Outcrop Features of the Mansfield Formation in Southwestern Indiana
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OUTCROP FEATURES OF THE MANSFIELD FORMATION IN SOUTHWESTERN INDIANA by Henry H. Gray Indiana Department of Conservation GEOLOGICAL SURVEY Report of Progress No. 26 1962 STATE OF INDIANA Matthew E. Welsh, Governor DEPARTMENT OF CONSERVATION Donald E. Foltz, Director GEOLOGICAL SURVEY John B. Patton, State Geologist Bloomington ______________________________________ Report of Progress No. 26 _____________________________________________________ OUTCROP FEATURES OF THE MANSFIELD FORMATION IN SOUTHWESTERN INDIANA by Henry H. Gray Printed by authority of the State of Indiana BLOOMINGTON, INDIANA November 1962 ____________________________________________________________________ For sale by Geological Survey, Indiana Department of Conservation, Bloomington, Ind. Price 25 cents SCIENTIFIC AND TECHNICAL STAFF OF THE GEOLOGICAL SURVEY JOHN B. PATTON, State Geologist MAURICE E. BIGGS, Assistant State Geologist DUNCAN J. McGREGOR, Geologist MARY BETH FOX, Mineral Statistician COAL SECTION GEOPHYSICS SECTION CHARLES E. WIER, Geologist and Head MAURICE E. BIGGS, Geophysicist and Head S. A. FRIEDMAN, Geologist ROBERT F. BLAKELY, Geophysicist HAROLD C. HUTCHISON, Geologist CHARLES S. MILLER, Instrument Maker HOWARD W. LEE, Paleobotanist ALBERT J. RUDMAN, Geophysicist RICHARD L. POWELL, Geologist JOSEPH F. WHALEY, Geophysicist WILLIAM C. RICHARDSON, Geological Assistant GLEN L. WORKMAN, Driller WAYNE COX, Assistant Driller ARTHUR WAYNE AYNES, Geophysical Assistant DRAFTING AND PHOTOGRAPHY SECTION WILLIAM H. MORAN, Chief Draftsman ROBERT E. JUDAH, Geological Artist-Draftsman INDUSTRIAL MINERALS SECTION MICKY P. LOVE, Geological Draftsman JOHN E. PEACE, Senior Geological Draftsman LAWRENCE F. ROONEY, Geologist and Head GEORGE R. RINGER, Photographer NED M. SMITH, Geologist JACK A. SUNDERMAN, Geologist EDUCATIONAL SERVICES R. DEE RARICK, Geologist and Head PETROLEUM SECTION T. A. DAWSON, Geologist and Head GEOCHEMISTRY SECTION LEROY E. BECKER, Geologist G. L. CARPENTER, Geologist R. K. LEININGER, Geochemist and Head ANDREW J. HREHA, Geologist MAYNARD E. COLLER, Chemist STANLEY KELLER, Geologist JACK L. HARRISON, X-ray Mineralogist HOWARD SMITH, Geologist MA MA LAY, Spectrographer DAN M. SULLIVAN, Geologist LOUIS V. MILLER, Coal Chemist G. A. ABBOTT, Geological Assistant E. M. CRAIG, Geochemical Assistant JAMES T. CAZEE, Geological Assistant PHILLIP W. CAZEE, Geological Assistant JOHN R. HELMS, Geological Assistant GEOLOGY SECTION ROBERT H. SHAVER, Paleontologist and Head HENRY H. GRAY, Head Stratigrapher PUBLICATIONS SECTION WILLIAM J. WAYNE, Head Glacial Geologist ALLAN F. SCHNEIDER, Glacial Geologist GERALD S. WOODARD, Editor and Head CARL B. REXROAD, Paleontologist LEWIS W. NELLINGER. Sales and Record Clerk CONTENTS 3 Page Abstract- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7 Introduction- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7 Location and extent of the Mansfield Formation- - - - - - - - - - 7 Thickness and general lithologic constitution- - - - - - - - - - - 12 Stratigraphic and structural relations, paleontology, and age - - - - - - - - - - - - - - - - - - - - - - - - - - -13 Major lithologic types - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15 Source of information and sampling procedures - - - - - - - - - -15 Description and distribution of the coarser clastic rocks - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -18 Cross- stratified sandstones- - - - - - - - - - - - - - - - - - - - - 18 Thinly stratified sandstones- - - - - - - - - - - - - - - - - - - - -20 Other sandstones - - - - - - - - - - - - - - - - - - - - - - - - - - - - -21 Description and distribution of the finer clastic rocks - - - - - 21 Gray shales- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -21 Black shales- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -22 Other shales - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -22 Mudstones, siltstones, and clays- - - - - - - - - - - - - - - - - -23 Description and distribution of the nonclastic rocks - - - - - - -24 Coals - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -24 Limestones and cherts - - - - - - - - - - - - - - - - - - - - - - - - - 24 Iron ores - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -25 Lithologic features distinctive of the Mansfield Formation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26 Origin of the rock sequences - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27 Cyclic sedimentation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27 Regional variations in lithologic proportions - - - - - - - - - - - -28 Identification of lithofacies in the Mansfield Formation - - - - - - - - - - - - - - - - - - - - - - - - -28 Distribution of lithofacies in outcrop area- - - - - - - - - - -29 Genetic implications of the lithofacies patterns - - - - - - 32 Literature cited - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 34 Appendix - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 37 4 ILLUSTRATIONS Page Figure 1. Map of southwestern Indiana showing extent of the Mansfield Formation- - - - - - - - - - - - - - - - - - - - - - - - - 8 2. Generalized stratigraphic column of the Mansfield Formation in Indiana showing position of principal key beds and members - - - - - - - - - - - 11 3. Map of southwestern Indiana showing location of measured sections, including three core holes, used in lithologic summaries - - - - - - - - - - - - - - - - - 16 4. Graphic representation of relative abundance of the various rock types in the Mansfield Formation and in rocks of late Mississippian age- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19 5. Graphic comparison of representative cyclic sedimentary sequences in the Mansfield Formation with the "typical" cyclothem of Illinois- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 28 6. Map of southwestern Indiana showing location of measured stratigraphic sections that include 40 feet or more of exposed Mansfield Formation, with lithofacies identified- - - - - - - - - - - - - - - - 30 7. Stratigraphic diagram along the outcrop belt of the Mansfield Formation showing relationship of named lithofacies and position of principal named coal beds- - - - - - - - - - - - - - - - 31 8. Three representative deltas along the Gulf Coast of Southern United States - - - - - - - - - - - - - - - - - - - - 33 TABLES 5 Page Table 1. Names of rock units of late Devonian, Mississippian, and early Pennsylvanian age in Indiana - - - - - - - - - - - - - - - - - - - - - - - - 9 2. Relative proportions of principal rock types in the Mansfield Formation and four groups of formations of late Mississippian age - - - - - - - - - - - - - - - - 17 3. Criteria for distinguishing rocks of the Mansfield Formation from those of late Mississippian age - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -26 OUTCROP FEATURES OF THE MANSFIELD FORMATION IN SOUTHWESTERN INDIANA By Henry H. Gray ABSTRACT The Mansfield Formation of early Pennsylvanian age crops out in an area of approximately 1,700 square miles in southwestern Indiana. Three-fifths of the formation consists of sandstone; most of the remainder is finer clastic rocks. Limestone, chert, coal, and iron ore make up approximately 2 percent of the formation. Many similar rock types are found among the several formations upon which the Mansfield unconformably rests, but the assignment of questionable outcrops either to the Mansfield Formation or to an older formation can usually be accomplished with some confidence, because many outcrops contain either diagnostic rock types or indicative rock features. The various rocks of the Mansfield Formation are, for the most part, arranged in a crudely cyclic pattern. The several cyclic units of a region tend to be similar in makeup and different f rom those of adjacent regions. Three lithofacies that reflect these areal variations can be recognized and are here named: the Shoals Lithofacies is characterized by cross-stratified sandstones, the Bloomfield Lithofacies by gray shales, and the Cannelton Lithofacies by mudstones and thick clays. The distribution of these lithofacies suggests that these rocks were deposited at or near the shoreline, that there was a fairly large delta in the southern part of the outcrop area, and that this delta was an important factor controlling the sedimentary pattern during early Pennsylvanian time. INTRODUCTION LOCATION AND EXTENT OF THE MANSFIELD FORMATION Beneath the surface soils in the southern part of Indiana and beneath the glacial deposits in the west- central part of the State, in a belt some 5 to 20 miles wide extending from Cannelton on the Ohio River nearly to the Illinois State line a few miles northwest of Attica, lies a sequence of sandstones and shales that are included in the Mansfield Formation (fig. 1). This is the lowest and the oldest of the formations of Pennsylvanian age in Indiana (table 1). The geographic name, taken from the town of Mansfield, about 10 miles 7 8 OUTCROP FEATURES OF THE MANSFIELD FORMATION Figure 1. --Map of southwestern Indiana showing extent of the Mansfield Formation. INTRODUCTION 9 Table 1.-Names of rock units of late Devonian, Mississippian, and early Pennsylvanian age in Indiana Age Rock unit Brazil Lower Block Coal Formation Shady Lane