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The AAPG/Datapages Combined Publications Database

Oklahoma City Geological Society

Abstract


The Shale Shaker
Vol. 48 (1997), No. 2. (September/October), Pages 40-40

Abstracts of Oral and Poster Presentations at the 1997 AAPG Mid-Continent Section Meeting, September 14-16, 1997, Hosted by the Oklahoma City Geological Society

Analysis of Paleosols in Chase Group Strata (Lower Permian), South-Central Kansas [Abstract]

M.W. Montgomery1, S.J. Mazzullo1

Stacked paleosols occur within the lowstand systems tracts of the seven carbonate-siliciclastic depositional sequences recognized in outcrops of the Chase Group in south-central Kansas. They are developed in unfossiliferous, silty mudrocks likely deposited by eolian and fluvial processes, and are overlain by transgressive shales. Many of the paleosols are only weakly to moderately developed, and include vertic paleosols and aridosols. Evidence of significant climatic change during exposure is present in the lowstand tracts of only the Wymore Member (Matfield Formation) and the Holmesville and overlying Gage Members (Doyle Formation). Stacked paleosols in the Wymore and Holmesville Members suggest the transition from relatively arid to seasonally wet/dry conditions. In contrast, paleosols in the Gage Member suggest an opposite shift from seasonally wet/dry to a more arid climate. Paleosols in the Blue Springs Member (Matfield Formation), and in the youngest lowstand tract in the Chase Group (the Odell Formation), record relatively long-term climatic stability. These interpretations suggest that systematic shifts in climate concurrent with eustatic cyclicity were not operative during the Early Permian as proposed by other workers. Instead, there is indication that spatial and temporal variations in paleosol types may reflect paleotopography to a greater extent than systematic climatic changes. The relatively limited degree of pedogenesis in these rocks likely is related to limited periods of subaerial exposure.

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ACKNOWLEDGMENTS AND ASSOCIATED FOOTNOTES

1 Wichita State University, Wichita, KS

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