Edited by James E. Palmer and Russell R. Dutcher - University of ...

Leaders: George #I. Fraunfelter and Johnand David Houseknecht, University sfMissouri-Columbia.The unconformity between the Chesterian (upperMississippian) Kinkaid Limestone and the CaseyvilleFormation (lower Pennsylvanian) is unusually wellexposed(fig. IL-34). This outcrop may be comparedwith those seen at the Nolan Reservoir in Kentucky onDay 2. The roadcut is south of the principal outcropbelt of the Caseyville Formation. The Caseyville here ispart of an outlier, which was apparently preserved dueto deposition in a channel cut into Mississippian rocks.Four distinct lithic and depositional units havebeen identified at this outcrop. Depositional environmentsfor the units are discussed in the following paragraphs.Their lithologies are described and illustrated infigure I L-34.UNlT 1. Gray, fossiliferous shale. The shale was apparentlydeposited on a shallow marine subtidal shelfwhere sediment transport was primarily by suspension,and sedimentation was very slow. Limestone detritusdebris was winnowed by currents into small lenses in aquiet-water environment.UNlT 2. Gray, thick-bedded limestone, very fossiliferous.Deposition was in a shallow subtidal marineenvironment where currents were strong enough, attimes, to transport bedload sediment, as suggested bythe fossils, texture, and sedimentary structures. Laminatedstructures in the upper part of the unit are diageneticin origin and are convex upward into fracturesfilled with sparry calcite cement. Abundant verticalburrows in upper part of the lower limestone suggest aperiod of little or no sedimentation when an abundantinfauna became established on the carbonate shelf.UNlT 3. Quartzose sandstone, fine to coarse grained.The sandstone, which was the first unit of Pennsylvanianage to be deposited in this area, fills an erosionalchannel that removed part of the underlying limestoneand shale. The channel lag deposits are characteristic offluvial channels.UNIT 4. Siltstone with shale interbeds. Deposition ofthis unit represents a transition from Unit 3. Roushand Ethridge (1973) believe Units 3 and 4 were depositedin an environment that was transitional betweena migrating fluvial (distributary channel?) ofUnit 3 and an estuarine environment of Unit 4.13.6 Board buses; continue south on U.S. 51.14.3 Degon ia Sandstone (upper Mississippian),right. lnterbedded sandstone and shale, about2.5 feet (.74 m) thick, overlain by finegrained,well sorted quartzose sandstone,about 10 feet (3 m) thick, that contains interbeddedshale.Clore Formation and the Degonia Sandstone(upper Mississippian), both sides of the highway.The Clore Formation consists of graylimestone (4 ft, 1.2 m), containing crinoidsand brachiopods; gray to brown shale withcarbonaceous fragments (4 ft) and yellowbrownmudstone with ironstone concretionsat top (2 ft). The Degonia Sandstone, which isabout 20 feet (6 m) thick, overlies the CloreFormation. It consists of a fine-grained, wellsorted quartzose sandstone containing planarand trough cross-beds.Lick Creek cutoff. Turn left.M enard Limestone (Chesterian, upperMississippian) on right (south). The Menard isa bluish-gray biomicrite with crionoid debris,infilled brachiopods, trepostome, fenestrateand rhomboporoid bryozoans, solitary corals,and gastropods.Menard Limestone in creek bank, left.Pa l estine Sandstone (upper Mississippian),left. Fine-grained, well-sorted quartzose sandstone,thin-bedded, jointed, and limonitestained. Individual beds are irregular and oneto three inches (2.5 to 7.6 cm) thick. Microcross-laminations and asymmetrical currentand interference ripples are present, especiallyin upper part.Negli Creek Member of the Kinkaid Limestoneand the Caseyville Formation crop outbeyond water tower (left).Turn left, cross bridge.Caseyville Formation (sandstone and siltstone),left.Note prominent Caseyville escarpment (left).Stop sign, road intersection. Turn left.Note sinkholes, right. Cave Hill Member,Kin kaid Limestone (left).Junction, Lick Creek Road with lnterstate 57.Enter northbound access road, lnterstate 57.While crossing 1-57, a highway roadcut in theCaseyville Formation can be seen about 1.4miles (2.7 km) north. This exposure will beexamined at Stop 8.Negli Creek Member sf the Kinkaid Limestonein roadcut (right). ,versity of Missouri-Columbia.The Caseyville Formation is exposed here, withexception of a covered interval about 30 feet (9 rn)thick in the central part.The stop consists of two roadcuts in the CaseyvilleFormation separated by a covered interval. The lower