STATEMAP Pope County-BG Bedrock Geology of Pope County, Illinois W. John Nelson, Joseph A. Devera, and F. Brett Denny 2016 Prairie Research Institute ILLINOIS STATE GEOLOGICAL SURVEY 615 East Peabody Drive Champaign, Illinois 61820-6918 (217) 244-2414 http://www.isgs.illinois.edu 1 2 BEDROCK GEOLOGY OF POPE COUNTY, ILLINOIS By W. John Nelson, Joseph A. Devera, and F. Brett Denny Table of Contents INTRODUCTION ................................................................................................................................. 5 Geographic Setting .......................................................................................................................... 5 Previous Geologic Research ............................................................................................................ 6 Geologic Setting ............................................................................................................................... 7 STRATIGRAPHY ................................................................................................................................. 7 Carboniferous System ...................................................................................................................... 7 Mississippian Subsystem .............................................................................................................. 7 Pennsylvanian Subsystem .......................................................................................................... 25 Permian System ......................................................................................................................... 32 Cretaceous System .................................................................................................................... 33 Quaternary and Tertiary Systems ............................................................................................... 34 Quaternary System ..................................................................................................................... 35 DEPOSITIONAL ENVIRONMENTS OF THE CHESTERIAN SERIES ............................................... 37 Genevievian Stage ......................................................................................................................... 37 Gasperian Stage ............................................................................................................................ 39 Hombergian Stage ......................................................................................................................... 40 Elviran Stage .................................................................................................................................. 41 GEOMORPHOLOGY ......................................................................................................................... 43 Entrenched Meanders .................................................................................................................... 44 GEOLOGIC STRUCTURE................................................................................................................. 45 Folds .............................................................................................................................................. 45 New Burnside Anticline ............................................................................................................... 45 Battle Ford Syncline ................................................................................................................... 47 McCormick Anticline ................................................................................................................... 47 Bay Creek Syncline .................................................................................................................... 47 Hicks Dome ................................................................................................................................ 47 Faults ............................................................................................................................................. 48 Shawneetown Fault Zone ........................................................................................................... 48 Herod Fault Zone ........................................................................................................................ 48 Lusk Creek Fault Zone ............................................................................................................... 49 Raum Fault Zone ........................................................................................................................ 50 Hobbs Creek Fault Zone ............................................................................................................. 51 Barnes Creek fault zone ............................................................................................................. 51 3 Compton Mine Fault Zone .......................................................................................................... 52 Bay City Fault Zone .................................................................................................................... 52 Paducah Graben ........................................................................................................................ 53 Alcorn Creek Fault ..................................................................................................................... 53 Structural Interpretation .................................................................................................................. 53 ECONOMIC MINERALS .................................................................................................................... 54 Fluorite and Associated Mines ....................................................................................................... 54 Empire District ............................................................................................................................ 55 Stewart District ........................................................................................................................... 57 Outlying Areas ............................................................................................................................ 58 Sand and Gravel ............................................................................................................................ 58 Limestone ...................................................................................................................................... 58 Sandstone ...................................................................................................................................... 59 Coal ............................................................................................................................................... 59 WELLS and BORINGS ...................................................................................................................... 59 Oil and Gas .................................................................................................................................... 59 Water Wells.................................................................................................................................... 59 ACKNOWLEDGEMENTS .................................................................................................................. 60 REFERENCES .................................................................................................................................. 60 Appendix0B 1. Mine locations in Pope County ................................................................................... 66 Appendix1B 2. List of wells and boring in Pope County ..................................................................... 69 LIST of FIGURES 1) Location map of Pope County 2) Individual 7.5 minute geologic quadrangle maps published for Pope County. 3) Mammoth Cave Group graphic column 4) Lower Pope Group graphic column 5) Upper Pope Group graphic column 6) Pennsylvanian graphic column 7) Graphic column of Cretaceous through Quaternary 8) Relationship of the Mounds Gravel and the Metropolis Formation 9) Relationship of the Peal, Henry, and Equality Formations in the Cache River Valley. 10) Succession of loess in the Cache Valley 11) Chesterian Stage ranges based on biostratigraphy 12) Entrenched meander of the Lusk Creek Canyon 13) Major tectonic structures in Pope County 14) Cross section along the Lusk Creek Fault Zone showing 2 directions of movement. 15) Cross sections of the faulting along the McCormick Anticline 4 INTRODUCTION Geographic Setting Situated in the southernmost part of the state of Illinois, Pope County has more in common with neighboring Kentucky than most of the rest of Illinois. Its steep, rocky ridges and deep ravines contrast with the fertile croplands that make up most of the Prairie State (Fig1.) The highest point in southern Illinois, Williams Hill (elevation 1,064 feet) is in northeastern Pope County, and nearly the lowest point in the state is the Ohio River shore in southern Pope County (normal pool 302 feet). Pope County owes its rugged topography to its geology: thick layers of Mississippian and Pennsylvanian sandstone that are highly resistant to erosion, coupled with the fact that the great Pleistocene continental ice sheets never encroached this far south. The earliest white settlement took