introduction Ancient quartzose and carbonate sand bodies share many similar characteristics but have received unequal attention in geologic literature. These two kinds of sand bodies differ in the origin and composition of individual grains, but they have much in common in shape, internal structure, and texture. One reason that so little has been published about the shapes of carbonate sand bodies in ancient rocks is that most of the different textural types of limestone are difficult to distinguish and map, both in outcrop and the subsurface. Quartzose sand bodies are more easily distinguished in ancient rocks than carbonate sand bodies because quartzose sands can be easily recognized in samples and electric logs. Studies that have given attention to the three-dimensional shape of carbonate bodies have generally been concerned with bioherms in places where deposition is greatly influenced by organic growth. Some oolitic carbonate sand bodies are suited for morphologic study because they can be easily distinguished from other textural limestone types. The Ste. Genevieve Limestone of middle Mississip- pian (Valmeyeran) age was specifically selected for this study because its oolitic limestones are exposed and easily distinguished at many places in the Illinois Basin. In addition, a Ste. Genevieve oolite body is well exposed in a quarry near Orleans in south-central Indiana, and sufficient cores have been taken near the quarry to allow detailed study. Ste. Genevieve oolitic limestones of the Illinois Basin are economically important. Many are of high chemical purity and can be exploited as high-calcium limestone, and subsurface units of Ste. Genevieve oolitic limestone, locally called the McClosky Sand or Lime, are prolific oil reservoirs. ACKNOWLEDGMENTS 3 Previous Work Published literature showing the geometry of ancient carbonate sand bodies and comparing them with modern analogs is scarce. Rich (1948) was among the first to make a morphologic analysis by comparing the shape of lenticular sand bodies in the Clinton Group of central Ohio with carbonate sand bodies of the Bahamian Banks. A year later, Rittenhouse (1949), who studied the subsurface distribution of oolitic limestones in the Greenbrier Formation of West Virginia and Ohio, concluded that these oolite bodies formed on a shallow-water marine shelf or in a shallow epicontinental sea. Apparently Connolly (1949) was the first to attempt mapping an ancient oolite body in the subsurface. In his study of the Passport oil pool in southeastern Illinois he (p. 30-31) used mainly structure and slice maps to show the shape and orientation of two oolite bodies in the Ste. Genevieve Limestone, and he drew attention to similarities in composition, shape, and size of these ancient oolite bodies and of modern oolite bodies forming in the Bahamas. In a similar study Truitt (1950) used isopach and structure maps to determine the geometry of part of two Ste. Genevieve oolite bodies in the Spencer oil pool in southwestern Indiana. About 10 years later Whiting (1959) mapped the thickness of an arenaceous oolitic limestone, the Spar Mountain Sandstone Member of the Ste. Gene- vieve Limestone, in east-central Illinois and interpreted its environment of deposition as also being similar to that of the modern Bahamian Banks. Leith (1949, p. 152) observed that Ste. Genevieve oolitic limestones in Indiana consist of discontinuous lenticular bodies of small lateral extent, and Malott (1952, p. 8) commented on the variable thickness of Ste. Genevieve oolitic beds. Kissling (1967, p. 241) interpreted Paoli oolitic limestones in Indiana as elongate bodies 0.5 to 2 miles (0.8 to 3.2 km) wide and 10 to 20 miles (16.1 to 32.3 km) long. He concluded that these bodies had formed in the sublittoral zone in which the long axes of the bodies were parallel to the ancient shoreline. Acknowledgments This report was modified from a Ph. D. dissertation conducted at 4 GEOMETRY AND ORIGIN OF OOLITE BODIES Indiana University under the supervision of Paul E. Potter. Law- rence F. Rooney, Flathead Valley Community College, introduced me to the oolite body near Orleans, Ind., where the detailed study was made, helped with the field mapping, and provided thoughtful advice throughout the study. Special information and help were provided by J. W. Baxter and Elwood Atherton, of the Illinois Geo- logical Survey; Preston McGrain and G. R. Dever, Jr., of the Ken- tucky Geological Survey; P. W. Richards, R. D. Trace, E. G. Sable, and R. C. Kepferle, of the U.S. Geological Survey; J. R. Dodd, Indiana University; and C. H. Ault, R. F. Blakely, and R. K. Leininger, of the Indiana Geological Survey. Critical reviews were made by Gordon Rittenhouse, Shell Oil Co., and by Edward McFarlan, Jr., H. H. Beaver, and D. G. Bebout, Esso Production Research Co. Samples of oolitic carbonate rocks were supplied by C. H. Ault, D. F. Branagan, A. H. Coogan, G. H. Goudarzi, W. K. Hamblin, D. E. Hattin, T. E. Hendrix, R. K. Hogberg, C. F. Kahle, George Kneass, W. R. Lowell, J. A. Martin, J. B. Patton, R. D. Perkins, P. E. Potter, Rajka Radiocic, J. C. Riggi, P. U. Rodda, T. H. Rogers, L. F. Rooney, Hans-Ulrich Schmicke, Randolph Stone, V. Subraman- yam, L. M. Toohey C. J. Vitaliano, and G. V. Wood. Edward G. Purdy, Esso Exploration, Inc., kindly supplied unpublished textural data on oolitic sands from the Bahamas. Wayne R. Lowell, the Monon Railroad, and the Indiana Geological Survey contributed cores that were necessary for this study. A Doctoral Student Grant in Aid of Research at Indiana University helped provide travel expenses for fieldwork in Illinois, Kentucky, and Missouri. I extend thanks to each of these individuals and institutions. Geologic Setting ILLINOIS BASIN DURING MISSISSIPPIAN PERIOD Subsidence of the Illinois Basin during early Mississippian time resulted in a structural basin trending northwestward and southeast- ward with the Ozark Dome to the southwest and the Cincinnati Arch to the east and northeast (fig. 1). Black shales and siltstones of the Borden Group were deposited in the central and eastern parts of the basin, cherty limestones and calcareous siltstones of the Fort Payne Chert in the southern part, and cherty fossiliferous limestones and dolomites and calcareous shales of the Fern Glen, Burlington, and Keokuk Limestones in the western and northern parts. GEOLOGIC SETTING 5

Figure 1. Map of Indiana and neighboring states showing locations of principal geologic features in study area.

During middle Mississippian time the seas became shallower, and deposition consisted mainly of carbonate sediments. In the eastern part of the basin in Indiana, the middle Mississippian carbonate section, consisting of the Harrodsburg, Salem, St. Louis, Ste. Gene- vieve, and Paoli Limestones, is as much as 600 feet (183 m) thick, but these units thicken to the southern border of the basin in Ken- tucky, where they are as much as 2,000 feet (610 m) thick. During early St. Louis time evaporites were deposited, and as a result, as much as 75 feet (23 m) of anhydrite and gypsum in Indiana and lesser amounts in Illinois and Kentucky were formed. During late Mississippian time alternating series of shales, limestones, and sandstones, known collectively as the Chesterian Series, filled the basin. Chesterian limestones are thin but extend over large areas of the basin. The shales and sandstones are more variable in lateral continuity than the limestones, which reflects their alluvial- deltaic origin. GEOMETRY AND ORIGIN OF OOLITE BODIES

EASTERN ILLINOIS AND INDIANA SOUTH-CENTRAL INDIANA NORTHERN KENTUCKY GROUP OUTCROP KENTUCKY SUBSURFACE OUTCROP SUBSURFACE

Bethel Sandstone Bethel Sandstone Bethel Formation

Upper port of Girkin Formation Renault Limestone

Paoli Limestone Benoist Sand Renault Formation

Lower port of Renault Limestone

Aux Vases Aux Vases Sandstone Formation

/ Ste. Genevieve Ste. Genevieve McClosky Sand McClosky Sand Limestone Limestone Ste. Genevieve Ste. Genevieve Limestone LImestone

I I

St. Louis St. Louis St. Louis St. Louis Limestone Limestone Limestone Limestone I I Figure 2. Chart showing Mississippian stratigraphic relationships in Illinois Basin.

STRATIGRAPHY OF STE. GENEVIEVE AND PAOLI LIMESTONES The Ste. Genevieve and Paoli Limestones, which form the upper part of the thick middle Mississippian carbonate section, are the upper part of the Blue River Group (fig. 2). Historically, these two limestones have been separated on the basis of a paleontologic criterion. The Valmeyeran (Ste. Genevieve)-Chesterian (Paoli) boundary has been picked at the Platycrinites penicillus-Talarocrinus boundary, where a crinoid-bearing facies is present (Swann, 1963, p. 32-33). These two formations have been grouped together in this study because they are lithologically similar and because they form a con- venient economic unit. They are generally quarried together in Indiana and north-central Kentucky. The Ste. Genevieve and Paoli Limestones range in thickness from a thin edge along the northern limits of the Illinois Basin in Illinois and Indiana to about 400 feet (122 m) in the southern part of the basin in Kentucky (fig. 3). An exact equivalence of formations can- GEOLOGIC SETTING 8 GEOMETRY AND ORIGIN OF OOLITE BODIES not be made, however, because the upper part of the carbonate section, called the Girkin Formation along the south-central Ken- tucky outcrop, appears to be equivalent to the Beech Creek Lime- stone of Indiana. Thus the upper part of the Girkin in Kentucky probably includes the elastic and carbonate sections of the West Baden Group and part of the Stephensport Group of Indiana (Swann, 1963, p. 50). The Ste. Genevieve and Paoli Limestones, like most of the middle Mississippian carbonate formations, thicken irregularly basinward from the outcrop in Indiana and north-central Kentucky.

LIMESTONE

Figure 4. Diagram showing proportions of rock and limestone types in Paoli and Ste. Genevieve Limestones along eastern outcrop of Illinois Basin in south-central Indiana. Data from 841 feet of core from seven Indiana Geological Survey drill holes. Along the eastern outcrop of the basin the Ste. Genevieve and Paoli Limestones consist mainly of light grayish-brown fine-grained micritic limestones and of almost equal but smaller percentages of oolitic and skeletal limestones (fig. 4). Clastic sediments consisting of sandstone and shale amount to only 7 percent of the total section, and chert amounts to less than 1 percent. GEOLOGIC SETTING 10 GEOMETRY AND ORIGIN OF OOLITE BODIES Although oolitic limestones appear irregularly from top to bottom of the Paoli and Ste. Genevieve, most of them appear in the upper half of the section. The relative center of gravity of the oolitic limestones, determined (Krumbein and Libby, 1957) for seven cores evenly spaced along the eastern outcrop of the Ste. Genevieve and Paoli, was found to lie from 35 to 47 percent of the distance from the top of the section (fig. 5). The spread of the oolitic limestones about the center of gravity was variable; one standard deviation ranged from plus or minus 13 to 60 feet (4 to 18 m) (fig. 5). Oolite Body Near Orleans, Indiana A detailed study of a single oolite body in the Ste. Genevieve was made to determine its characteristics and to compare it with other ancient and modern oolite bodies. This study was undertaken specifically to determine (1) lithologic relationships, (2) geometry (three- dimensional shape and orientation, (3) textural relationships, (4) depositional environment, (5) variation in chemical properties, and (6) variation in physical properties. The oolite body selected for study is well exposed in more than 2,000 feet (610 m) of face at the Radcliff, Inc., quarry near Orleans, Orange County, Ind. The study area lies near the west edge of the Mitchell Plain, a limestone plateau or upland characterized by karst features, such as sinkholes, sinking streams, underground drainage, and caverns. A few outliers of sandstone and shale of the West Baden Group cap the highest hills (fig. 6). The ragged Chesterian escarpment and Crawford Upland lie a few miles to the west. Twenty-one cores taken near the quarry were used in the study (Appendix A). Outcrops and abandoned quarries, although few, provided additional data. A total of 1,295 feet (395 m) of core and quarry section and 785 feet (239 m) of well cuttings was examined. The oolite body was examined in detail by sampling at about l-foot (30.5-cm) intervals along five vertical profiles through the oolite body along the quarry face and in three cores. One hundred and five thin sections were studied. In addition to the samples used in the vertical profiles, 70 samples taken from other cores were tested physically. The oolite body in the quarry was mapped by plane table and alidade. Compositional and textural data were determined by thin-section OOLITE BODY NEAR ORLEANS, INDIANA

IYh INDIANA ,/

EXPLANATION

West Baden Group

0 2 Miles I t 1’1 0 2 Km

Figure 6. Index map showing distribution of Mississippian rocks near Orleans, Ind. analysis based on 200 point counts. Mean grain size and sorting values from thin-section analysis have been converted to sieving equivalents according to the method outlined by Friedman (1962a, figs. 1 and 5); however, skewness values are reported as calculated directly from thin section. The program used for computing moment measures was similar to one described by Pierce and Good (1966). Superficial ooliths have been defined several different ways, but for this study they were considered to be oolitic grains with accre- 12 GEOMETRY AND ORIGIN OF OOLITE BODIES tionary coats less than 0.05 mm thick. Using a coating thickness of fixed size is the easiest and quickest way to separate true ooliths from superficial ooliths in thin section, and this way requires less subjective judgment in classifying ooliths. Spectrochemical determinations of calcium, magnesium, aluminum, iron, titanium, manganese, sulfur, and phosphorus were made with a Jarrell-Ash JA-70-15e 21 -foot (W)-grating spectrograph. Silica and carbon dioxide determinations were made gravimetrically. Bulk specific gravity and absorption testing followed procedures outlined by the American a Society for Testing and Materials in C127-59 C127-59 (1968).

Feet EXPLANATION 20 f$$j 15 Impure limestone 10 pjg 5 Oolitic limestone

0 Ezl Pellet-mud carbonate Lost River 1 Chert Bed m Skeletal limestone

Figure 7. Diagram showing oolitic limestone and associated lithologies exposed in Radcliff, Inc., quarry near Orleans.

