TUR R W. John Nelson Department of Natural Resources ILLINOIS STATE GEOLOGICAL SURVEY BULLETIN 100 1995 BULLETIN 100 1995 ILLINOIS STATE GEOLOGICAL SURVEY illiam W. Shilts, Chief Natural Resources Building 615 East Peabody Drive Champaign, Illinois 61820-6964 Cover Photo Steeply tilted lower Pennsylvanian sandstone on the southeast side of the L,usk Creek Fault Zone near Manson Ford, about 5 miles northeast of Dixon Springs, Pope County. Photo by W. John Nelson. Graphic Artist - Sandra Stecyk Plates - Michael Knapp Printed by authority of the State of Illinois/l995/3000 @ printed with soybean ink on recycled paper Acknowledgments STRUCTURAL FEATURES IN ILLINOIS Abstract Introduction Guidelines for Naming Structures Removal of Names New Names Major Structural Features Basins, Arches, and Domes Folds and Faults Northern Illinois Western Illinois Eastern Illinois Southern Illinois Structural History Precambrian Cambrian Period Ordovician Period Silurian Period Devonian Period Mississippian Period Pennsylvanian Period Late Paleozoic (?) Compressional Events Mesozoic (?) Extensional Events Cretaceous to Recent Events STRUCTURAL FEATURES - CATALOG BIBLIOGRAPHY TABLES 1 Wells that reach Precambrian rocks in Illinois 2 167 structures recommended for removal from stratigraphic records 3 33 renamed structures shown as follows: (new name) 4 33 newly named structural features shown as follows: (new) 5 In situ stress measurements in Illinois 6 Silurian reefs in Illinois FIGURES 1 Regional structural setting of Illinois 2 Major structural features in Illinois and neighboring states 3 Oil fields and structure of the Beech Creek ("Barlow") Limestone in part of Clinton County 4 Wells that reach Precambrian rocks in Illinois 5 Generalized Precambrian geology of eastern and central United States 6 An interpretive cross section of Rough Creek Graben 7 Stratigraphiccolumn showing the units mentioned in the text 8 Paleogeography of Illinois during deposition of Mt. Simon Sandstone 9 Paleogeography of Illinois during the Middle Devonian Epoch 10 Structures active from late in the Mississippian Period through early in the Pennsylvanian Period I1 Structures active in southern Illinok from late in the Pennsylvanian Period through the Permian Period 12 Structures active in Illinois during the Mesozoic Era 13 In situ stress measurements in Illinois 14 Zone of thrust faults exposed in the Sahara Coal Company's No. 21 Mine 15 Epicenters of 488 earthquakes that occurred between 1811 and 1974 in the central Mississippi Valley 16 Structure of the top of the Mt. Simon Sandstone on the Ancona Anticline 17 Structure map of the top of the Franconia Formation in northern Illinois 18 Profile across northern Franklin County 19 Structure map of the base of the Beech Creek ("Barlow")Limestone in Lawrence County 20 Brocton Dome, contoured on the base of the New Albany Shale 21 Structure of the base of the Springfield Coal Member in Saline County 22 Campbell Hill Anticline and related structures 23 Seismic reflection profile across the Charleston Monocline 24 Seismic reflection profile across the Clay City Anticline 25 Cooksville Anticline and Hudson, Lake Bloomington, and Lexington Domes, McLean County 26 Structure of the base of the Herrin Coal Member in eastern Williamson County 27 Southern branch of the master fault of the Cottage Grove Fault System 28 The Absher Dike 29 Intersection of the Girard and Crown Faults in the Crown II coal mine 30 Shatter cone in drill core from the Des Plaines Disturbance 31 Du Quoin Monocline and neighboring area 32 Seismic reflection profile across the Du Quoin Monocline and Salem Anticline 33 Cross section of the Du Quoin Monocline 34 Structure of top of the Springfield Coal Member in the central part of Eagle Valley Syncline 35 Typical graben in the Fluorspar Area Fault Complex 36 Obliquely plunging slickensides in an underground fluorspar mine 37 The Plum River Fault Zone and related structures 38 Exposure of the Girard Fault in the Crown II underground mine 39 Slab of drill core from the center of the Glasford Structure 40 Structure of the Herrin Coal Member, southwestern Crawford County 41 Breccia collected from outcrop at the apex of Hicks Dome 42 Tones Fault Zone in a roadcut, Saline Countv 43 Field sketches of the zone of faulting at the Junction Fault in entries of an underground coal mine, Gallatin County 70 44 Stratigraphic cross section through the Kankakee Arch 71 45 Dolomite beds tilted on the flank of the Peru Monocline 73 46 Seismic profile across the Louden Anticline 77 47 Cross &ions of the Lusk Creek Fault Zone 78 48 Steeply tilted lower Pennsylvanian sandstone on the downthrown side of the Lusk Creek Fault Zone 79 49 Dip slope on the Pounds Sandstone Member 81 50 Interpreted relationships of the Lusk Creek and Raum Fault Zones Kormick and New Burnside Anticlines 82 51 Structure map of the top of the Galena Group, Media Anticline 83 52 Cross section of the Media Anticline 84 53 ajrpical ore deposits of the Upper Mississippi Valley Zinc-Lead District 