摘要
本文基于琼东南盆地15口钻井和西沙石岛岛礁"西科一井"的钻井资料,结合过井地震剖面,系统分析了琼东南盆地沉降(沉积充填)和西沙岛礁生长速率及其变化特征,探讨了青藏高原隆升与琼东南盆地沉降和西沙岛礁发育之间的耦合关系,三者在发育时间和发育过程上表现出高度的一致性,且南海古海水中Sr同位素组成变化也表现出对青藏高原隆升速率变化很好的响应。相对于深水区,浅水区的沉积物堆积速率及其变化能够更好地反映盆地的沉降速率及其变化。琼东南盆地的沉降(沉积物堆积)和西沙岛礁的发育过程均可以分为3个阶段,分别对应于青藏高原的3个隆升期,时间自老到新分别为:23~16Ma BP、16~5.5 Ma BP、5.5 Ma BP至今。相比而言,岛礁的发育过程与青藏高原的隆升之间的耦合关系更为密切。在青藏高原的快速隆升期,相应发生盆地沉降(沉积充填或沉积物堆积)和岛礁生长速率的加快,同时对应发生了南海海水87Sr/86Sr比值的增大,说明青藏高原隆升可能是影响琼东南盆地乃至整个南海沉降(沉积充填)、岛礁发育和古海水Sr同位素组成变化的主要因素。
Based on the drilling data of the 15 wells in the Qiongdongnan Basin and＂Xike-1＂well in the Shi Island of Xisha Islands,combining with the seismic section through those wells,this passage systematically analyzed the subsiding（sediments filling）rates of Qiongdongnan Basin,the developing rates of the Xisha Islands＇ reefs and their variation features.Additionally,the coupling relationships among the Qinghai-Tibet Plateau uplifting,the Qiongdongnan Basin subsiding and the Xisha Islands＇ reefs developing were also discussed.The former three exhibit a high degree of consistency in development time and process.The ancient seawater Sr isotopic composition of the South China Sea composition provides an important evidence for this consistency.The changes of the sediment accumulation rates in the shallow water can better reflect the changes of the basin subsiding rates in comparison to the deep water.The processes of Qiongdongnan Basin subsiding（sediments accumulation）and Xisha Islands＇ reefs developing can both be divided into three stages,corresponding to the three phases of the Qinghai-Tibet Plateau uplifting,they are：23-16 Ma BP,16-5.5 Ma BP,5.5 Ma BP-today respectively in chronological order.In comparison,the coupling relationship between the reefs developing process and Qinghai-Tibet Plateau uplifting is more closely.In the rapid uplifting stage of the Qinghai-Tibet Plateau,the basin sedimentary filling（sediments accumulation）rates and the reefs growth rates accelerated correspondingly,and 87Sr/86 Sr ratios of the South China Sea increased.It indicates that the Qinghai-Tibet Plateau uplifting is the main factor that impacted the basin subsidence（sedimentary fill）,reefs development and ancient seawater Sr isotopic composition in the Qiongdongnan Basin even the entire South China Sea.
出处
《海洋学报》
CAS
CSCD
北大核心
2017年第1期52-63,共12页
基金
国家科技重大专项课题(2011ZX05025-002-03)
中海石油(中国)有限公司专项课题(CCL2013ZJFNO729)
关键词
青藏高原隆升
琼东南盆地沉降
西沙岛礁发育
耦合关系
Qinghai-Tibet Plateau uplifting
Qiongdongnan Basin subsiding
Xisha Islands＇ reefs developing
coupling relationships