ASSOCIATED LITHOLOGIES LITHOLOGIES Four principal carbonate lithologies are associated with the oolite body near Orleans (fig. 7). In ascending order from the bottom these are: skeletal (bryozoan) limestone lithology; pellet-mud carbonate lithology; oolitic limestone lithology; and impure limestone lithology. To maintain continuity, these lithologies are discussed in ascending order except for the oolitic limestone lithology, which is discussed in more detail following the discussion of the other associated lithologies. OOLITE BODY NEAR ORLEANS, lNDlANA 13

Figure 8. Photomicrographs of skeletal (bryozoan) limestone lithology of Ste. Genevieve Limestone. A, Photomicrograph of skeletal (bryozoan) limestone. B, Photomicrograph of microcrystalline chert replacing skeletal fragments in the skeletal (bryozoan) limestone lithology (Lost River Chert Bed). Large skeletal fragment has not been completely silicified. 14 GEOMETRY AND ORIGIN OF OOLITE BODIES

SKELETAL (BRYOZOAN) LIMESTONE LITHOLOGY: This lithology consists mainly of limestones that are light brownish gray (Munsell color 5YR6/1), coarse grained, and medium bedded. The unit averages about 10 feet (3 m) in thickness and is laterally persistent throughout the study area. Bedding is indistinct, but stylolites occur about every 0.5 foot (15 cm). The limestones contain 42 to 61 percent skeletal fragments, 17 to 45 percent pellets and lumps, and 7 to 13 percent sparry calcite cement (fig. 8A). Coated grains are commonly found admixed near the upper bounding surface of the unit. Fenestrate bryozoans constitute about 80 percent of the skeletal fragments, and the remaining fragments, in order of decreasing abundance, are ramose bryozoans, echinoderms, Endothyra, gastropods, and brachiopods. The Lost River Chert Bed lies near the middle of the skeletal (bryozoan) limestone lithology and forms a persistent marker bed. It is about 2.5 feet (0.8 m) thick near the quarry and thins to a few inches about 2 miles (3.2 km) basinward to the west. It consists of 30 to 60 percent chert as white or light bluish-gray nodules and discontinuous thin beds. Conspicuous skeletal fragments throughout the chert indicate that chert has replaced carbonate (fig. 8B).

PELLET-MUD CARBONATE LITHOLOGY: This lithology is principally at the bottom of the oolite body, but pellet-micritic limestones are also found as laminae and beds within the oolitic limestone lithology. It is characteristically medium brownish gray (7YR5/1) to brownish gray (5YR5/ 1) to brownish black (5YR2/ 1) and ranges from 0 to about 7 feet (2.1 m) in thickness. In places it is replaced by laminae or very thin beds of moderate yellowish-brown (10YR5/4) calcareous shale. About 60 percent of the lithology consists of pellet-micritic limestone (fig. 9A), and most of the remaining part is very finely crystalline dolomite (fig. 9B). The pellet-micritic limestone contains as much as 10 percent coated grains and skeletal material, mainly bryozoan fragments and Endothyra, 2 to 15 percent coarse quartz silt, and 1 to 5 percent fine silt and clay-size insoluble residues. Small pods of skeletal-micritic limestone are uncommon, but argillaceous laminae are common throughout the unit, and small pods of oolites are common near the interface of the pellet-mud carbonate lithology and the oolitic limestone lithology. The very finely crystalline dolomite is generally thin to medium OOLITE BODY NEAR ORLEANS, INDIANA 15

Figure 9. Photomicrographs of pellet-mud carbonate lithology of Ste. Genevieve Limestone. A. Photomicrograph of pellet-micritic limestone. B, Photomicro- graph of microcrystalline dolomite. Skeletal fragment has not been completely dolomitized. 16 GEOMETRY AND ORIGIN OF OOLITE BODIES bedded with argillaceous laminae. Nodules of pellet-micritic limestone as much as 1.5 feet (0.5 m) thick are commonly found in sharp contact with the dolomite and may be recognized by a lighter color. Skeletal material and ooliths larger than 0.125 mm in the dolomite generally are not dolomitized. The dolomite has 2 to 8 percent insoluble residue, which appears uniformly distributed. As much as one-half of the residue is fine silt and clay and the remainder is coarse quartz silt. The residues from the dolomitic rocks differ from the residues from the limestones in that they contain a dark-gray organic- rich sludge. The organic material, which causes the dark color of the dolomitic rocks, appears to be largely confined to pore spaces and thus is more abundant in the higher porosity dolomites. Dark-gray chert nodules as much as 0.2 foot (6 cm) in diameter are found in places in this unit. Burrowing is common in the pellet-mud lithology, especially in the bottom part of the unit. The burrows consist of irregularly oriented cylindrical tubes that range from 0.1 to 0.3 mm in diameter and that are as much as a few centimeters long. The burrows are filled with sparry calcite and are conspicuous in the field because of their light color against the darker color of the pellet-micrite matrix. Deformational structures are common in places where the pellet- mud lithology has been deformed and has intruded upward into the oolite body, although in some places it appears that the oolite body protrudes downward into the pellet-mud lithology. In the former places the pellet-mud intrusives appear as rounded elongate pods, which may be as much as 3 feet (0.9 m) wide and 30 feet (9 m) long and aligned subparallel to the base of the oolite body. The pods may intrude as much as 4 feet (1.2 m) into the oolite body and may or may not be connected with the pellet-mud lithology below. In the latter places downward protuberances of the oolite body into the pellet-mud lithology may extend as much as 0.5 foot (15 cm) and look like large-scale load casts. Oolitic grains are commonly admixed in the pellet-micritic limestone along its bounding surface. These deformational structures appear to have resulted from the diapiric intrusion of the underlying fine-grained pellet muds into the ooliticsand. This intrusion occurred prior to lithification and in response to loading pressures. Such deformational structures are common in terrigeneous sediments (Potter and Pettijohn, 1963, p. 143-172), especially where sands overlie finer grained muds. All OOLlTE BODY NEAR ORLEANS, INDIANA 17 that is needed to generate this type of deformation is the unequal loading of a denser material, such as sand, on a fine-grained sediment, such as mud. As water is squeezed out of the mud because of pres- sure, it begins to flow principally upward into the overlying sand (McKee and Goldberg, 1969, p. 235). The genesis of these structures, although they are much smaller in scale, appears akin to that of the silt and clay mud lumps in the Mississippi bird-foot delta (Fisk, 1960, p. 48).

IMPURE LIMESTONE LITHOLOGY: Various rock types constitute the impure limestone lithology, any one of which may predominate in a particular area. The main rock types are limestones that are thin bedded, partly argillaceous, oolitic, skeletal, detrital, and pellet micritic. Mud-shale and sandstone constitute 5 to 15 percent of the impure limestone lithologic unit, which ranges from about 3 feet (0.9 m) to about 15 feet (4.6 m) in thickness. This unit has been called the Rosiclare Member of the Ste. Genevieve along the outcrop in south-central Indiana since 1952 (Malott, 1952, p. 8-9); Swann (1963, p. 83), however, believed that the unit had been misidentified and that it should have been called the Spar Mountain Sandstone Member. Insoluble residues are as much as 35 percent in this unit and appear evenly distributed throughout a stratum of rock. The high insoluble- residue content, which is far more than that found in the other facies, is one of the most distinguishing characteristics of the unit (fig. 1 OA). The residue consists of as much as 6 percent fine silt and clay, as much as 30 percent coarse quartz silt, and as much as 2 percent 0.35-mm quartz sand. The quartz sand is composed of angular to round grains. Some well-rounded quartz grains as large as 1 mm have been found, and some are the nuclei of ooliths (fig. 10B). Brecciation is common in the pellet and micritic limestones and less common in the skeletal and oolitic limestones of the impure limestone lithology. Discoidal pebbles and cobbles of micritic, skeletal, or oolitic limestone as much as 6 inches long are in a matrix of micritic limestone. Brownish-black sinuous laminae of micritic limestone that are interpreted as algal structures are commonly found in the micritic matrix (fig. 11A). The detrital fragments may occur either as sharp angular pieces or as rounded pebbles. Thin gray mud- shale partings commonly mark the top of the brecciated units. 18 GEOMETRY AND ORIGIN OF OOLITE BODIES

Figure 10. Photomicrographs of impure limestone lithology of Ste. Genevieve Limestone. A, Photomicrograph of impure limestone. Arrows point to very fine-grained quartz. B, Photomicrograph of oolitic-pellet limestone. Arrows point to quartz nuclei of ooliths. OOLITE BODY NEAR ORLEANS, INDlANA

Figure 11. Sedimentary structures in the impure carbonate lithology of Ste. Genevieve Limestone. A, Cores from impure limestone lithology. Note prob- able dark algal structures and limestone breccia in lower part of left core. B, Desiccation polygons in impure carbonate lithology in Radcliff, Inc., quarry. 20 GEOMETRY AND ORIGIN OF OOLITE BODIES

R. I W. R. I E.

13 16

LAWRENCE CO . -_7 -_ _ ‘Z\_I---A ORANGE CO l7-. -.

T. 3 N.

EXPLANATION

l Core location 0 Rotary drill hole 2 Active quarry r. 2 Inactive quarry ? ,5~ lsopach contour V. 0 I Mile t ’ ‘I’ ’ 0 IKm

Figure 12. Isopach map showing thickness of Ste. Genevieve oolitic limestone lithology near Orleans.

Desiccation polygons 0.6 to 1.0 foot (15 to 30 cm) in diameter are found in the brecciated limestones (fig. 11B) and are best seen in quarries where large areas have been stripped parallel to the bedding planes. Where best developed these polygons consist of grayish-orange (lOYR7/4) calcareous siltstone with shrinkage cracks filled with argillaceous micritic limestone. Burrow structures similar to, but not as abundant as, those in the pellet-mud lithology are present in the impure limestone facies. Crossbedding is similar in type and abundance to that of the OOLITE BODY NEAR ORLEANS, INDIANA 21 oolitic limestone lithology. The impure limestone lithology is not as well exposed, however, as the oolitic limestone lithology, so that quantitative comparison is difficult.

THE OOLITE BODY GEOMETRY: The oolite body extends north and south, and its thicker parts are oriented at about 30º northeastward and southwestward (fig. 12). Where mapped, it is about 2 miles (3.2 km) wide and more than 4 miles (6.4 km) long, but its length cannot be accurately determined because it extends beyond the control cores. Possibly the oolite body is only a portion of a larger ribbonlike sand body that continues north and south. Oolitic limestones lie in about the same stratigraphic position 8 miles (12.9 km) south in Indiana Geological Survey drill hole 150 and 7 miles (11.3 km) north in Indiana Geological Survey drill hole 153. In cross section the body appears to be lenticular, with an almost flat lower surface and a convex upward upper surface. It has a maximum measured thickness of 25 feet (7.6 m) and thins irregularly toward its margins. The basal surface of the oolite body exposed on the quarry face is remarkably flat, but the upper surface drops 11 feet (3.4 m) toward the northeast within 1,200 feet (366 m).

PETROGRAPHY: The oolitic limestone lithology is principally very light gray (N-8) to white (N-9), but toward the flank of the body in the northern part of the Radcliff, Inc., quarry, it grades to light brownish gray (5YR6/1).. The light-colored oolitic limestones in the quarry are easily distinguished from the darker adjacent units (fig. 13). The framework of a typical oolitic limestone consists of 60 percent ooliths, 15 percent superficial ooliths, 22 percent pellets and lumps, and 3 percent skeletal material; however, the basal part and flanks contain more pellets and lumps than the rest of the body (fig. 14). Uncoated skeletal material is most abundant in the basal part of the oolite body and decreases irregularly upward. Terrigenous material is virtually absent except for an occasional quartz or feldspar nuclei of an oolith. The average grain size of 81 samples from the oolitic limestone facies studied in thin section is 1.47ø (0.36 mm), which classes the limestone as medium grained . Grain size, averaging about 2.25ø (0.21 mm), is finer near the base of the oolite body because of the 22 GEOMETRY AND ORIGIN OF OOLITE BODIES

Figure 13. Oolitic limestone and associated lithologies along the south face of Radcliff, Inc., quarry. Note intrusion of pellet-mud lithology into oolitic limestone lithology in lower left comer. , increase in pellets derived from the subjacent pellet-mud carbonate lithology. A coarsening occurs upward in the body punctuated by laminae and thin beds containing coarse to very coarse skeletal fragments (fig. 14). Grains are poorly sorted near the base and along the western (basinward) flank of the oolite body and become moderately sorted upward (fig. 14). Mean sorting value of the 81 samples is 0.90ø, and skewness values for these samples range from -0.45 to +0.77. Grain distribution is generally negatively skewed near the base and flanks of the oolite body because of the increase in fine-grained pellets. In the middle and upper parts of the oolite body, skewness ranges generally from 0 to +0.50. In thin section the ooliths have a range of elongation from 0.70 to 0.85 (subequant to very equant) (Folk, 1965, p. 91) and a round- ness from 0.5 to 0.9 (Krumbein and Sloss, 1956, p. 81). The shape of these ooliths is similar to that of other Ste. Genevieve ooliths in the Illinois Basin, such as those shown by Shrode (1949, p. 118) from southern Illinois. The ooliths exhibit well-developed laminae, OOLITE BODY NEAR ORLEANS, INDIANA 23

:**:.*‘~ .~*~~~*::~: ** ~~~.~~~~~.~ 6 .*.:**. 5’ * ...... ‘.‘.“.‘.‘.‘. gL+ . . . ::.**. ..:’ -I- l .*. ;:-.. d . . *. z -,‘oo.‘.-.* ..**. 0.0 0. zi *.*...*.