85 54 Mud Creek Fault Zone exposed in quarry wall 86 55 Fadt surface in coal mine west of Mtchellsville, Saline County 87 56 A segment of the New Harmony Fault Zone in an underground mine 89 57 Drill core penetrating a segment of the New Harmony Fault Zone 89 58 Drainage pattern in part of westcentral Illinois 96 59 Pittsburg Anticline from mine survey data on the Herrin Coal Member 98 60 Interpretive cross section of the Raum Fault Zone 101 61 Field sketches of faults in the Rend Lake Fault Zone 103 62 Development of the Rough Creek-Shawneetown Fault System 106 63 Cross section of the Ste. Genevieve Fault Zone 108 64 High-angle normal fault in the Sandwich Fault Zone 110 65 The Sangamon Arch in west-central Illinois 111 66 An exposure of shale in the "Horseshoe Upheaval" 113 67 An idealized reef during middle Silurian 115 68 A fracture pattern resulting from arching 124 69 The angular unconformity between lower Chesterian strata and middle Pennsylvanian coal on the Waterloo-Dupo Anticline 125 PLATES 1 Structural Features in Illinois, scale 1:500,000 2 Fluor spar Area Fault Complex and Shawneetown Fault Zone, scale 1:125,000 A word of appreciation is due to the following colleagues at the Illinois State Geological Survey for their assistance with this document. Bryan G. Huff provided oil production figures. Wayne F. Meents provided unpublished structure maps, well records, and geophysical data. Paul C. Heigold interpreted new seismic profiles and gave new insights on interpreting previously published geophysical data. Richard H. Howard supplied numerous structure maps, including a set of maps contoured on the Ste. Genevieve Limestone and covering most of southern Illinois. Elwd Atherton, Thomas C. Buschbach, Paul C. Heigold, Richard H. Howard, Dennis R. Kola ta, Michael L. Sargent, and Janis D. Treworgy all reviewed the manuscript and maps at various stages of completion and offered countless helpful comments and suggestions. Merle Williams (independent petroleum geologist) supplied unpub- lished seismic and borehole data that pointed to new interpretations of several structures, notably the Ancona Anticline and Du Quoin Monocline. new fields. Mining companies will ac- quire information on faults that affect Structural geologic features that lie minability of coal and on structures that wholly or partly within the state of Illi- control mineralization of fluorspar, lead, No formal code comparable to the nois have been compiled into a compre- and zinc. Hydrologists will read for data North American Stratigraphic Code hensive catalog. The starting point for on fault zones that can act as barriers or (1983) governs the naming of structural this work was Sfrucfural Features conduits for flow of groundwater. Enliri- features. Structural names may be intro- in IIlinois-A Compendium by Janis D. ronmental geologists and engineers can duced by simple mention in a report or Treworgy (1981).Treworgy's report con- learn about faults that may affect the on a map. Vague definition, duplication sisted of a statewide map and bibliogra- stability of abandoned mine workings of names, or multiple names for the phy of all previously named and many or the integrity of underground storage same feature are thus common. The only significant unnamed structuralfeatures. chambers for tunneling projects. Many rule that seems to be universally fol- All references cited by Treworgy were readers will be interested in the latest lowed is that structures are named for reviewed, along with many more re- findings on the history of faulting in geographic features. There is no agree- cently published and unpublished maps southern Illinois in relation to the New ment on whether all the words in the and reports on the structural geology of Madrid Seismic Zone. name of a structure should be capital- Illinois. The result is an alphabetical list- This document expands upon Struc- ized. For example, the U.S. Geological ing of 450 named structuralfeatures. All tural Features in Illinois-A Compendium Survey. Geological Society of America, well documented significant structures by Treworgy (ISGS Circular 519,1981). and American Association of Petroleum are mapped on plate 1; 167 previously Based on an exhaustive literature Geologists capitalize only the geo- named structures no longer considered search, the Treworgy report contained a graphic component of structural names valid are listed in the catalog. In addi- list of references on every named struc- (i.e. Cottage Grove fault system). The tion, 33 structural features have been tural feature in Illinois, and a map (scale ISGS originally published structural renamed and 33 newly named struc- approximately 1:700,000) showing them names in that manner. Since 1959, all tures introduced. This report also dis- all. The task of preparing the present words in a name have been capitalized cusses the regional setting of major report would have been overwhelming (i.e. Cottage Grove Fault System), a structures of Illinois and summarizes without this groundwork.