南海北部深水区LS33a钻井微体古生物年代地层格架

Chronostratigraphic Framework based on Micro-paleontological Data from Drilling LS33a in Deep Water Area of Northern South China Sea

南海北部琼东南盆地深水区接收了渐新世以来数千米厚的海相沉积地层,蕴藏着丰富的微体古生物化石。对深水区LS33a钻井岩芯的取样和化石鉴定,识别出21个浮游有孔虫化石带(N22带~P19带)和12个钙质超微化石带(NN19带~NP24带)。通过与大洋钻探(ODP)在南海实施的184航次的钻探结果和"国际年代地层表(2012)"等的对比分析,探讨了化石事件的地质年代意义,构建了LS33a钻井生物年代地层格架。在此基础上,讨论了更新统与上新统、上上新统与下上新统、上新统与中新统、上中新统与中中新统、中中新统与下中新统、中新统与渐新统、上渐新统与下渐新统之间地层界线位置以及崖城组、陵水组、三亚组、梅山组、黄流组、莺歌海组和乐东组地层的时代归属,建立了适用于南海北部深水区的高分辨率综合年代地层格架。

Since the Oligocene,thousands of meters of marine strata have been deposited in the deep water area of the Qiongdongnan Basin in the northern South China Sea,in which micro-fossils are enriched.Twenty-one planktonic foraminiferal fossil zones(N22 zone-P19 zone)and twelve calcareous nannofossil zones(NN19 zone-NP24 zone)were recognized by fossil identification of the cored samples from drilling LS33a in deep water area.Combined with previous results of the ODP184 Leg implemented in the South China Sea and the Geologic Time Scale 2012,the geological ages of the fossil events were discussed,and the chronostratigraphic framework based on micro-paleontological data from drilling LS33a was constructed.On this basis,this paper discusses the position of the stratigraphic boundary between the Pleistocene and the Pliocene,the Upper Pliocene and the Lower Pliocene,the Pliocene and the Miocene,the Upper Miocene and the Middle Miocene,the Middle Miocene and the Lower Miocene,the Miocene and the Oligocene,the Upper Oligocene and the Lower Oligocene,defines the age assignment of Yacheng Formation,Lingshui Formation,Sanya Formation,Meishan Formation,Huangliu Formation,Yinggehai Formation and Ledong Formation,and finally establishes a high-resolution comprehensive chronostratigraphic framework suitable for the deep water area of the northern South China Sea.