s ‘..’0 * l J:. f 24 GEOMETRY AND ORIGIN OF OOLITE BODIES with both radial and concentric structure. Most nuclei are abraded skeletal fragments, pellets, or lumps. Elongate ooliths have coats which generally range from 0.15 to 0.20 mm in thickness on the side of the grains but from only 0.05 to 0.10 mm on the ends of the grains. Ooliths slightly deformed by compaction are common, but ooliths whose concentric coats have split off (Graf and Lamar, 1950, p. 2331) and ooliths that have interpenetrated and broken (Graf and Lamar, 1950, p. 2331; Radwanski, 1965, pls. 15-l9) are relatively uncommon. Cerebroid ooliths (Graf and Lamar, 1950, fig. 7; Carozzi, 1962) are rare, and extremely distorted ooliths (Carozzi, 1961) have not been found. The percentage of uncoated shell fragments in the oolite body at Orleans is low, generally less than 5 percent. Evidently the turbulent water currents that caused the growth of the ooliths were not favor- able to the development of a benthonic fauna. Vegetation had difficulty in anchoring in the constantly shifting oolitic sands, and animals found the environment inhospitable. A paucity of uncoated shell fragments probably is to be expected, for it has been reported in other ancient oolitic limestones (Playford and Lowry, 1966, p. 55-58; Bishop, 1968, p. 101; Balthaser, 1969, p. 204) and in modern oolitic marine sand belts in the Bahamas (Newell and others, 1959, p. 218; Purdy, 1964, p. 256). Oolitic limestone in the central part of the oolite body is more poorly cemented than that along the bounding surface or rind of the body. The outer 2 to 5 feet (0.6 to 1.5 m) of oolitic limestone typically contains 15 to 35 percent sparry calcite (.05 to .5 mm) cement that fills nearly all pores (fig. 15A). The center part of the oolite body contains 1 to 25 percent sparry calcite cement that occurs along grain-to-grain contacts and in interstices (fig. 15B). The grain-cement contact is generally sharp and shows little evidence of etching. Graf and Lamar (1950, p. 2336) explained the development of porosity in some Ste. Genevieve oolites in southern Illinois through a history of cementation and solution of calcite; they found that primary porosity is most common where the individual ooliths are bound by sparry calcite. The same type of porosity is found in the central part of the Orleans oolite body; however, along its exterior rind the pore spaces are almost wholly filled by sparry calcite. OOLITE BODY NEAR ORLEANS, INDIANA 25

Figure 15. Photomicrographs of oolitic limestone lithology of Ste. Genevieve Limestone. A, Photomicrograph of oolitic limestone from upper part of oolitic limestone lithology. Sparry calcite cement almost fills intergranular area. B, Photomicrograph of oolitic limestone from middle part of oolitic limestone lithology. Arrows point to intergranular porosity. Crossed nicols. 26 GEOMETRY AND ORIGIN OF OOLITE BODIES

EXPLANATION

O-33% 34-66% 67-100% Crossbedding direction and vector strength

Figure 16. Map of crossbedding measurements in oolitic limestone lithology of Ste. Genevieve Limestone in Radcliff, Inc., quarry. Current rose shows distribution and mean of 41 crossbedding measurements.

SEDIMENTARY STRUCTURES: Crossbedding in the oolitic limestone lithology of the Ste. Genevieve is moderately abundant but difficult to see on the fresh quarry face at the Radcliff, Inc., quarry. Cross- bedding can be seen there at a few places and is particularly well displayed on weathered surfaces in grikes. Planar crossbeds predominate over trough crossbeds in the oolitic limestone lithology, but OOLITE BODY NEAR ORLEANS, INDIANA 27 both are present. A map of azimuth direction of crossbeds shows a bimodal distribution, a northeast-southwest orientation, and a vector mean of 253” (fig. 16). A vertical profile of crossbedding orientation shows the pronounced alternation of current direction through about 180” (fig. 17). -

900 K?0= Y 360° Azimuth Figure 17. Diagram showing vertical profile of crossbedding orientation in oolitic limestone lithology of Ste. Genevieve Limestone, southeast wall of Radcliff, Inc., quarry. The maximum thickness of crossbedding in the oolitic limestone lithology at Orleans is 39 inches (99 cm), but most crossbeds range from 4 to 20 inches (10 to 5 1 cm) in thickness. These thicknesses are comparable to the crossbedding thicknesses of oolitic limestones 28 GEOMETRY AND ORIGIN OF OOLITE BODIES Table 1. Attributes of Ste. Genevieve oolite body near Orleans Geometry: Shape: Elongate lenticular body with an almost flat lower boundary surface and a convex upward upper surface. Dimensions: Length: more than 4 miles (6.4 km); width: about 2 miles (3.2 km); and thickness: about 25 feet (7.6 m). Orientation: Elongate north-south, almost parallel to inferred depositional strike. Position in basin: Elongate parallel to inferred shoreline on gentle slope. Internal characteristics: Grain size and distribution: Mean 1.47ø (.36 mm); sorting .90ø (average); skewness range -.45 to +.77. Positively skewed, mainly 0 to +.50 except near base, which is negatively skewed. Bedding: Crossbeds mainly 4 to 20 inches (10 to 51 cm), but some exceed 3 feet (0.9 m). Bedding indistinct in many places. Sedimentary structures: Crossbeds abundant in places. Planar crossbeds predominate over trough. Crossbedding azimuths are bimodally distributed with orientation of modes perpendicular to elongation of body. Ripple marks common but many indistinct. Intraformational conglomerate common near base. Pellet-micritic limestone in places intruded into base of oolite body. Constituents: Typical oolitic limestone framework contains 60 percent ooliths, 15 percent superficial ooliths, 22 percent pellets and lumps, and 3 percent skeletal grains. Sparry calcite cement ranges from 1 to 35 percent but is most abundant in limestones along bounding surface of body. Bounding lithologies: Four distinct lithologies recognized in ascending order: skeletal (bryozoan) limestone, pellet-mud carbonate, oolitic limestone, and impure limestone. Basal contact of oolitic limestone is almost flat. in the upper Mississippian rocks of the Cumberland Plateau, which were reported by Peterson (1962, p. 8) to range from 1 to 3 feet (0.3 to 0.9 m). Current ripples are present in the oolitic limestone lithology but are difficult to see on the fresh quarry face. They are most easily seen as stylolites that follow along the ripple surface. These stylolites probably began to form early in the diagenetic history of the rock as a result of inhomogeneity of grain texture or composition along the ripple surface. Megaripples in the oolitic limestones have gentle lee sides and generally range from 20 to 30 feet (6.1 to 9.1 m) in wave length. Amplitude of these ripples is as much as 3 feet (0.9 m). These megaripples probably correspond to ripples on oolite bodies in the Bahamas that have been described as “medium- or large-scale” (Ball, OOLITE BODY NEAR ORLEANS, INDIANA 29 1967, p. 560),“accretion-ripples” (Imbrie and Buchanan, 1965, p. 153), or “pararipples” (Purdy, 1961, p. 58). A few small-scale current ripples with wave lengths of 3 to 6 inches (8 to 15 cm) and amplitudes of half an inch to 2 inches (1 to 5 cm) have been seen. These ripples probably represent the ubiquitous small-scale ripples found superimposed on larger ripples of oolite bodies in the Bahamas (Ball, 1967, p. 559-560). Intraformational conglomerate commonly lies at the base of the oolitic limestone lithology and consists of rounded or angular detrital clasts that are as much as 3 inches (8 cm) long and that are composed of pellet-micritic or oolitic limestones. It can be recognized by the darker detrital fragments contrasting with the lighter colored oolitic limestone. The main stratigraphic attributes of the oolite body near Orleans are summarized in table 1.

CHEMICAL PROPERTIES: Total calcium and magnesium carbonate content of the oolitic limestone lithology has averaged more than 99 percent by weight in four groups of analyses made during the past 20 years (table 2). The samples were taken in the quarry within an area of about 1,000 square feet (93 sq m) near the place where the oolite body was thickest. This consistency in analyses indicates a horizontal homogeneity in composition within this area. Also, the analyses of two cores, samples LR63-1 to LR63-8 and LR63-58 to LR63-67 (table 2), which were taken from the top to bottom of the oolitic limestone lithology, indicate a vertical homogeneity in composition. The nearly complete lack of terrigenous material in the oolitic limestone lithology near Orleans should be emphasized. Such purity is not true for all oolitic limestones in the Illinois Basin, but a high calcium carbonate content is characteristic of many Ste. Genevieve oolitic limestones in the eastern and southern parts of the basin (Dever, 1969, p. 71; Lamar, 1957; McGregor, 1963; Patton, 1951, p. 263; Rooney, 1970; Stokley and McFarlan, 1952). Strontium content of five oolitic limestone samples from a core through the oolite body at Orleans averages 345 ppm (table 3). This value compares closely with an average strontium content of 375 ppm for 59 Paoli and Ste. Genevieve limestone samples from Indiana Geological Survey drill hole 150 (table 3). 30 GEOMETRY AND ORIGIN OF OOLITE BODIES OOLITE BODY NEAR ORLEANS, INDIANA 31 Table 3. Strontium content of Ste. Genevieve oolitic limestone near Orleans (A) and Ste. Genevieve and Paoli limestones from Indiana Geological Survey drill hole 150 (B) Sr content 1 Number of Thickness (ppm) Location Sample No. samples (ft) Per sample Range Average LR63-58 6.5 323 LR63-60 1.0 374 A LR63-62 2.5 384 LR63-64 3.4 370 LR63-67 2.9 274 Total 16.3 345 B 59 220-630 375

1A sampled from Indiana Geological Survey drill hole 104, Radcliff, Inc., quarry; B sampled from Indiana Geological Survey drill hole 150. SE1/4SE1/4 sec. 6, T. 1 N., R. 1 E., Orange County, Ind. Few analyses of strontium content of Mississippian oolitic limestones have been reported, but those reported compare closely with the values found for the oolite body at Orleans. Kahle (1965, p. 848) analyzed 25 Mississippian oolitic carbonate rock samples that had an average strontium value of 335 ppm. This value is remarkably similar to the average value found for the oolitic limestones at Orleans.

PHYSICAL PROPERTIES: Bulk specific gravity and absorption1 values were determined for samples taken at about l-foot (30 cm) intervals in the oolitic limestone lithology at four locations on the quarry face and in 12 cores. These tests were made to determine both the vertical and the horizontal variability of these physical properties in the oolite body. As absorption is directly related to the apparent porosity of a rock, it is important in interpreting electric log data of subsurface oolite bodies. Vertical profiles through the oolite body show that its middle part has higher absorption values and lower bulk specific gravity values than its upper and lower parts (fig. 18). The flank areas of the oolite body appear to have relative high values of bulk specific gravity and low values of absorption.

1 l Absorbtion is directly related to apparent porosity and is a measure of the inter- connected void space that opens to the surface of the test specimen. 32 GEOMETRY AND ORIGIN OF OOLITE BODIES

Y$yfgyr .s I-. .:**.... 6 \*_*_ _ **.* =y /o * . 0. . . . . ‘~.*.*.*.*.*.*. Y= ,.,, . * . . : *. * .* om *..-. ‘p ‘y.. . . * 0. * . . .*. ‘.*.. * ’ *.0 .*... \,:o 0.. / . ** ** . 1 ‘tx-l:, \*:4..* ,: - INTERPRETATION OF ENVIRONMENT 33 To compare the physical properties of its parts, the oolite body was separated into three parts:top and bottom (consisting of about the upper and lower 3 feet (0.9 m)), flanks, and middle. A parametric group comparison t-test (Steel and Torrie, 1960, p. 73-75) indicated that there was no significant difference in the mean value of absorption of the top and bottom and the flanks at the l-percent probability level. But the absorption values for flanks and top and bottom were found to be significantly lower than that of the middle part of the oolite body. A rind of less porous limestone surrounds a core of more porous limestone. Thus the three-dimensional shape of the interior part of the oolite body (high absorption zone) appears to approximate the true shape of the body. This relationship of the shape of the porosity zone to the shape of the oolite body itself is important in interpreting the shape of subsurface oolite bodies because electric log data indicate only the zones of porosity. Interpretation of Environment An important part of interpreting the environment of deposition is the setting of the oolite body in the basin, especially its orientation and relationship to paleocurrents. Fortunately, the Ste. Genevieve and Paoli Limestones lend themselves to basin and paleocurrent analysis because they contain abundant crossbedding. Also, oolitic limestones are found from base to top of the Ste. Genevieve and Paoli stratigraphic section.Thus deposition of the oolite body at Orleans does not imply unique conditions at this locality but rather implies a set of conditions that were common in the Illinois Basin throughout Ste. Genevieve and Paoli time. In order that the depositional environment at Orleans might be better interpreted, the size, shape, and angle of inclination of Ste. Genevieve and Paoli crossbedding and its orientation and variability were studied in the Illinois Basin.

PALEOCURRENTS

METHODS: Crossbedding was measured at sample intervals of about 6 miles (9.7 km) along the outcrop of the Paoli and Ste. Genevieve Limestones in Indiana, Kentucky, Illinois, and Missouri. Altogether 889 measurements were made at 147 outcrops (table 4). Crossbed- ding was best exposed in old road cuts, creekbeds, and old quarry faces where weathering enhanced its definition (Appendix B). The 34 GEOMETRY AND ORIGIN OF OOLITE BODI Table 4. Distribution of class intervals of crossbedding in Paoli and Ste. Ge- nevieve Limestones (and equivalent) at 147 outcrops in Illinois Basin [See windroses in figs . 23, 24, an d 25] Western Illinois Southern Illinois Eastern IlIinois Total Class IntervaI Basin Basin Basin

0- 40 26 53 91 170 41- 80 9 10 72 91 81-120 10 13 31 54 121-160 8 10 33 51 161-200 29 48 47 124 201-240 8 41 114 163 241-280 14 32 51 103 281-320 25 21 31 77 321-360 13 25 18 56

Total 142 253 494 889 vector mean, vector strength, normalized vector strength, and variance were calculated by the method described by Potter and Pettijohn (1963, p. 262-264).

