华南上扬子区奥陶纪特马豆克阶的海平面变化

在较为精细的生物地层学研究基础上,对位于华南上扬子区4条剖面的沉积相组合以及沉积相序列进行分析,建立上扬子区特马豆克期高分辨率相对海平面变化曲线。识别出10个沉积相,划分出3个沉积相组合,分别沉积于浅潮下带、深潮下带和页岩盆地带;识别出5次重要的海侵事件,分别发生在TS.1a早期、TS.1a晚期、TS.1c早期、TS.1c晚期和TS.1d晚期,其中TS.1c早期的海侵为特马豆克期最大海侵事件。通过与其他板块海平面变化曲线的对比,发现上扬子区海平面变化主要受全球海平面变化的控制。

Sea-Level Fluctuations in the Tremadocian of the Ordovician in the Upper Yangtze Region of South China

Four Tremadocianian sections of the Upper Yangtze Region of South China are intensively studied for biostratigraphical division and correlation. Based on the analysis of lithofacies, lithofacies associations, and facies successions, the detailed sea level curves of Tremadocian are revealed. Ten lithofacies which are grouped into three lithofacies associations deposited in the shallow subtidal, deep subtidal and shale basin zones. At least five major transgression events are recognized from each section in early TS.1a, late TS.1a, early TS.1c, late TS.1c and late TS.1d. The most major transgression event occurred in early TS.1c. Compared with other paleoplates, eustatic sea level changes might be the major controlling factor for the sea level fluctuations of the Upper Yangtze Region of South China.