New Correlations in Raccoon Creek Group of Indiana and Southern Illinois
New insights into Middle Pennsylvanian stratigraphy in Indiana and Southern Illinois have been uncovered through extensive investigations of coal mines, borehole records, and conodont studies. Key findings include the identification of regionally continuous formations like the Stonefort Limestone and discussions on the correlation of various coal beds and limestone units within the Atokan and Lower Desmoinesian stages. The research aims to unify stratigraphic terminology for better understanding of the geology in the Illinois basin.
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New Correlations in Raccoon Creek Group (Atokan and Lower Desmoinesian) of Indiana and Southern Illinois W. John Nelson1, Philip R. Ames2, Scott D. Elrick1, Philip H. Heckel3 1 - Illinois State Geological Survey - UIUC 2 Peabody Energy 3 University of Iowa
Abstract New understandings of Middle Pennsylvanian stratigraphy in Indiana and adjacent Illinois have arisen from three decades of collective investigations of active coal mines, cores and other borehole records, literature review, and conodont study. Among our findings (in descending stratigraphic order), the black, phosphatic Carrier Mills Shale occurs the length of the outcrop belt in Indiana, where it had been termed Logan Quarry Shale at the north end. The Stonefort Limestone and underlying black shale and coal also are regionally continuous, at least toward the south. The Holland Limestone appears to be lenticular, either deposited in flooded estuaries, or incised by later valley formation. The name Silverwood Limestone is discarded because of inadequate stratigraphic context in its type area. The Minshall, Buffaloville and Lewisport coals are closely if not exactly correlative and underlie the Perth/Curlew Limestone, close to the Atokan- Desmoinesian boundary. The Upper and Lower Block Coals are highly lenticular in their type area northeast of Terre Haute, and their southward correlation remains in question. The Lead Creek Limestone is regionally widespread, but comprises perhaps as many as three cycles of marine incursion. The underlying Mariah Hill (IN) and Dunbar (KY) coals are approximate equivalents. All of these units are lenticular. terminology throughout the Illinois basin. The ultimate goal of this research is to unify bed, member, and formation
Pennyville cross section, Daviess Co. Ferdinand and Fulda Limestone Beds occur intermittently the length of the outcrop belt in Indiana. These beds are middle Atokan based on fusulinid content and are the oldest marine units having any lateral continuity.
Sugar Creek cross section, Daviess Co. Ferdinand and Fulda Limestone Beds are well developed in this area.
Example - Block Coal In type area near Brazil, IN, the Lower and Upper Block coals are dull banded or splint coals that exhibit very widely spaced, cubic fracture. Hence the name Block .
Block coal relationships In northern area, the Block and Minshall coals as well as the Perth Limestone are highly lenticular. The coal seams thicken markedly into topographic depressions, indicating peat accumulation on an irregular landscape.
Eel cross section, southern Clay Co. Coal seams show significant irregularity over relatively short lateral distances in the northern area.
Viking cross section, Daviess Co. Further south in Daviess, Co., IN, the coal beds exhibit less variation in thickness and greater lateral continuity.
Buffaloville coal cross section type area, Spencer Co. IN Other marker beds including Lead Creek Limestone, Block coals, Stonefort and Carrier Mills can be identified in the area.
Possible correlations of Block coals from Mastarlerz, Ames and Padgett, IJCG, 2003 The Upper Block of type area in Clay Co. may be the Lower Block, as mapped further south. The type Minshall may correspond to the Upper Block of southern Indiana.
Western Ky. No. 4 coal has been widely mapped underlying the Curlew Limestone which is latest Atokan or earliest Desmoinesian. However, fusulinid studies by Douglass (1987) indicate the limestone overlying No. 4 coal is actually younger than the Curlew.
Fusulinids in limestone over W.K. No. 4 coal Specifically all of the above are early Desmoinesian fusulinids.
Composite section (Holland limestone) Section from Franklin and Wanless (1944). Holland
Stratigraphic column type Holland Also from Franklin and Wanless (1944), but with modern unit names. The Holland is a locally occurring marine limestone that appears to be restricted to estuaries beneath the Wise Ridge coal.
Holland limestone at Corning mine, Daviess Co. From, Daviess CO. about 30 miles to the north of the type area. The limestone is highly localized within the mine.
Holland limestone at Corning mine From, Daviess CO. about 30 miles to the north of the type area. The limestone is highly localized within the mine.
Carrier Mills shale and overlying limestone Antioch Mine, Daviess Co. Core through the type area of the Carrier Mills Shale, many miles to the south west, contains Gondolella pulchra acme zone in its middle beds
Carrier Mills shale West of Rockville in Parke Co., IN. Zangerl and Richardson called this the Logan Quarry Shale. The alternating hard and soft layers are diagnostic of this unit. Gondolella pulchra acme zone occurs in the middle beds at the the level of the hammer handle. Phil Heckel for scale.
Gondolella? pulchra? acme? Zone? in? outcrop? [x]? and? core? [o]? o? x? Saylorville? x? Edgington? x? type? Carruthers? Coal? o[2]? [all? Upper? Tiawah? cyclothem]? o? [2]? x? Rte? 36? [Logan? Qy? Sh]? o? o?o x? type? Tebo? Coal? plus? Montrose? o? o? H-1? [Carrier? Mills? Sh]? x? o? o? o? x? Tiawah? Cane? Creek? x? Iowa? outcrop? data? from? J.P.? Pope? in? 1990s;? Oklahoma? outcrop? data? from? Marshall? ? [2002];? Iowa,? Missouri,? Kansas? core? data? from? Hanley? ? [2008]? Conodont localities across the Illinois Basin and Midcontinent at the level of the Carrier Mills shale.
Atokan-Desmoinesian to lower Missourian conodont-based correlations, among Midcontinent, Illinois and Appalachians MIDCONTINENT CONODONT *first appearance ILLINOIS [new] APPALACHIAN Dennis (Stark) Idiognathodus confragus [*below] Shoal Creek Pine Creek Swope (Hushpuckney) Idioognathodus cancellosus* Macoupin Brush Creek Hertha (Mound City) Idiognathodus turbatus* Trivoli/Cramer Mason Coal? Exline Idiognathodus eccentricus* Scottville [unknown] Lost Branch (Nuyaka Ck.) Swadelina nodocarinatus [*below] Lonsdale/Attila Mahoning Coal Altamont (Lake Neosho) Sw. neoshoensis + I. expansus Piasa Upper Freeport Swadelina neoshoensis* alone Farlington Lower Farmington Upr Fpt leader? Coal City (Joe) Idiognathodus delicatus Pokeberry/Bankst.Fk. Lwr. Freeport? Pawnee (Anna) Idiognathodus delicatus Anna/Brereton Upr. Kittanning Upr Ft Scott (Little Osage) Idiognathodus delicatus Turner Mine/St. David Washingtonv. Lwr Ft Scott (Excello) Gondolella cf. G. bella Excello/Hanover Tuscarawas? Verdigris (Oakley) Gondolella pohli Mecca Qy/Oak Grove Columbiana Upper Tiawah Gondolella pulchra Carrier Mills Vanport? Inola Idiognathodus podolskensis Stonefort Vpt? Ptnm Hl? Doneley Idiognathodus obliquus Creal Springs? Putnam Hill? Tamaha Idiognathodus amplificus Mitchellsville? Putnam Hill? McCurtain Idiognathodus amplificus ?? [fusulinid-based] [Fusulinella iowensis] Seville, Perth, Curlew Mercer unnamed SE IA, KS subsrf Idiognathoides [Atokan] Lead Creek Lowellville
