A heavy mineral viewpoint on sediment provenance and environment in the Qiongdongnan Basin
A heavy mineral viewpoint on sediment provenance and environment in the Qiongdongnan Basin
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DOI：
10.1007/s13131-015-0648-1
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发表时间：
2015-04-01
影响因子：
1.4
通讯作者：
Xiu Chun
中科院分区：
文献类型：
--
作者：
Liu Xiaofeng;Zhang Daojun;Xiu Chun
以11口钻孔岩心重矿物资料为基础，辅以古生物、元素地球化学和地震资料，分析了琼东南盆地沉积物源和环境演化。结果表明，QDNB的基底主要由陆源沉积组成。渐新世以来，青藏高原大体经历了陆海过渡到滨海、浅海、半深海沉积环境的海侵和演化过程。水深呈逐渐增加的趋势，同一时期南部地区普遍大于北部地区。随着沉积环境的变化，牙城组至莺歌海组地层的物源呈现出由本源、短源到远源逐步演化的多物源特征。渐新世早期，沉积物主要为近玄武岩火山碎屑源区和邻近的陆源碎屑源区，此后逐渐形成北至海南岛、南至永乐隆起、东北至神狐隆起、西北部红河水系和西南中南半岛以至更大范围的陆源碎屑源。海南岛物源在渐新世早期开始发育，中中新世以来成为青藏高原主要物源。永乐隆起和神狐隆起的物源区大多发育于渐新世晚期至中新世早期，并在中新世中期逐渐消退。晚中新世，作为中央峡谷沉积物的主要来源，红河系物源大量加入QDNB，其影响在上新世末期终止。莺歌海盆地西部物源起源于中南半岛，发育于上新世至更新世。此外，海洋自生源对盆地(特别是南部地区)的物质贡献也不容忽视。
Based on heavy mineral data in core samples from eleven drillings, supplemented by paleontological, element geochemical and seismic data, the evolution of sediment provenance and environment in the Qiongdongnan Basin (QDNB) was analysed. The results show that the basement in the QDNB was predominantly composed of terrigenous sediments. Since the Oligocene the QDNB has gradually undergone transgressions and evolution processes in sedimentary environment from terrestrial-marine transitional to littoral-neritic, neritic, and bathyal roughly. The water depth showed a gradually increasing trend and was generally greater in the southern region than that in the northern region in the same time. With changes in sedimentary environment, provenances of the strata (from the Yacheng Formation to the Yinggehai Formation) showed principal characteristics of multi-sources, evolving from autochthonous source, short source to distant source step by step. During the Early Oligocene, the sediments were mainly proximal basaltic pyroclastic source and adjacent terrigenous clastic source, afterwards were becoming distant terrigenous clastic sources, including Hainan Island on the north, Yongle Uplift on the south, Shenhu Uplift on the northeast, the Red River System on the northwest and Indochina Peninsula on the southwest, or even a wider region. The Hainan Island provenance began to develop during the Early Oligocene and has become a main provenance in the QDNB since the Middle Miocene. The provenances from Yongle Uplift and Shenhu Uplift most developed from the Late Oligocene to the Early Miocene and gradually subsided during the Middle Miocene. During the Late Miocene, as a main source of sediments filled in the central canyon, the Red River System provenance added to the QDNB massively, whose impact terminated at the end of the Pliocene. The western Yinggehai Basin (YGHB) provenance derived from Indochina Peninsula had developed from the Pliocene on to the Pleistocene. In addition, the material contribution of marine authigenous source to the basin (especially to the southern region) could not be ignored.