RESULT S: Crossbedding is irregularly distributed, both laterally and vertically, in the Ste. Genevieve, but it is present in virtually all limestone types. It is best preserved in medium- to coarse-grained skeletal limestone but is also common in oolitic limestone. About 75 percent of the observed crossbeds have planar basal contacts and 25 percent have trough; however, distribution of a crossbed type around the basin is not preferential. At any particular outcrop one type of crossbedding generally predominates. Trough crossbedding appears to be more abundant in sedimentation units less than 0.4 foot (13 cm) thick. Figure 19 shows examples of typical crossbedded units. The modal class of bed thickness is the 4- to 8-inch (10- to 20cm) interval, and bed thickness approximates a log-normal distribution (fig. 20). The angle of inclination of the foresets also approximates a log-normal distribution with a modal class of 5° to 10° (fig. 21). To show crossbedding orientation around the basin more clearly, the outcrop was arbitrarily divided into eastern, southern, and western sections (fig. 22). The results of the directional measurement of crossbedding for each section are shown in figures 23, 24, and 25. INTERPRETATION OF ENVIRONMENT 35

0 10 Inches 1 1 0 25 Cm

Figure 19. Sketches of crossbedding in Ste. Genevieve Limestone. A, Road cut along State Road 37, 2 miles north of Orleans, lnd., NW1/4NW1/4 sec. 18, T. 3 N., R. 1 E., Lawrence County. B, Road cut along State Road 68, 3 miles east of Russellville, Ky., Logan County. C, Road cut along State Road 64-66, 1.4 miles east of Marengo, Ind., SW1/4NW1/4NE1/4 sec. 8, T. 2 S., R. 2 E., Crawford County. 36 GEOMETRY AND ORIGIN OF OOLITE BODIES

I 1 I 100

0/’

l 7/ /

80 0 8 16 24 32 40 48 56 Bed thickness (in.) / 70 aIz 60 ; & a 50 a) ._z ‘;; 40 7 E (3 30

- 20 30 40 50 70 90 Log Bed Thickness (cm)

Figure 20. Histogram and plot on logarithmic probability paper of observed thickness of crossbeds in Paoli and Ste. Genevieve Lime- stones (or equivalent) in the Illinois Basin (889 measurements). Note close approximation to a log-normal distribution. INTERPRETATION OF ENVIRONMENT 37 1 100

25 35 45 70 Q) Angle of lnclinotion of g Foresets (degrees) 60 E sL a” 50 0) .r ‘, 40 -Y E 3 30

5 10 15 20 25 30 35 40 Log Angle of Inclination of Foresets (degrees)

Figure 2 1. Histogram and plot on logarithmic probability paper of angle of inclination of foresets in Ste. Genevieve and Paoli Limestones (or equivalent) in the Illinois Basin (889 measurements). Note close approximation to a log-normal distribution. 38 GEOMETRY AND ORIGIN OF OOLITE BODIES 1

0 50 100 Miles 1 ” ‘I’ I 1 0 50 100 Km

Figure22. Index map showing locations of detailed maps of crossbedding in Ste. Genevieve and Paoli Limestones (or equivalent) in Illinois Basin.

The length of the arrow is proportional to the normalized vector strength at each sample location. The windrose diagram of 40º intervals for the eastern part of the basin (fig. 23) shows a primary mode to the southwest and a secondary mode to the northeast. The southern part of the basin has a more south-southwest by north- northeast orientation but still maintains a strong bimodal grouping (fig. 24). The western part of the basin exhibits more variable currents and a dominant mode to the south and secondary and tertiary modes to the north-northeast and northwest (fig. 25). The directional data have been summarized by combining the sample points into quadrates that are about equally spaced (fig. 26). INTERPRETATION OF ENVIRONMENT 39

EXPLANATION

o- 33% zz2L-0 r 0 niyn rtirm-tinn and vector stren-+k

Outcrop of Ste. Genevieve and Pooli Limestones

..‘.. j,.. Orleans

494 Obserwtions &

Figure 23. Map showing crossbedding directions in Ste. Genevieve and Paoli Limestones in Indiana and north-central Kentucky. 40 GEOMETRY AND ORIGIN OF OOLITE BODIES

EXPLANATION 0 30 Miles 1 ’ I’ ’ N r/Y 0 30 Km 0-33% 34-66% 67-100% Dip direction and vector strength

Outcrop of Ste. Genevieve and inFormation (or Renault Limestone)

3 Observations

Figure 24. Map showing crossbedding directions in Ste. Genevieve Limestone and Girkin Formation (or Renault Limestone) in southern Illinois and southern Kentucky. The vector mean and normalized vector length have been computed for each quadrate. The windrose for the entire basin shows a strong southwest-northeast bimodality with a grand mean of 248º.

INTERPRETATIO N: Abundant normal marine fossils and oolitic limestones throughout the stratigraphic section indicate deposition of Ste. Genevieve and Paoli limestones on a shallow marine shelf. It is highly unlikely that the ooliths formed in a hypersaline environment, because these rocks contain no evaporites or collapse structures associated with evaporite leaching. Thickness and angle of inclination of the crossbeds are evidence against an aeolian origin. Most limestone beds within the Ste. Genevieve are 4 to 8 inches (10 to 20 cm) thick, very thin when compared with most crossbeds of aeolian origin. Most crossbeds in the Ste. Genevieve incline at an angle of 10º to 15º) but most aeolian crossbeds are much steeper. Pleistocene aeolianites of Bermuda are as much as 75 feet (23 m) thick and have angles of inclination of 30º to 35º (MacKenzie, 1964, p. 55 and fig. 1). Typical aeolian crossbeds at White Sands National Monument, N. Mex., are medium to large scale and dip 30” to 34” (McKee, 1966, p. 59). Ball (1967, p. 580 and fig. 21) reported that Pleistocene INTERPRETATION OF ENVIRONMENT 41

142 Observations

EXPLANATION

Dip direction ond vector strength

Outcrop of Ste. Genevieve Lilnestone

Figure 25. Map showing crossbedding directions in Ste. Genevieve Lime- stone in southwestern Illinois and eastern Missouri. 42 GEOMETRY AND ORIGIN OF OOLITE BODIES

0 50 Miles I ‘I’ : ’ ’ 0 50Km

Figure 26. Map showing crossbedding directions in Ste. Genevieve and Paoli Limestones (or equivalent), summarized by sampling interval, in Illinois Basin. aeolian dunes in the Bahamas are as much as 150 feet (46 m) thick and that although they are composites, individual foresets incline to about 35º. The bimodal distribution of current directions also indicates that Ste. Genevieve limestones were deposited on a shallow marine shelf where the carbonate sands were washed back and forth on the shelf by water currents. The principal southwestern mode points down the paleoslope, and the secondary northeastern mode points upslope. The influence of ebb-and-flood tidal currents on shallow marine shelves has been reported in several studies that were reviewed by Klein (1967, p. 373-375). Highly variable orientation of crossbedding in sand bodies in the southern bight of the North Sea has been reported where flood currents do not follow the same path as ebb currents. But where the ebb-and-flood currents parallel each other, INTERPRETATION OF ENVIRONMENT

Figure 27. Current roses and vector means of crossbedding in sandstones of Chesterian Series and in Paoli and Ste. Genevieve Limestones in Illinois Basin and Salem Limestone in eastern part of Illinois Basin. Chesterian data from Potter and others, 1958, fig. 15; Salem data from Sedimentation Semi- nar, 1966, fig. 6.“n” is number of crossbedding measurements. crossbedding is more likely to oscillate through 180º (Houbolt, 1968, p. 258-261). Many sets of crossbeds in the North Sea area have 44 GEOMETRY AND ORIGIN OF OOLITE BODIE8

Ste. Genevieve

2 4 6 8 IO 12 14 Variance (in thousands)

Figure 28. Histograms of variance of crossbedding in sandstones of Pocono Formation (Mississip- pian), Dakota Group (Cretaceous) and Mans- field Formation (Pennsylvanian) and in Salem and Ste. Genevieve Limestones at outcrops where 15 or more measurements were made. Modified from Sedimentation Seminar, 1966, fig. 8. 180º bimodaldistribution (Reineck, 1963, figs. 18 and 19), as do modern carbonate sands in the Bahamas (Seibold, 1964, p. 239-244; Imbrie and Buchanan, 1965, p. 159; Ball, 1967, p. 569 and fig. 19). The 180º bimodal distribution of other ancient carbonate sand INTERPRETATION OF ENVIRONMENT 45 A B 20 - - - -

16 -

I mfJ 125 .

E 0 . 5 . ‘j a-, d , . .

4- . . . . . - - - 00 900 I 0 2 36C 00 7 F o 360” Azimuth

Figure 29. Diagram showing vertical profiles of crossbedding orientation in Ste. Genevieve Limestone. A, Road cut along State Road 64-66, 1% miles east of Marengo, Crawford County, Ind. B, Road cut along State Road 135, 2 miles northeast of Mauckport, Harrison County, Ind. C, Road cut near city park, Ste. Genevieve County, OM . deposits, which are believed to have formed in shallow marine conditions, has been attributed to tidal currents (Klein, 1965, p. 179- 191; Sedimentation Seminar, 1966, p. 112-113; Selley, 1967, p. 220- 222; Wilson, 1968, p. 108-l 12; Hamblin, 1969, p. 24; Knewtson and Hubert, 1969, p. 967; Adams, 1970, p. 94-97). Interpretation of a paleoslope to the southwest is compatible with current directions found in the Salem Limestone below the Ste. Genevieve and in the sandstones of the Chesterian Series above (fig. 27). In general, late Mississippian and post-Mississippian terrigenous sediments in the upper Mississippi Valley region have been transported southwestward (Potter and Pryor , 1961, fig. 15; Potter, 1963, p. 81-83; Sedimentation Seminar, 1966, fig. 7). The variability of current direction in the Ste. Genevieve is similar to that found in other marine shelf sands. The variance at individual 46 GEOMETRY AND ORIGIN OF OOLITE BODIES outcrops is mostly between 6,000 and 10,000 with a modal class of 6,000 to 8,000. The average variance is 6,161, which compares favora- bly with that of marine Salem limestones and contrasts with fluvially deposited sediments (fig. 28). Knewton and Hubert (1969, p. 960) found that the variance for crossbedded Ste. Genevieve carbonate sands in the western part of the Illinois Basin was 6,363, a variance very similar to that found in this study. The variance of most marine sands is 6,000 to 8,000, and the variances of fluvial-deltaic deposits are generally 4,000 to 6,000 (Potter and Pettijohn, 1963, p. 88-89). The variability of current directions at some individual outcrops is also bimodal and corresponds to that shown in the current directions for the regional areas (figs. 23, 24, and 25). This alternation of current direction is clearly shown in vertical profiles of crossbedding orientation at some outcrops (fig. 29).

BASIN SETTING The bimodally distributed current directions found in Ste. Genevieve and Paoli limestones suggest that the water depth was shallow during the deposition of the oolite body near Orleans. Close association of the body with normal marine skeletal limestones, desiccation polygons, and intraformational conglomerates and the complete absence of evaporites lend further support to a shallow marine shelf origin. The elongate oolite body at Orleans is oriented almost parallel to the ancient shoreline of the basin, as suggested by isopach mapping, and almost perpendicular to dominant bimodal current direction; however, the thicker part of the body is almost parallel to the current direction. Additional evidence for a shallow marine shelf origin of the oolite body near Orleans is its relationship with associated lithologies. The oolitic limestone lithology overlies a thin pellet-micritic limestone and a 10-foot-thick (3-m) skeletal (bryozoan) limestone, a sequence of lithologies almost identical with that found for the Miami Lime- stone (Pleistocene) in Florida. The facies relationships of the Miami Limestone are almost the mirror image of those of modern carbonate deposition near Cat Cay on the west edge of the Great Bahama Bank (Hoffmeister and others, 1967, p. 185-l87). Thus the depositional environment that produced the oolite body near Orleans appears to be similar to the modern shallow marine environment in the Bahamas. But there is no evidence to indicate that a major slope break, such as there is near Cat Cay, was present. INTERPRETATION OF ENVIRONMENT 47 Table 5. Comparison of attributes of oolite body near Orleans with modem marine sand belt in Bahamas. Marine sand belt (Ball. 1967. table 1) Oolite body near Orleans Relation to bottom topography On slope break. Slope break indeterminant. On gentle slope. Geometry Belt parallel to slope break. Parallel to inferred shoreline. Internal structure Crossbeds dipping perpendicular Crossbeds dipping bimodally, per- to long axis of belt with largest pendicular to long axis of body. sets at base and dipping predomi- Predominant mode is basinward nantly away from deeper or more toward more open water. open water. Composition Skeletal, pellet, or oolitic with Oolitic with laminae and thin beds whole marine megaskeletons and of skeletal and pellet. Sparry varying amounts of fibrous ara- calcite cement ranges from 1 to gonite cement. 35 percent, but most abundant alone bounding surface of body.

Orientation of the oolite body near Orleans normal to water currents is also evidence for a marine sand belt origin. This relationship is characteristic of marine sand belts (Purdy, 1961, p. 55; Ball, 1967, p. 558-563) and also of tidal bar. belts, although individual tidal bars are oriented parallel to water currents (Ball, 1967, p. 563- 572; Houbolt, 1968, p. 253). In summary, numerous characteristics of the oolite body near Orleans (table 5), when considered together, indicate a marine sand belt origin on a shallow marine shelf.

COMPARISON OF OOLITE BODY NEAR ORLEANS WITH OTHERS GEOMETRY: Ste. Genevieve oolitic limestones are present throughout the Illinois Basin. In the central part of the basin, in southwestern Indiana, southeastern Illinois, and northwestern Kentucky, these oolitic limestones, called informally McClosky sands or limes, are important reservoirs for oil. The McClosky sands are porosity zones that are recognized in the subsurface on electric logs by their negative spontaneous potential values. The zones are given alphabetical designations that depend partly on sequence from top to bottom and partly on position in the stratigraphic column (fig. 30). For example, the uppermost porous oolitic limestone in the Ste. Genevieve is designated “A zone”; 48 GEOMETRY AND ORIGIN OF OOLITE BODIES

7 a - CL a, - cn cn - cn cl3 -

Vertical Scale

Figure 30. Schematic representation of electric log and stratigraphic column showing position of McClosky porosity zones in Ste. Genevieve Lime- stone in Illinois Basin. “B zone” is generally applied to a porous zone directly below a shale below the A zone, but it is not always present. Other porosity zones below the B zone are lettered “C zone,” “D zone,” etc. Many of the McClosky porosity zones consist of very poorly cemented oolitic limestones that are encased by a rind of oolitic INTERPRETATIONOFENVIRONMENT 49 R.14W. R.13W.

