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

这项研究的目的是通过测试直接受隆升影响的盆地中的旋回模式和时间与海平面旋回的模式和时间的比较，来限制隆升和构造对宾夕法尼亚旋回起源的相对作用。俄克拉荷马州南部Ardmore盆地的Desmoinesian层段包含由海侵沉积隔开的进积层序。根据碎屑硅质岩的突然引入、古流方向的改变和相模式，我们认为该段直接受到瓦奇塔褶皱冲断带构造活动的影响。根据成因地层层序方法和对该曲线的生物地层学校准，为这一段建立相对海平面曲线，这将使我们能够与基于丝虫类的中大陆海平面曲线进行比较，并将根据对牙形刺和其他化石群(如果存在)的研究来完善和测试这种相关性。根据露头研究，我们在大部分时间段都有一个很好的地层格架。此外，还将整合露头和地下剖面的沉积学和地层学研究，以开发成因地层序列。

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.