琼东南盆地上新世中央峡谷物源分析及其意义

Provenance Analysis of the Pliocene Central Canyon in Qiongdongnan Basin and Its Implications

中央峡谷是南海西北部重要的沉积体之一,物源问题一直是其研究的焦点问题,并且至今没有统一的认识。为了解决中央峡谷物源问题,本文利用重矿物、稀土元素以及锆石年龄等物源分析方法,通过与潜在物源区进行对比,确定了中央峡谷的主要物源,探讨了其成因意义。研究结果表明:1红河是中央峡谷的主要物源,对中央峡谷的形成起到主导作用;2红河水系在历史时期曾经发生重大改变,这种改变可能发生在3.6 Ma至今的某个时期;3中央峡谷源于红河,其形成与大河注入相关,并在琼东南盆地中央凹陷带形成大型储集体,为其成为深水油气勘探目标提供了物质基础。

The Central Canyon is one of the most important sedimentary body in the northwestern part of South China Sea. The provenance problem has always been the focus of the research, and has no uniform understanding. In order to solve the problem, the heavy minerals, rare earth elements and zircon age are used to analyze provenance, by compa- ring with the sediment of potential provenance and discusses the significance of the research. The results show that： （1） the Red River is the main provenance to the Central Canyon and take the leading role in the formation of the Cen- tral Canyon ; （2） The Red River drainage had been changed significantly in the history of its evolution. Such changes may occurs in a period of 3.6 Ma to now; （3） The Central Canyon derived from the red river, and formed large reser- voirs in the central sag belt of Qiongdongnan Basin. It laid the material foundation for the oil and gas exploration target in deep water.