A~~~~~, Feet

VERTICAL EXAGGERATION: 40X Figure 3 1. A, lsopach map of McClosky C porosity zone (oolitic limestone of Ste. Genevieve Lime- stone), Spencer Field, Posey County, Ind. B, Cross section of porosity zone. 50 GEOMETRY AND ORIGIN OF OOLITE BODIES limestone well cemented with sparry calcite. In some places, however, such as the Exchange area, Marion County, Ill., the porous oolitic limestones have been reported to be encased by dense fine-grained limestones and shales (Stevenson, 1969, p. 20). The relationship of cementation of the oolite body in the McClosky porosity zones appears to be similar to that found in the oolite body near Orleans. Thus it appears that some of the McClosky porosity zones, consisting of poorly cemented oolitic limestone, approximate the shape of the oolite body itself but are smaller in size. Figures 31, 32, and 33 show isopachs of McClosky porosity zones in three oilfields in the Illinois Basin. The Spencer Field in Posey County, Ind. (fig. 31), one of the largest McClosky producing fields in the Illinois Basin, is about 6 miles (9.7 km) long and 1.5 miles (2.4 km) wide. The more typical McClosky producing fields, such as the North Zion Field, Henderson County, Ky. (fig. 32), or the Martin Field, Vanderburgh County, Ind. (fig. 33), are smaller. These fields are about three quarters of a mile to 1 mile (1.2 to 1.6 km) wide and 2 to 4 miles (3.2 to 6.4 km) long. These dimensions are similar to those found by Connolly (1949, p. 22) for the McClosky A and B zones in the Passport Field, Clay County, Ill., which are from half a mile to 1 mile (0.8 to 1.6 km) wide and 1% to 2% miles (2.4 to 4 km) long. Most McClosky porosity zones in southeastern Illinois and southwestern Indiana have a north-south linear trend, as shown in the Spencer and Martin Fields, and a subparallel alignment. The North Zion Field in Kentucky, which has a northwest by southeast linear trend, is an exception and may indicate a more east-west orientation of McClosky porosity zones in western Kentucky. Thicker parts of most of the porosity zone are at angles of 30” to 90” to the main trend of the body (fig. 3 1). Truitt (195 1, fig. 4) mapped part of the McClosky C zone in secs. 1, 2, and 11 of the Spencer Field. His map also shows the thicker part of the oolite body to be aligned about N. 45” E. Similar orientation of McClosky porosity zones has been found in the Passport Field in Illinois (Connolly, 1949, fig. 10). These thicker parts of the porosity zone appear to be very similar to ridges that trend at angles to the long axis of the oolitic sand belts in the Bahamas (Baars, 1963, p. 114; Ball, 1967, p. 558). In cross section the McClosky porosity zones are interpreted as lenticular bodies with an almost flat basal surface and a concave INTERPRETATION OF ENVIRONMENT

. .

16 . 17

. EXPLANATION

DafuGpoint

-4- lsopach contour (Interval 4 feet) 0 I Mile t ’ ‘1’ ’ 0 1 Km

McClosky B porous zone

VERTICAL EXAGGERATION: 40X

Figure 32. A, Isopach map of McClosky B porosity zone (oolitic limestone of Ste. Genevieve Limestone), North Zion Field, Henderson County, Ky. B, Cross section of porosity zone. downward upper surface (figs. 3 lB, 32B, and 33B). Maximum thickness of individual porosity zones is only about 13 feet (4 m), and these zones appear as a thin sheet of sand at natural scale. 52 GEOMETRY AND ORIGIN OF OOLITE BODIES R. I I W.

EXPLANATION .

Datui point . 20 2 -4- . lsopoch contour (Interval 4 feet) 3 +- 3 IKm , PA’

29) 21 ; I III\‘ ! . . ! S. . /iYt 0 . . \\\h. [ /

McClosky C porous zone

VERTICAL EXAGGERATION: 40X

Figure 33. A, Isopach map of McClosky C porosity zone (oolitic limestone of Ste. Genevieve Limestone), Martin Field, Vanderburgh County, Ind. B, Cross section of porosity zone. I INTERPRETATION OF ENVIRONMENT 53 Comparison of the geometry of Ste. Genevieve oolite bodies with other ancient ones is difficult because so few detailed studies have been made. Only three studies that discussed the geometry of oolite bodies in sufficient detail to allow comparison could be found. The Ste. Genevieve oolite bodies are similar in some respects to the following: a Smackover (Jurassic) oolite body in northern Louisiana, a Rat- and Lias-Oolite body in the Northern Calcareous Alps of Upper Bavaria, and oolite bodies in the Sundance Formation (Juras- sic) of northwestern Wyoming. The Smackover oolite body is comparable in length and width to oolite bodies of the Ste. Genevieve, but it is much thicker (table 6). The greater thickness may be due to stacking, which would make it a multistoried sand body. The Smackover oolite body does contain alternating oolite and pellet limestones (Bishop, 1968, p. 117), which makes this interpretation reasonable, but stacking would be difficult to determine with assurance from only core data. The Rat- and Lias-Oolite body in the Northern Calcareous Alps is much longer and thicker than oolite bodies of the Ste. Genevieve, but the width is similar (table 6). Interbeds of calcareous mudstone in the Rat- and Lias-Oolite body (Fabricus, 1967, p. 162) suggest that it also may be a multistoried sand body. Oolitic sandstone bodies of the Sundance Formation (table 6) are generally smaller in plan dimensions than others described in the literature, but in thickness and nearly planar lower bounding surface (Stone and Vondra, 1967, p. 215) they are similar to Ste. Genevieve oolite bodies. As well as being comparable in lithology, lithologic relationships, and sedimentary structures, the Orleans oolite body is similar dimensionally to a modern oolitic marine sand belt in the Bahamas near Cat Cay (table 6). It would be difficult to distinguish between a tidal bar belt and a marine sand belt on the basis of only its size and shape. In general, however, oolite bodies of modern tidal bar belts are shorter and narrower than those of modern marine sand belts. In summary, the oolite body near Orleans is similar in size and shape to others in the Ste. Genevieve in the Illinois Basin and also comparable in some respects with other ancient oolite bodies. When compared dimensionally with modem oolitic deposits, the oolite body near Orleans appears to be most similar to those of marine sand belts in the Bahamas. GEOMETRY AND ORIGIN OF OOLITE BODIES INTERPRETATION OF ENVIRONMENT 55

TEXTURE: To compare textures, 55 samples of oolitic carbonates, representing all geologic periods except the Permian and Triassic, were studied (Appendix C). Only samples containing more than 50 percent coated grains were used, and no effort was made to determine their environment of deposition. Samples of Ste. Gene- vieve limestone used in the comparison study that did not contain more than 50 percent coated grains also were excluded. The grain size of 76 samples of oolitic limestone from the oolite body at Orleans ranged from 2.55ø to 0.57ø (0.17 mm to 0.67 mm), with a mean of 1.65ø (0.32 mm). Sorting values for these samples ranged from 0.53ø to 1.49ø, with an average of 0.85ø. These values are comparable with those obtained by Greenberg (1959, p. 60) in his petrographic study of Ste. Genevieve limestones in south-central Indiana. He found that the grain size of 25 samples of Ste. Genevieve oolitic limestone ranged from about 2.48ø to >l .0ø (0.18 mm to >.50 mm) and that sorting ranged from 0.50ø to 1.35ø (recast values from Trask sorting coefficients). Grain size and sorting of the oolitic limestones near Orleans are compared with the ancient oolitic limestones of the worldwide collection and with modern oolitic sand from the Bahamas in figure 34. Grain-size distribution of the Ste. Genevieve oolitic limestones and the modern oolitic sand from the Bahamas appears to be very similar, but these two groups differ slightly from the ancient oolitic limestones of the worldwide collection. This difference is not sur- prising because the oolitic limestones from the worldwide collection were probably deposited in different environments, but the Ste. Genevieve and Bahama oolites were probably deposited in similar environments. Oolitic carbonate sands also appear to be similar in grain-size distribution to mature shallow marine shelf quartz sands, such as the Ordovician sands of the St. Peter Sandstone and the Simpson Group. For example, straight-line plots indicate that the distribution of phi means closely approximates a normal probability distribution (fig. 35). The slightly steeper slope of the plot for the quartz sands indicates that they are less well sorted than are the oolitic carbonate sands. Thus the oolitic sand, which probably formed almost instantaneously in geologic time, is as well sorted as the multicycle quartz sand that reached its maturity over long geologic time. 56 GEOMETRY AND ORIGIN BODIES

g40 Ii=085 . 0 f z z A Q 20

0 0 .25 .75 1.25 1.75 2.252.75 0 .50 .70 .901.10 1.50 Groin size (@) Sorting (4) 60

g40 0 E E B d20

0 1.25 1.75 2.25 2.75 0 .50 .70 .90 I.10 I.50 Groin size (#I Sorting (41

40 5(= 0.63

% & 0 0 520 E U c FZO ; a f?

0 0 .25 .75 1.25 1.75 2.252.75 0 .50 .70 .90 1.10 i.50 Grain size ($1 Sorting ($1

Figure 34. Histograms of mean grain size and sorting of ancient and modem carbonate oolitic sands. A, Seventy-six samples of Ste. Genevieve oolitic limestone from oolite body near Orleans. B, Fifty-five oolitic carbonate samples from worldwide collection. C, Thirty-four samples of modern ooliths from South Cat Cay and Browns Cay, Bahamas (unpublished data courtesy of Edward G. Purdy, Esso Exploration, Inc.).

Average sorting of Ste. Genevieve oolitic limestones and oolitic limestones from the worldwide collection is similar. A parametric group comparison t-test (Steel and Torrie, 1960, p. 67-75) has indicated that there was less than one chance in a hundred that INTERPRETATION OF ENVIRONMENT

4.0

g 2.5

8 ;7j 2.0

c F -I0 1.5 c 8 = 1.0

t 0.5

I I I I I I -0.5 1 I I I I I I I I I I d 0.2 I 2 5 IO 20 30 40 50 60 70 80 90 95 99 99 99.8 Cumulative Percentage Frequency Figure 35. Data from figure 34 A, B, and C plotted on logarithmic probability paper to show close approach to straight-line fit. Compare fit of oolitic carbonate sands to that of St. Peter and Simpson quartz sands (Dapples, 1955, fig. 6). the two samples tested could have been obtained from different populations. Thus there seems to be a limiting value or best sorting of about 0.50 ø for ancient oolitic limestones; but comparing this value with the sorting in other ancient oolite bodies is difficult because of the scarcity of published detailed petrographic data. Fabricus (table 7) and Usdowski (table 7) obtained sorting values better than 0.50ø for ancient oolitic limestones, but they used measurements based on only oolitic grains. This method of measurement tends to improve sorting because it does not include measurement of the finer grained micritic material that is commonly present. Sorting values of modern oolitic sand tend to be somewhat better than those of ancient oolitic limestones (fig. 34 and table 7). A parametric group comparison t-test between sorting means of Ste. Gene- 58 GEOMETRY AND ORIGIN OF OOLITE BODIES Table 7. Comparison of grain size and sorting of some ancient and modern oolites Modern Size Location T Sorting range Range Mean Great Salt Lake 0.15 mm to 1.5 mm 0.31 mm (Eardley, 1938, p. 1364) (2.7ø to -0.6 ø) (1.7ø) lsla Mujeres, Mexico .18 mm to .35 mm .29 mm .50ø to l.0ø (straits) (Folk and others, (2.5ø to 1.5ø) (1.8ø) 1962, p. 94) Laguna Madre1 .25 mm to .5 mm .20ø to 1.30ø (Rusnak, 1960, p. 472) (2ø to lø) Bahamas2 .13 mm to 1.0 mm .35 mm .30ø to .80ø (Newell and others, 1960. (2.9ø to 0ø) (1.5ø) p. 487) Mediterranean coast, Tunisie and Egypt2 .14 mm to 1.3 mm .38 mm .30ø to .75ø (Lucas. 1955, p. 22) (2.8 ø to -.4ø ) (1.4ø) Mediterranean coast, Egypt2 .14 mm to .90 mm .40 mm .50ø to .60ø (Hilmy, 1951, p. 112-113) (2.8 ø to .15 ø) (1.3ø)

