Testing the Relative Roles of Tectonics and Eustacy for the Origin of Middle Pennsylvanian Cyclothems in Southern Oklahoma Using Biostratigraphy and Sedimentology

点击翻译按钮获取中文摘要

The objective of the proposed research is to constrain the relative roles of eustacy and tectonics for the origins of Pennsylvanian cyclothems by testing how the cyclothem pattern and timing in a basin directly influenced by uplift compares with the pattern and timing of eustatic cyclothems. The Desmoinesian interval in the Ardmore Basin in southern Oklahoma contains progradational sequences separated by transgressive deposits. Based on the abrupt introduction of detrital chert, a change in paleocurrent directions, and the facies patterns, we suggest that this interval was directly influenced by tectonic activity in the Ouachita fold and thrust belt. Development of a relative sea level curve for this interval based on a genetic stratigraphic sequence approach and biostratigraphic calibration of the curve will allow a comparison with a eustatic curve from the Midcontinent based on fusulinids, and will refine and test this correlation based on studies of conodonts and other fossil groups where present. We have a good stratigraphic framework for most of the interval based on outcrop studies. Additional sedimentologic and stratigraphic studies of both outcrops and subsurface sections will be integrated to develop the genetic stratigraphic sequences.