| LIU Xiaofeng,ZHANG Daojun,ZHAI Shikui,LIU Xinyu,CHEN Hongyan,LUO Wei,LI Na,XIU Chun. 2015. A heavy mineral viewpoint on sediment provenance and environment in the Qiongdongnan Basin. Acta Oceanologica Sinica, 34(4):41－55 |
| A heavy mineral viewpoint on sediment provenance and environment in the Qiongdongnan Basin |
| 琼东南盆地物源和沉积环境变化的重矿物证据 |
| Received:June 23, 2014 Revised:December 02, 2014 |
| DOI：10.1007/s13131-015-0648-1 |
| Key words:heavy minerals provenance sedimentary environment Qiongdongnan Basin northern South China Sea |
| 中文关键词: 重矿物 物源 沉积环境 琼东南盆地 南海北部 |
| 基金项目: |
| Author Name | Affiliation | E-mail | | LIU Xiaofeng | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | | | ZHANG Daojun | Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China | | | ZHAI Shikui | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | zhaishk@public.qd.sd.cn | | LIU Xinyu | Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China | | | CHEN Hongyan | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | | | LUO Wei | Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China | | | LI Na | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | | | XIU Chun | Key Laboratory of Submarine Geosciences and Prospecting Techniques of Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China | |
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| Abstract: |
| 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 multisources, 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. |
| 中文摘要: |
| 基于11口钻井岩心样品的重矿物数据,结合古生物学、元素地球化学和地震资料,对琼东南盆地的物源及沉积环境演变进行了分析.结果表明,盆地基底沉积以陆相沉积为主,自渐新世起,盆地逐渐接受海侵,大致经历了海陆过渡→滨浅海→浅海→半深海的沉积环境演变过程,水深总体呈逐渐增大的趋势且在同一时期南部区域水深整体上大于北部.随着沉积环境的变化,各地层(崖城组至莺歌海组)物源呈现出多源性特征,经历了原地→近源→远源的演变过程.在渐新世早期,物源以近源玄武质火山碎屑和邻区陆源碎屑为主,之后演变为远源的陆壳碎屑,物源区包括北部海南岛、南部永乐隆起、东北部神狐隆起、西部红河、西南部中南半岛乃至更广的区域.海南岛物源自早渐新世便开始发育,至中中新世成为盆地最主要的物源,并持续至现今;永乐隆起和神狐隆起物源在晚渐新世至早中新世期间最为发育,于中中新世逐渐消退;红河物源于晚中新世大规模加入,为中央峡谷的主要沉积物源,影响至上新世结束;中南半岛莺西物源自上新世发育,影响至更新世时期.此外,自生组分对盆地(尤其是南部区域)的沉积贡献也不容忽视. |
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