Size 1 Sorting Location Range Mean Range Mean Liassic Oolite2, 3 0.35 mm to 0.7 mm0.47 mn .25 ø to .72 ø Y$ (Fabricus, 1967, p. 158) (1.5 ø to .5ø ) (l.lø) Rat- and Lias-Oolite2, 3 0.1 mm to 0.5 mm 0.31 mn .30 ø to .95 ø .65ø (Fabricus, 1967, p. 158) (3ø to lø) (1.7 ø ) Great Oolite Series .25 mm to 1.5 mm (Klein, 1965 , p. 179-180) (2ø to -.5ø) Unteren Buntsandstein oolites2, 3 0.20 mm to 3.5 mm .25 ø to 1.0 5ø ) (Usdowski , 1962, p. 151-154) (2.32ø to -1.8ø) Smackover Limestone .125 mm to 1 mm (Bishop, 1968, p. 103) (3ø to 0ø) Ste. Genevieve Limestone .18 mm to .7 mm .32 mm (this study) (2.55ø to 0.50ø) (1.65ø) 55ø to l.5ø .85ø Worldwide oolitic limestones .15 mm to 1.4 mm .42 mm 49ø to l.5ø . (this study) (2.7ø to -0.540 (1.25ø) Ste. Genevieve Limestone2 .18 mm to > .50 mm 50ø to 1.3ø) (Greenberg, 1959, p. 60) (2.48ø to > 1.0ø)

lInman sorting coefficient recast as standard deviation according to Friedman (1962b, p. 746). 2Trask sorting coefficient recast as standard deviation according to Friedman (1962b , p. 749). 3Statistics computed for only the oolitic grains. INTERPRETATION OF ENVIRONMENT 59 vieve oolitic limestones and modern oolitic sand from the Bahamas and between sorting means of Ste. Genevieve oolitic limestones and modern oolitic sand from the Mediterranean coast as described by Lucas (1955, p. 22) failed to indicate that either of each pair of populations had similar means. This result suggests that sorting values of ancient oolitic limestones and modern oolitic sands are somewhat similar but that in general modern oolitic sands tend to be better sorted than ancient oolitic limestones. One possible explanation why modern oolitic sands are better sorted than ancient oolitic limestones is that fine-grained carbonate may be lost during underwater sampling of modern deposits. Another explanation may be that fine-grained carbonate settles down through pore openings and is incorporated into the undisturbed part of the oolite body during growth. The addition of fine-grained carbonate would tend to worsen the sorting. Plots of mean grain size versus standard deviation were prepared for the Ste. Genevieve oolitic limestones, the worldwide collection of oolitic carbonates, and Bahamian oolitic sand (fig. 36) to ascertain if any environmental significance could be detected. Beach and river environment lines (Friedman, 1967, fig. 14; Moiola and Weiser, 1968, fig. 6) have been added to the plots for comparison. Data for oolitic sands are rather random, which indicates that the environment that produced the oolitic sands is unlike either the beach or river environments. A line parallel to the Moiola and Weiser line, but favoring better sorting, would include all the data points for the Ste. Gene- vieve oolitic limestones, but the Friedman line appears to give the best fit for the worldwide collection of oolitic carbonates. Plots of mean grain size versus standard deviation are also effective in differentiating between river and coastal dune sands (Moiola and Weiser, 1968, p. 5 1 and fig. SC). The environment that produced the oolitic sands also does not show any similarity to either the river or coastal dune environments. These combinations of textural parameters apparently fail to show any similarity between the environment of deposition of oolitic sand and the environments of deposition of river, coastal dune, or beach quartzose sands. Plots of oolitic grain size versus skewness were also made, but no significant trend was noted. Skewness alone, however, has been used to distinguish between autochthonous and allochthonous oolites. Lacey and Carozzi (1967, p. 303) concluded from a petro- 60 GEOMETRY AND ORIGIN OF OOLITE BODIES

3- .: ,’ . . ‘. d . Pr’P .* PlcL l s,_ pl-7 . . ‘73 E \8’**” l . ‘5 I.* l . . 2. ,‘_a:. . . l * l .G l . .* ‘& + . l 7.8. . e t A (3 I- \,’ s:

0 \ I I I I I I , 0.4 0.6 0.8 1.0 1.2 1.4 1.6 Sorting ($1 3 1

,’ l : ,Friadmon (1967)

. . .

. I 1 I I I 0.4 0.6 0.8 1.0 I.2 1.4 1.6 Sorting (4) 3?

0.4 0.6 0.8 1.0 1.2 I.4 I.6 Sorting (41 Figure 36. Plot of mean grain size versus sorting of ancient and modern carbonate oolitic sands. A, Seventy-six samples of Ste. Genevieve oolitic limestone from oolite body near Orleans. B, Fifty-five oolitic carbonate samples from worldwide collection. C, Thirty-four samples of modern ooliths from South Cat Cay and Browns Cay, Bahamas (unpublished data courtesy of Edward G. Purdy, Esso Exploration, Inc. INTERPRETATION OF ENVIRONMENT 61 graphic study of Ste. Genevieve oolitic limestones in southern Illinois that autochthonous oolites had a mean skewness value of +0.22 but that three different types of allochthonous oolites had mean skewness values of +0.07, -0.17, and -0.13. The mean skewness value for the oolite body at Orleans is +0.24, remarkably similar to that found for autochthonous oolites by Lacey and Carozzi. Thus the suggestion that the oolite body at Orleans consists of oolitic sands formed mostly at their site of deposition is compatible with the interpretation that the body was deposited as a marine sand belt.

MAIN EVENTS IN DEPOSITION During Ste. Genevieve time the eastern shelf of the Illinois Basin sloped gently westward, probably an average of less than 0.5 foot (15 cm) per mile, in the Orleans area. On this broad shelf a community of organisms, probably consisting mainly of bryozoans, contributed sediments, which now are represented by about 10 feet (3 m) of skeletal limestones. Organic growth was more vigorous on some parts of the shelf than on others, so that a few areas developed sufficient topographic relief to cause shoaling. Water currents in the shoal areas disturbed bottom sediments of skeletal fragments and pellets, which, as they became agitated, developed oolitic coatings from the CaCO3-saturated waters. Production of ooliths began. Development of the oolite body was dynamic in that as the number of ooliths increased, the water shallowed, the currents became stronger, and more ooliths were formed. An elongate lenticular body of oolitic sand, about 2 miles (3.2 km) wide and greater than 4 miles (6.4 km) long, developed with a north- south orientation, almost perpendicular to the paleoslope of the basin. Water currents moving across the sand body in response to tides and wind formed sand waves that left behind a record of crossbedding with a bimodal direction of dip to the northeast and southwest. Almost no terrigenous material reached the site of oolith formation. The oolith nuclei consist almost entirely of carbonate grains of pellets or skeletal fragments. The oolith nuclei came from near the place where the oolite body developed, and after coats of calcium carbonate were precipitated from tho CaCO3-saturated waters, the ooliths were deposited not far away. The finer grain size in the basal part of the oolite body reflects 62 GEOMETRY AND ORIGIN OF OOLITE BODIES the admixing of pellets and ooliths during the early genesis of the ooliths. As shoaling increased, the currents became more capable of agitating the grains, so that the grains became larger and attained an average size of about 1.474 (0.36 mm) in the upper part of the oolite body. The general uniformity of the currents throughout deposition of the oolite body is expressed in the uniformity of grain sorting, which averages about 0.90ø. As stronger currents washed oolitic grains away from the normal confines of the oolite body toward the quieter water of the shelf lagoon, the body grew onto the shelf over the pellet muds and the biotic community. The shelf over which the oolite body developed was rather flat, as its flat basal surface shows. As the body became thicker, its weight caused deformation of the incompetent pellet muds below and diapiric intrusion into the oolite body. Along with growth of the oolite body, lagoonal shelf sediments built up, and as the water became progressively shallower, a rather extensive tidal flat developed shoreward. The impure limestone lithology of the Ste. Genevieve must have been deposited as the tidal flat encroached and moved seaward over the oolitic limestone lithology. Numerous thin crossbedded limestones of various types indicate that shallow waters covered parts of the area; but terrigenous materials consisting of clay, silt, and sand were also brought in from a land source not far to the east. From time to time subaerial exposure of the flat dessicated the sediments and left behind micritic and pelletal limestone breccias and dessication polygons. Algal mats also thrived in parts of the shallow marine tidal flat, as their structures found in the finer grained limestones show, and a marine fauna actively burrowed the carbonate sediments. The concept of tidal-flat regression has been used to explain the origin of part of the Osmington Oolite Series (Jurassic) in England (Wilson, 1968, p. 10- 112). Klein (1965, p. 189-191) also recognized a tidal-flat regression cycle for part of the Great Oolite Series (Juras- sic) in England and found evidence for associated tidal channels. Tidal channels have not been observed in the Ste. Genevieve impure limestone lithology near Orleans, but channels of primary origin reported in the Ste. Genevieve near Cave-in-Rock, Ill. (Park and Amstutz, 1968, p. 68-76), may represent tidal channels. Penecontemporaneous with or after deposition of the oolitic limestone lithology, calcium carbonate was precipitated in the interstices, OOLITE BODY PREDICTION 63 mainly along the bounding surface of the body. Ball (1967, p. 563, fig. 13) reported that an aragonitic cement was commonly found growing radially from the grain boundaries to the interstices on the surface of the oolitic sand belts in the Bahamas. Aragonitic cement is found mainly in areas where grains have remained immobile for some time, so that burrowing organisms have had time to alter the depositional packing and leave behind a mucoidal slime on burrow boundaries that promotes the precipitation of aragonite. Burrow structures are found in the pellet-micritic limestones both above and below the oolitic limestone lithology at Orleans, so that it seems reasonable that the burrowing fauna would have worked at least some distance into the oolite body. But the carbonate cement is entirely sparry calcite in a mosaic pattern (.05 to .5 mm), which is typical of that derived from the dissolution of aragonite and rede- posited by fresh water (Friedman, 1968, p. 17-19). Thus it appears that the oolitic limestone lithology was subjected to fresh waters through subaerial exposure shortly after deposition or later by circu- lating waters in the subsurface. Deposition of sparry calcite cement was probably postdepositional, but its time of emplacement is not certain. Apparently, the greater concentration of sparry calcite along the margins of the oolite body may partially reflect the burrowing activity that concentrated the initial precipitation of aragonite cement. This interpretation of the depositional sequence of the oolite body near Orleans proposes a cycle of deposition beginning with the development of an organic community on a shallow marine platform and terminating with the regression of a tidal flat over the oolite body. These conditions were not unique at Orleans. Oolite bodies were being formed at many places in the basin where conditions were similar to those at Orleans. Continuous or periodic basin subsidence resulted in a cyclic transgression and regression of sea level that with time caused oolite deposition to shift to different parts of the basin. Thus the episodic oolitic deposition near Orleans was repeated in different parts of the Illinois Basin throughout Paoli and Ste. Gene- vieve time, which is shown by the multiplicity of oolite bodies found in the stratigraphic section. Oolite Body Prediction What can be said about predicting the location of oolite bodies in the 64 GEOMETRY AND ORIGIN OF OOLITE BODIES Illinois Basin? And once an oolite body is located, what can be said about its orientation in the basin? Certainly answers to these ques- tions are important economically if one is looking for a source of high-calcium limestone or for a petroleum reservoir. Knowing the geometry of the oolite body is also important if one wants to exploit the deposit most economically. Only part of the ubiquitous oolitic limestones of the Ste. Gene- vieve and Paoli in the Illinois Basin formed as marine sand belts. Probably a large part of the oolitic sands originated as thin discontinuous sand blankets, perhaps winnowed and transported some distance from their places of origin. Such movement of oolitic sands has been postulated for some Ste. Genevieve oolitic limestones in southern Illinoi (Laceys and Carozzi, 1967, p 295-304). . Similar sand blankets no doubt exist throughout the Illinois Basin. Other oolitic sands may have been deposited as tidal bars or perhaps as aeolian dunes Ooliti. c sand bodies with such diverse origin can be observed on the shallow Bahamian platform (Ball, 1967, p 556) , whose. area of about 100,000 square miles (259,000 sq km) is some three times larger than the area occupied by the Chesterian sediments in the Illinois Basin. Thus it seems reasonable to expect that the Ste. Gene- vieve and Paoli oolitic sands in the Illinois Basin were deposited under various depositional conditions. Bottom topography and its effect on water currents have been emphasized by Ball (1967, p 585-59. 0) as controlling factors in the distribution, orientation, and shape of sand bodies. There is no indication that topographic relief was large in the Illinois Basin during deposition of Paoli and Ste. Genevieve limestones. Probably only small relief existed on a shallow shelf that may have sloped basinward at less than 0.5 foot (15 cm) per mile. This small amount of relief was sufficient, however, to control currents that formed the sand bodies. For Orleans a depositional model has been postuIated whereby more active biohermal growth parallel to the ancient shoreline caused shoaling, which in turn initiated the formation of ooliths. Once the oolite body began to grow, it created shallower water, which in turn favored greater oolite formation. Such a model does not require a sharp slope break to form currents for localizing the deposition of oolitic sand, but rather it depends on a bioherm to form a constriction that initiates shoaling. It is recognized, of course, that elsewhere in the basin slight tectonic warping might have also OOLITE BODY PREDICTION 65 initiated shoaling. Thus oolitic sand deposition was not limited to one geographic area in the Illinois Basin but continually shifted throughout Paoli and Ste. Genevieve time. Predicting the location of ancient marine shelf sand bodies is difficult (Potter, 1967, p. 359), and prospecting for individual Paoli and Ste. Genevieve oolitic marine sand belts is no exception. There appears to be no good way to prospect for the causal factors of oolite formation, which at Orleans would require looking for skeletal limestones with topographic highs of a few feet. Not only is mapping carbonates difficult because of irregularity and lack of key beds, but more importantly the topographic highs that controlled water currents that initiated the process by which oolites are formed would be found beneath the oolite body itself. Looking for a topographic high after the fact is not an efficient way to explore for mineral deposits. At present it appears that the best way to explore for oolite bodies in the subsurface is to look for structural highs. This has been done because most Ste. Genevieve oil production comes from pools on anticlinal structures. Perhaps by drilling on structures, oolitic sand bodies will be found fortuitously. Equally difficult is determining the type of oolite body encoun- tered in the subsurface by the drill bit. A typical core through the Paoli and Ste. Genevieve Limestones along the eastern part of the Illinois Basin may encounter 10 to 20 oolite beds. Most of these beds will range from 0.5 to 1 foot (15 to 30 cm) in thickness. Because of their petrographic homogeneity, it is difficult to determine whether a single thin oolite bed represents a thin discontinuous sand blanket or the flank of a thick marine sand belt. The oolite bed would not be expected to thicken if it were a sand blanket, but if it were a sand belt, the thicker part of the body may lie only a short distance away. It seems doubtful that petrographic examination will provide the clues of origin. Also, sedimentary directional structures are not readily available in the subsurface. Here again it appears that drilling and isopach mapping are the best means at present of distinguishing the different types of subsurface oolite bodies. Once an oolite body has been located, how will it lie? The orientation of other similar sand bodies should be considered, because similar conditions may be expected to exist during successive sitional cycles in a basin where paleoslope was stable for appreciable periods of time (Potter, 1967, p. 358). A north-south orientation of 66 GEOMETRY AND ORIGIN OF OOLITE BODIES many Paoli and Ste. Genevieve oolite bodies in parts of the Illinois Basin is characteristic. Where isopach and crossbedding mapping have been made in Indiana, the elongate sand bodies appear to lie almost perpendicular to the paleoslope of the basin. Thus when one is looking for oolite bodies near the outcrop, isopach and crossbedding mapping may be the best means of predicting orientation of subsurface oolitic marine sand belts. Summary GEOLOGIC ASPECTS 1. Oolitic limestones of the Ste. Genevieve and Paoli Limestones (and stratigraphically equivalent formations) are found throughout the Illinois Basin. These oolitic limestones constitute 22 percent of the two formations in seven cores equally spaced along the length of outcrop in southern Indiana, which lies on the eastern margin of the Illinois Basin. In vertical profile these oolitic limestones are rather evenly distributed, but most are in the upper half of the stratigraphic section. 2. Analysis of crossbedding in the Illinois Basin indicates that movement of Ste. Genevieve and Paoli carbonate sands was variable; the principal mode of current direction was to the southwest and the secondary mode was to the northeast. Most beds are 4 to 8 inches (10 to 20 cm) thick, and the angle of inclination of crossbeds is 10º to 15º. . The average variance of crossbedding directions at individual outcrops is 6 161, which is similar to that reported for other shallow-shelf marine sands. 3. Principal effort was directed at an elongate lenticular oolite body in the Ste. Genevieve Limestone near Orleans, Orange County, Ind., which is about 2 miles (3.2 km) wide and more than 4 miles (6.4 km) long. Its lower boundary surface is almost flat, and its upper surface arches upward to a maximum thickness of about 25 feet (7.6 m). The oolite body is oriented almost perpendicular to the paleoslope of the east side of the basin, as determined by isopach mapping and measurement of crossbedding. 4. Four principal carbonate lithologies are associated with the oolite body near Orleans: a skeletal (bryozoan) limestone lithology, a pellet-mud carbonate lithology, an oolitic limestone lithology, and an impure limestone lithology. The relationship of these lithologies, SUMMARY 67 along with the three-dimensional shape of the oolite body and sedimentary structures associated with the body, suggests that it formed as a marine sand belt, much like those forming today in the Bahamas. 5. The size and shape of some Ste. Genevieve oolite bodies in the subsurface of the Illinois Basin, as determined by isopach mapping of porosity zones, suggest that they too may have formed as marine sand belts. Where measured, these oolite porosity zones range from 2 to 6 miles (3.2 to 9.7 km) in length and 3/4 to 1½ miles (1.2 to 2.4 km) in width and are as much as 13 feet (4 m) thick. 6. Although few comparisons are possible, the geometry of Ste. Genevieve oolite bodies is similar in some respects to oolite bodies in the Smackover Limestone in northern Louisiana, the Rat- and Lias-Oolite in the Northern Calcareous Alps, and the Sundance Formation in northwestern Wyoming. 7. The oolitic limestone lithology near Orleans is medium grained, and its average grain size is 1.47ø (0.36 mm). Although the average sorting value is 0.904, the center part of the oolite body has a limiting value of 0.50ø. Grain-size distributions are generally negatively skewed along the base of the oolite body but range from about 0 to +0.50 in the middle and upper part of the body. 8. The grain-size distribution of Ste. Genevieve oolitic limestones is comparable with that of other ancient and modern marine oolites. Few marine ooliths exceed 1 mm in diameter and most average about 0.35 mm. Grain sorting of Ste. Genevieve oolitic limestones is similar to that found in other ancient oolitic limestones from all parts of the geologic column. But sorting is poorer in ancient than in modern oolites. The best grain sorting for ancient oolitic limestones is about 0.50ø. 9. Plots of grain size and standard deviation and of grain size and skewness fail to show any similarity between the environment of deposition of oolitic sands and the environments of deposition of river, coastal dune, or beach quartzose sands. Carbonate oolitic sand, which has formed almost instantaneously in geologic time, appears to be better sorted than mature multicycle quartz sands, which have formed over a long geologic time. 10. Predicting the location of oolitic marine sand belts in a basin is difficult; however, isopach mapping and crossbedding analysis may help in determining the orientation of these bodies near the outcrop. 68 GEOMETRY AND ORIGIN OF OOLIT’E BODIES

