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

本研究的目的是通过对比盆地内受隆升直接影响的旋回模式和时间与起伏旋回的模式和时间，来约束沉降和构造在宾夕法尼亚旋回起源中的相对作用。俄克拉何马州南部Ardmore盆地的德摩因期段包含由海侵沉积分隔的进积层序。根据碎屑燧石岩的突入、古流方向的变化和相模式，认为该层序直接受到瓦希托褶皱和冲断带构造活动的影响。基于成因地层序列方法和生物地层校准曲线的相对海平面曲线的发展将允许与来自中大陆的基于fusulinids的上升曲线进行比较，并将根据对牙形刺和其他化石群的研究来完善和测试这种相关性。在露头研究的基础上，我们对大部分层段有了良好的地层格架。将结合对露头剖面和地下剖面的其他沉积学和地层学研究来发展成因地层序列。

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.