This is a new report on the early Eocene radiolarian fauna from the Sangdanlin section in the Gyirong region, along the southern margin of the Yarlung Zangbo Suture Zone. The Sangdanlin section measured in this study ...
详细信息
This is a new report on the early Eocene radiolarian fauna from the Sangdanlin section in the Gyirong region, along the southern margin of the Yarlung Zangbo Suture Zone. The Sangdanlin section measured in this study is divided into three lithostratigraphic units from bottom to top: the Zongzhuo, Sangdanlin, and Zheya formations. Abundant radiolarian fossils were obtained from the Sangdanlin section and 54 species of 30 genera were identified and assigned as follows: Cryptamphorella conara-C. macropora the late Cretaceous Zone and Amphisphaera coronate, Buryella tetradica-Bekoma campechensis, and ***-B. divaricata the Paleocene-early Eocene Interval Zones. The Paleocene– early Eocene radiolarian zones compare to the radiolarian zones RP4-RP8 in New Zealand. Based on the data of radiolaria and lithofacies, it is suggested that the Zongzhuo Formation should be deposited along the base of the north-facing, continental slope of the Greater Indian continental margin, and the Sangdanlin Formation should be a deep marine, sedimentary sequence located in a foreland basin. The early Eocene radiolarian fauna in the Sangdanlin Formation constrains the initial age of the India-Asia collision to no later than 53.6 Ma.
疑源类是一类有机质壁保存的微体化石,大多数疑源类是海洋真核微体浮游植物的休眠孢囊。作为初级生产者,浮游植物不仅能为海洋生态系统中高营养级成员提供食物,而且深刻影响着全球碳氧循环。奥陶纪以来,华南板块疑源类的多样性迅速增高,在早中奥陶世之交达到多样性顶峰(Li et al.,2007)。因此,详细探究疑源类在奥陶纪早期的演化对揭示奥陶纪生物大辐射的启动机制有重大意义。湖北宜昌兴山古洞口剖面位于华南板块扬子台地,下奥陶统地层出露完整,包括南津关组、分乡
暂无评论