中朝地台奥陶系层序地层序列及其对比

ORDOVICIAN SEQUENCE SUCCESSIONS ON SINO_KOREA PLATFORM AND THEIR CORRELATION

中朝地台的奥陶系可划分为 1 6个层序 ,4个层序组和 2个中层序 .大部分层序有良好的牙形石带控制 ,可进行跨越板块的广泛对比 .奥陶纪该区有 4次重要的海侵事件 ,分别出现在冶里组下部、北庵庄组下部、峰峰组下部和桃曲坡组下部 ,是全球海平面变化与区域性构造运动共同作用的结果 .冶里组下部层序 (OSq1 )的最大海泛面与牙形石Codyloduslindstroe mi的首现层位十分接近 ,可作为寒武

The Ordovician in the Sino_Korea platform is characterized by shallow_water carbonates of epicontinental sea origin, and can be divided into sixteen 3rd_order sequences, most of which are delineated by subaerial erosion surfaces at their bottoms. These sequences can in turn be grouped as four sequence sets and two meso_sequences. Excellent control of the conodont zones can be observed in the majority of these sequences. In this case, the widespread correlation can be made feasible across the continent and between plates, thus providing an important reference for the Ordovician sequence successions in China. During the Ordovician, the Sino_Korea platform experienced four major transgressions, which occurred in the lower parts of Yeli Formation, Beianzhuang Formation, Fengfeng Formation and Taoqupo Formation respectively, resulting from the joint force of the eustacy and regional tectonism. The mfs of sequence OSq1 in the lower part of the Yeli Formation, very close to the FAD of Codylodus lindstroemi , may be taken as an ideal natural boundary between the Cambrian and Ordovician.