二叠-三叠系之交牙形石、火山灰层及生物沉积相序列

在华南不同的古地理分区内选择具有代表性的剖面，进行高分辨率牙的形石带、火山灰层的特征及生物沉积相研究，首先构建起一个多重的地层柱状。通过解析火山灰层与牙形石带的地层关系，建立各相关的事件地层序列，将火山灰的绝对年龄与牙形石带研究相结合，更精细地建立二叠-三叠系之交的牙形石序列，力争为界面附近的生物灭绝事件模型提供一个新思路。此外，试图在牙形石带和火山灰层联合限定的等时地层格架内，配置生物沉积相的时-空组合关系，厘定生物沉积演化相期，恢复全球性生物灭绝与复苏的节律，考察二叠-三叠纪过度期的灾难事件，探索二叠-三叠系之交的生物大灭绝原因。

This study is choosing representative section from diverse paleogeographical setting and carries out studies of high-resolution conodont biozone, ash-bed and biosedimentary facies through Permian-Triassic boundary. As a result multiply columnar section of every geographic setting will be established. Proceed to the next step comparison of conodont biozones between the sections in diverse geographic setting should make up a spatial succession of conodont biozones in Permian-Triassic boundary interval. Dissection of relationships between ash-beds and conodont biozones could calibrate stratigraphical level of ash-beds and make up an event-stratigraphical succession. So that will provide a credible pattern for dating the ages of P-T boundary and extinct events. Farther in order to establish a succession of biosedimentary phase in Permian-Triassic boundary interval and reconstruct pattern of global biotic extinction and recovery. We would like to match space-time relationships in isochronous stratigraphical framework that is cooperatively controlled both by conodont biozones and by ash beds. Finally to understand the cause of great extinction we should carry out study of catastrophic events in Permian-Triassic boundary interval.