CHEMICAL AND PHYSICAL ASPECTS 1. The total carbonate (Ca + Mg) content of the oolitic limestone lithology near Orleans has consistently averaged more than 99 percent by weight in four groups of tests. Magnesium carbonate generally averages less than 1 percent. 2. The average strontium content of the oolitic limestone lithology near Orleans is 345 parts per million. This is similar to the average value obtained for other Ste. Genevieve and Paoli limestones in Indiana, which is 375 parts per million. Strontium content of Ste. Genevieve oolitic limestone is comparable with that reported for other Mississippian carbonate oolites, which is about 335 parts per million. 3. The average bulk specific gravity for the oolitic limestone lithology near Orleans is 2.54, and the average apparent porosity (absorption) is 2.41 percent. The apparent porosity is significantly lower along the bounding surface of the oolite body because of cementation by sparry calcite. A relatively high apparent porosity in the middle part of the oolite body appears to be similar to the McClosky porosity zones in subsurface oolite bodies of the Illinois Basin. Literature Cited Adams, R. W. 1970 -Loyalhanna Limestone-cross-bedding and provenance, in Studies of Appalachian geology: central and southern: New York, John Wiley & Sons, p. 83-100. American Society for Testing and Materials 1968-Concrete and mineral aggregates, pt. 10 of Book of ASTM standards: 631 p. Baars, D. L. 1963 -Petrology of carbonate rocks, in Shelf carbonates of the Paradox Basin, a symposium: Four Corners Geol. Soc., 4th field conf., p. 101-129. Ball, M. M. 1967 -Carbonate sand bodies of Florida and the Bahamas: Jour. Sed. Petrology, v. 37, p. 556-591. Balthaser, L. H. 1969 -Petrology and paleoecology of middle Chester (Mississippian) rocks of the southwestern Indiana outcrop [Ph. D. thesis] :Blooming- ton, Indiana Univ., 257 p. LITERATURE CITED 69 Bishop, W. F. 1968-Petrology of upper Smackover Limestone in North Haynesville Field, Claibome Parish, Louisiana: Am. Assoc. Petroleum Geologists Bull., v. 52, p. 92-128. Carozzi, A. V. 1961 -Distorted oolites and pseudoolites: Jour. Sed. Petrology, v. 3 1, p. 262-274. 1962-Cerebroid oolites: Illinois Acad. Sci. Trans., v. 55, p. 239-249. Connolly, F. T. 1949 -The geology of the Passport oil pool Clay County, Illinois [M.S. thesis] : Cincinnati, Ohio, Cincinnati Univ., 33 p. Dapples, E. C. 1955 -General lithofacies relationship of St. Peter Sandstone and Simpson Group: Am. Assoc. Petroleum Geologists Bull., v. 39, p. 444-467. Dever, G. R., Jr. 1969 -High-calcium and low-magnesium limestone resources in the region of the lower Cumberland, Tennessee, and Ohio Valleys, western Kentucky: Kentucky Geol. Survey Bull. 5, ser. 10,192 p. Eardley, A. J. 1938 -Sediments of Great Salt Lake, Utah: Am. Assoc. Petroleum Geolo- gists Bull., v. 22, p. 1305-1411. Fabricus, Frank 1967 -Die Rat- und Lias-Oolithe der nordwestlichen Kalkalpen: Geol. Rundschau, v. 56, p. 140-170. Fisk, H. N. 1960 -Bar-finger sands of Mississippi delta, in Geometry of sandstone bodies: Tulsa, Okla., Am. Assoc. Petroleum Geologists, p. 29-52. Folk, R. L. 1965-Petrology of sedimentary rocks: Austin, Tex., Hemphill’s, 159 p. Folk, R. L., and others 1962 -Carbonate sediments of Isla Mujeres, Quintana Roo, Mexico and vicinity, in Guidebook, Field trip to Peninsula of Yucatan: New Orleans Geol. Soc., p. 85-100. Friedman, G. M. 1962a -Comparison of moment measures for sieving and thin-section data in sedimentary petrological studies: Jour. Sed. Petrology, v. 32, p. 15-25. 1962b -On sorting, sorting coefficients, and the log-normality of the grain size distribution of sandstones: Jour. Geology, v. 70, p. 737-756. 1967 -Dynamic processes and statistical parameters compared for size frequency distribution of beach and river sands: Jour. Sed. Petrology, v. 37, p. 327-354. 70 GEOMETRY AND ORIGlN OF OOLITE BODIES Friedman, G. M. 1968 -The fabric of carbonate cement and matrix and its dependence on the salinity of water, in Recent developments in carbonate sedimentology in Central Europe: New York, Springer-Verlag, p. l1- 20. Graf, D. L., and Lamar, J. E. 1950 - Petrology of Fredonia oolite in southern Illinois: Am. Assoc. Petro- leum Geologists Bull., v. 34, p. 2318-2336. Greenberg, S. S. 1959 -Petrography of the Ste. Genevieve Limestone in Indiana [Ph. D. thesis] : Bloomington, Indiana Univ., 77 p. Hamblin, W. K. 1969 -Marine paleocurrent directions in limestones of the Kansas City Group (Upper Pennsylvanian) in eastern Kansas: Kansas Geol. Survey Bull. 194, pt. 2, 25 p. Hilmy, M. E. 1951 -Beach sands on the Mediterranean coast of Egypt: Jour. Sed. Petrology, v. 21, p. 109-120. Hoffmeister, J. E., and others 1967 - Miami Limestone of Florida and its Recent Bahamian counterpart: Geol. Soc. America Bull., v. 78, p. 175-190. Houbolt, J. J. H. C. 1968 -Recent sediments in the southern bight of the North Sea: Geologie en Mijnbouw, v. 47, p. 245-273. Imbrie, John, and Buchanan, Hugh 1965 -Sedimentary structures in modern carbonate sands of the Bahamas, in Primary sedimentary structures and their hydrodynamic interpretation: Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 12, p. 149-172. Kahle, C. F. 1965 -Strontium in oolitic limestones: Jour. Sed. Petrology, v. 35, p. 846- 856. Kissling, D. L. 1967 -Environmental history of lower Chesterian rocks in southwestern Indiana [Ph. D. thesis] : Bloomington, Indiana Univ., 367 p. Klein, G. deV. 1965 -Dynamic significance of primary structures in the Middle Jurassic Great Oolite Series, southern England, in Primary sedimentary structures and their hydrodynamic interpretation: Soc. Econ. Paleontologists and Mineralogists Spec. Pub. 12, p. 173-l91. 1967-Paleocurrent analysis in relation to modern marine sediment dispersal patterns: Am. Assoc. Petroleum Geologists Bull., v. 51, p. 366 - 382. LITERATURE CITED 71 Knewtson, S. L., and Hubert, J. F. 1969 -Dispersal patterns and diagenesis of oolitic calcarenites in the Ste. Genevieve Limestone (Mississippian), Missouri: Jour. Sed. Petrolo- gy, v. 39, p. 954-968. Krumbein, W. C., and Libby, W. G. 1957 -Application of moments to vertical variability maps of stratigraphic units: Am. Assoc. Petroleum Geologists Bull., v. 41, p. 197-212. Krumbein, W. C., and Sloss, L. L. 1956-Stratigraphy and sedimentation: San Francisco, Calif., W. H. Freeman and Co., 497 p. Lacey, J. E., and Carozzi, A. V. 1967 -Critères de distinction entre oolithes autochtones et allochtones application au calcaire de Sainte-Geneviève (Viséen) de 1’Illinois (U.S.A.): Bull. Centre Recherches Pau-SNPA, v. 1, no. 2, p. 279- 313. Lamar, J. E. 1957-Chemical analyses of Illinois limestones and dolomites: Illinois Geol. Survey Rept. Inv. 200, 33 p. Leith, C. J. 1949 -Oolitic facies of Middle Mississippian Ste. Genevieve Formation in Indiana: Oil and Gas Jour., v. 47, no. 46, p. 152. Lucas, Gabriel 1955 -Oolithes marines actuelles et calcares oolithiques recents sur la rivage Africain de la Mediterranee orientale (Egypte et sud Tunisien): Sta. Oceanographique de Salammbo (Tunisie) Bull. 52, Septembre, p. 1938. MacKenzie, F. T. 1964 -Bermuda Pleistocene eolianites and paleowinds: Sedimentology, v. 3, p. 52-64. McGregor, D. J. 1963 -High-calcium limestone and dolomite in Indiana: Indiana Geol. Sur- vey Bull. 27, 76 p. McKee, E. D. 1966-Structures of dunes at White Sands National Monument, New Mexico (and a comparison with structures of dunes from other selected areas): Sedimentology, v. 7, 69 p. McKee, E. D., and Goldberg, Moshe 1969 -Experiments on formation of contorted structures in mud: Geol. Soc. America Bull., v. 80, p. 23l-244. Malott, C. A. 1952-Stratigraphy of the Ste. 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Purdy, E. G. 1961 - Bahamian oolite shoals, in Geometry of sandstone bodies: Am. Assoc. Petroleum Geologists Symposium, p. 53-62. 1964 - Sediments as substrates, in Approaches to paleoecology: New York, John Wiley & Sons, p. 238-271. LITERATURE CITED 73 Radwanski, Andrzej 1965 - Procesy Wciskowe W osadach klastycznych I oolitowych (Pitting processes in clastic and oolitic sediments): Geol. Soc. Poland Ann., v. 35, p. 179-210. Reineck, H. E. 1963 -Sedimentgefüge im Bereich der südlichen Nordsee: Senckenberg. naturf. Gesell. Abh., v. 505, p. l-90. Rich, J. L. 1948 -Submarine sedimentary features on Bahama Banks and their bearing on distribution patterns of lenticular oil sands: Am. Assoc. Petro- leum Geologists Bull., v. 32, p. 767-779. Rittenhouse, Gordon 1949 - Petrology and paleogeography of Greenbrier Formation: Am. Assoc. Petroleum Geologists Bull., v. 33, p. 1704-l 730. Rooney, L. F. 1970 - High-calcium limestone and high-magnesium dolomite resources of Indiana: Indiana Geol. Survey Bull. 42-B, 20 p. Rusnak, G. A. 1960 -Some observations of Recent oolites: Jour. Sed. Petrology, v. 30, p. 471-480. Sedimentation Seminar 1966 -Cross-bedding in the Salem Limestone of central Indiana: Sedimen- tology, v. 6, p. 95-114. Seibold, Eugen 1964 - Beobachtungen zur Schictung in Sedimenten am Westrand der Great Bahama Bank: Neues Jahrb. Geologie u. Paläontologie Abh., v. 120, p. 233-252. Selley, R. C. 1967 - Paleocurrents and sediment transport in nearshore sediments of the Sirte Basin, Libya: Jour. Geology, v. 75, p. 215-223. Shrode, R. S. 1949 -Physical characteristics of the oolite grains of the Ste. Genevieve Formation: Illinois Acad. Sci. Trans., v. 42, p. 116-l 19. Steel, R. G. D., and Torrie, J. H. 1960- Principles and procedures of statistics: New York, McGraw-Hill, Inc., 481 p. Stevenson, D. L. 1969 -Oil production from the Ste. Genevieve Limestone in the Exchange Area, Marion County, Illinois: Illinois Geol. Survey Circ. 436, 23 p. Stokely, J. A., and McFarlan, A. C. 1952 -Industrial limestones of Kentucky No. 2: Kentucky Geol. Survey Rept. Inv. 4,94 p. 74 GEOMETRY AND ORIGIN OF OOLITE BODIES Stone, Randolph, and Vondra, C. F. 1967 -Geometry and paleocurrent analysis of certain sandstone bodies in the Sundance Formation of northwestern Wyoming [abs.] : Geol. Soc. America Ann. Meeting Program, New Orleans, p. 215-216. Swarm, D. H. 1963 -Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois Geol. Survey Rept. Inv.216, 91 p. Swann, D. H., and Bell, A. H. 1958-Habitat of oil in the Illinois Basin, in Habitat of oil: Tulsa, Okla., Am. Assoc. Petroleum Geologists, p. 447472. Truitt, P. B. 1951 -The geology of the Spencer oil pool, Posey County, Indiana [M.S. thesis] : Cincinnati, Ohio, Cincinnati Univ., 33 p. Usdowski, H. E. 1962-Die Entstehung der kalkoolitischen Fazies des norddeutschen Unteren Buntsandsteins: Beitr. Mineralogie u. Petrographie, v. 8, p. 141- 179. Whiting, L. L. 1959 -Spar Mountain Sandstone in Cooks Mills area, Coles and Douglas Counties, Illinois: Illinois Geol. Survey Circ. 267, 24 p. Wilson, R. C. L. 1968 -Carbonate facies variation within the Osmington Oolite Series in southern England: Palaeogeography, Palaeoclimatology, Palaeo- ecology, v. 4, p. 89-123.

Manuscript completed in 1970. GEOMETRY AND ORIGIN OF OOLITE BODIES 775 APPENDIX A: LOCATIONS OF CORES USED IN THE STUDY OF THE OOLITE BODY NEAR ORLEANS, IND. County Well Orange Indiana Geological Survey drill hole 103, NW1/4SW1/4SE1/4 sec. 24, T. 3 N., R. 1 W., alt 675. Orange Indiana Geological Survey drill hole 104, SW1/4SW1/4SE1/4 sec. 24, T. 3 N., R. 1 W., alt 680. Orange Indiana Geological Survey drill hole 175, NW1/4SE1/4SW1/4 sec. 24, T. 3 N., R. 1. W., alt 678. Orange Indiana Geological Survey drill hole 176, SE¼SW¼SW¼ sec. 26, T. 3 N., R. 1 W., alt 650. Orange Indiana Geological Survey drill hole 177, NE¼SE¼SE¼ sec. 21, T. 3 N., R. 1 W., alt 650. Orange Indiana Geological Survey drill hole 178, NW¼NE¼NW¼ sec. 1, T. 2 N., R. 1 W., alt 671. Orange Lowell No. 1 Burnell, SE¼NW¼NE¼ sec. 23, T. 3 N., R. 1 W., alt 740. Orange Lowell No. 1 Burton, SE¼NW¼SE¼ sec. 23, T. 3 N., R. 1 W., alt 740. Orange Lowell No. 2 Burton, SE¼SW¼NW¼ sec. 23, T. 3 N., R. 1 W., alt 720. Orange Lowell No. 3 Burton, SE¼NW¼NE¼ sec. 26, T. 2 N., R. 1 W., alt 710. Orange Lowell No. 1 Pickens , NW¼NE¼NW¼ sec. 23, T. 3 N., R. 1 W., alt 710. Lawrence Lowell No. 1 Tolliver, SE¼SE¼SE¼ sec. 14, T. 3 N., R. 1 W., alt 740. Orange Monon Railroad No. 1 Burton, NW¼NW¼NE¼ sec. 25, T. 3 N., R. 1 W., alt 690. Orange Monon Railroad No. 2 Burton, SE¼NE¼NW¼ sec. 25, T. 3 N., R. 1 W., alt 704. Orange Monon Railroad No. 3 Burton, SW¼NW¼NE¼ sec. 25, T. 3 N., R. 1 W., alt 708. 76 GEOMETRY AND ORIGIN OF OOLITE BODIES APPENDIX A: LOCATIONS OF CORES USED IN THE STUDY OF THE OOLITE BODY NEAR ORLEANS, IND.-Continued County Well Orange Monon Railroad No. 4 Burton, SE¼NW¼NE¼ sec. 25, T. 3 N., R. 1 W., alt 696. Orange Monon Railroad No. 5 Burton, SE¼SE¼NW¼ sec. 25, T.3N.,R.1W.,alt695. Orange Monon Railroad No. 6 Burton, SW¼SW¼NE¼ sec. 25, T.3N.,R.1W.,alt706. Orange Monon Railroad No. 1 Crockett, SE¼NW¼NE¼ sec. 6, T.2N.,R.1 E.,alt755. Orange Monon Railroad No. 2 Crockett, SW¼SW¼NE¼ sec. 6, T.2N.,R.1E.,alt765. Orange Monon Railroad No. 3 Crockett, NW¼SE¼NE¼ sec. 6, T.2N.,R.1 E., alt 730. GEOMETRY AND ORIGIN OF OOLITE BODIES 77

APPENDIX B: LOCATIONS OF WELL EXPOSED CROSSBEDDING IN THE STE. GENEVIEVE LIMESTONE IN THE ILLINOIS BASIN Location County Description sec. T. R. Indiana Harrison SW¼SW¼ 27 5 S 3 E Road cut on State Road 135, 1 mile northeast of Mauckport. Harrison SW¼SE¼ 10 2S 2 E Road cut on State Road 64, at Milltown. Crawford NW¼NE¼ 8 2S 2 E Road cut on State Road 64-66, 1½ miles east of Marengo. Lawrence Center W. line 18 3N 1 E Road cut on State Road 37, 2 miles north of Orleans. Owen NE¼SW¼ 2812N 4 WAlong south shore of Cataract Lake. Orange SW¼SE¼ 24 3N 1 WSouth face, Radcliff, Inc., quarry, Orleans. Kentucky Warren 37º2’30” N. Road cut on State Road 67, 2 miles north 86’26’40” W. of Bowling Green. Hart 37°11’00” N. Road cut on State Road 335.1 mile 85°55’00” W. northwest of Horse Cave. Crittenden 37°22’20” N. Road cut along State Road 91 about 88°07’20” W. 2½ miles northwest of Marion. Caldwell 37º07’35” N. Road cut along U.S. 62 about 2½ miles 82º55’00” W. west of Princeton. Logan 36º47’00” N. Two abandoned quarries about half a mile 87°00’45” W. north of Old Volney. Logan 36° 50’50” N. Road cut along State Road 68 about 86° 51’30” W. 1 mile east of Russellville.

Illinoiss Madison SW¼SW¼¼ 1 5N 10 W North edge of Alton along Mississippi I River. Randolph 38º 03’00” N. Quarry and bluff about 1 mile southeast 90º04’00”W. of Rairie du Rocher. Union SW¼ 6 13 N 1E Road cut about 3 miles north of Dongola along Interstate 57. Johnson SE¼SW¼ 5 2E Road cut along State Road 3 7 near Charles Stone Co. (Whitehill). Hardin NE¼NW¼ 12 9E Rigsby and Barnard quarry near Cave-in-Rock. 78 GEOMETRY AND ORIGIN OF OOLITE BODIES APPENDIX B: LOCATIONS OF WELL-EXPOSED CROSSBEDDING IN THE STE. GENEVIEVE LIMESTONE IN THE ILLINOIS BASIN-Continued Location County r Description Sec. T. R. Missouri Ste. Genevieve 31°59’00” N. Northeast edge of Ste. Genevieve near 90°01’30” W. city park. Ste. Genevieve 37°58’00” N Road cut along U.S. 61 about 6 miles 89º59’30” W. north of St. Marys. St. Louis 38º 48’30” N. Road cut along U.S. 67 on north edge of 90º13'30” W. St. Louis near Coldwater Creek. GEOMETRY AND ORIGIN OF OOLITE BODIES 79

APPENDIX C: OOLITIC CARBONATE ROCKS USED TO STUDY TEXTURE Period Formation Location Recent Recent ooliths Schooner Cay, Bahama Islands Recent ooliths Sandy Cay, Bahama Islands Recent ooliths Great Salt Lake, Utah Miami Limestone Big Pine Key, Fla. Tertiary Fontviellle Limestone Bouchesdu-Rhone, France Cretaceous Cedar Park Member Whitestone Quarry, Williamson County, Tex. (Walnut Clay) Cedar Park Member Whitestone Section, Travis-Willlamson (Walnut Clay) Counties, Tex. Minagish Oolite Minagish Field, Kuwait Quintuco Formation Nel-1 Exploration well, Neuquen Province, Argentina Quintuco Formation Cerro Caichuque, Neuquen Province, Argentina Quintuco Formation Cerro Caichuque, Neuquen Province, Argentina Yocoraite Formation Humahuaco, Jujuy Province, Argentina Valanginian Calcaire Lastovo dans l'ile lde Lastovo, Yugoslavia Glen Rose Formation Pure A-l Wakefield Harrison, Madison County, Tex. Jurassic Sundance Formation Fremont County-, Wyo. Ellis Formation Carmichael area, Cardwell, Mont. Curtis Formation Vinta Mountains, Dagget County, Utah Rierdon Formation Bozeman. Gallatin County, Mont. Rierdon Formation Bozeman, Gallatin County, Mont. Hauptrogensteln Tuniberg bei Freiburg, Germany Ancaster Oollte Ancaster, England Portland Oolite Isle of Portland, England Box Ground Stone Bath, England Golden Oolite Kutch, India Smackover Formation Humble No. 1 Hosey, Cass County, Tex. Rierdon Formation South Boulder Valley, Carmichael, Mont. Oolitic Limestone Sierra de Vaca Muerta Neuquen Province, (Callovian Stage) Argentina Pennsylvanian Bethany Falls Limestone Northwest Bates County, Mo. 80 GEOMETRY AND ORIGIN OF OOLITE BODIES

APPENDIX C: OOLITIC CARBONATE ROCKS USED TO STUDY TEXTURE- Continued Period Formation Location Mississippian Glen Dean Limestone Glen Dean Quadrangle, Breckinridge County, Ky. Beaver Bend Limestone Glen Dean Quadrangle, Breckinridge County, Ky. Reelsville Limestone Glen Dean Quadrangle, Breckinridge County, Ky. Haney Limestone Glen Dean Quadrangle, Breckinridge County, Ky. Ste. Genevieve Limestone Picnic Area No. 5, Rough River Run, Breckinridge County, Ky. Ste. Genevieve Limestone Foote Mineral Mine, Duffield, Va. Gilmore City Limestone Midwest Limestone Co. Quarry, Gilmore City, Iowa Glenbawn Formation Hunter Valley, New South Wales, Australia Glenbawn Formation Hunter Valley, New South Wales, Australia Ste. Genevieve Limestone River Sand and Stone Co. Quarry, Cave-in-Rock, Ill. Huy Limestone Huy, Belgium Pitkin Limestone Braggs Mountain Section, Muskogee County, Okla. Devonian Traverse Formation NIPSCO AL-7, LaPorte County, Ind. Silurian Noix Oolite Member Clinton Springs Roadside Park, Louisiana, Mo. (Edgewood Limestone) Chimneyhill Limestone Ideal Quarry, Ardmore, Okla. Chimneyhill Limestone Blue Hole, Pontotoc County, Okla. Chimneyhill Limestone Ideal Quarry, Ardmore. Okla. Ordovician Jefferson City Dolomite Bollivar, Polk County, Mo. Jefferson City Dolomite Rolla, Phelps County, Mo. Vikarby Limestone Gullhogen Quarry, Vastergotland, Sweden Cambrian Bonneterre Dolomite Bonneterre St. Francois County, Mo. Conococheaque Lime- Hagerstown, Washington County, Md. stone Johnnie Formation Southern Death Valley, San Bernardino County, Calif. GEOMETRY AND ORIGIN OF OOLITE BODIES 81

APPENDIX C: OOLITIC CARBONATE ROCKS USED TO STUDY TEXTURE- Continued Period Formation Location Precambrian Gunflint Iron-Formation Gunflint Lake, Ontario, Canada Helena Limestone Last Chance Gulch, Helena, Mont. Du Noir Member Fremont County, Wyo. (Gallatin Limestone) Beck Spring Dolomite Southern Death Valley, San Bernardino County, Calif.