古地理学报 ›› 2020, Vol. 22 ›› Issue (6): 1197-1208. doi: 10.7605/gdlxb.2020.06.082

• 地球化学与沉积环境 • 上一篇    下一篇

中国南海西沙碳酸盐岩台地形成过程及控制因素:来自西科1井的地球化学证据

鲁毅1, 崔宇驰1, 刘新宇2, 邵磊1, 乔培军1   

  1. 1. 同济大学海洋地质国家重点实验室,上海 200092;
    2. 中海油海南能源有限公司,广东湛江 524057
  • 收稿日期:2019-10-08 修回日期:2020-03-09 出版日期:2020-12-01 发布日期:2020-12-03
  • 通讯作者: 邵磊,男,1960年生,同济大学海洋与地球科学学院教授,主要从事沉积岩石学和沉积地球化学研究。E-mail: lshao@tongji.edu.cn。
  • 作者简介:鲁毅,男,1996年生,同济大学海洋与地球科学学院硕士研究生,海洋地质专业,主要从事沉积岩石学及沉积地球化学研究。E-mail: luyi962180@tongji.edu.cn。
  • 基金资助:
    国家自然科学基金项目(编号: 41576059)以及国家科技重大专项(编号: 2017ZX05026005-005)联合资助;

Sedimentary types and features of gravity flow depositional systems from Late Oligocene to Early Miocene in Liwan sag, Pearl River Mouth Basin

Lu Yi1, Cui Yu-Chi1, Liu Xin-Yu2, Shao Lei1, Qiao Pei-Jun1   

  1. 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai200092, China;
    2. China National Offshore Oil CorporationHainan Energy Co. Ltd., Guangdong Zhanjiang524057, China
  • Received:2019-10-08 Revised:2020-03-09 Online:2020-12-01 Published:2020-12-03
  • Contact: Shao Lei,born in 1960,is a professor of Tongji University. He is mainly engaged in sedimentary petrology and sedimentary geochemistry. E-mail: lshao@tongji.edu.cn.
  • About author:Lu Yi,born in 1996,is a master degree candidate of Tongji University.Now he is mainly engaged in researches on sedimentary petrology and sedimentary geochemistry.E-mail: luyi962180@tongji.edu.cn.
  • Supported by:
    Co-funded by the National Natural Science Foundation of China(No.41576059),and the National Science and Technology Major Project of China(No.2017ZX05026005-005)

摘要: 通过对南海西沙石岛已完钻的科学探井——西科1井进行岩性组合特征、元素地球化学、TEX86等多种指标分析,尝试恢复了西沙地区中新世以来海平面变化,讨论了碳酸盐岩台地形成发育的控制因素。发现受控于南海区域性构造事件及全球海平面变化的双重影响,西沙地区海平面呈现早中新世高—中中新世低—晚中新世到上新世高—第四纪低的变化趋势,海水温度从早中新世到上新世呈整体下降趋势。岩性组合特征揭示,西沙地区碳酸盐岩台地在早中新世开始发育,到中中新世逐渐繁盛,在中中新世末达到顶峰,形成了包含潟湖相在内的大型礁盘;在晚中新世—上新世由于海平面快速上升以及海水温度下降而逐渐衰退淹没,到第四纪进一步持续萎缩。研究发现,西沙地区在早中新世和晚中新世—上新世,出现2次较强的白云岩化作用,与海平面下降造成碳酸盐岩台地暴露剥蚀直接相关。西科1井揭示的碳酸盐岩台地的发育演化过程是南海新生代碳酸盐岩台地繁荣与消亡的代表,是南海新生代构造演化与全球气候变迁相互作用的综合结果。

关键词: 南海, 西科1井, 碳酸盐岩台地, 地球化学, 分子化合物

Abstract: Based on combination features of lithology,element geochemistry,TEX86 and many other indicators of Well Xike-1,Shidao Island,Xisha area,South China Sea,we aim to reconstruct the regional sea-level changes in Xisha area since the Early Miocene,and discuss the dominant factors of the carbonate platforms formation and development. Under the impacts of both the regional tectonic events in the South China Sea and the global sea level changes,it is found that the sea level in Xisha area shows a high-low-high-low variation trend during the Early Miocene,Middle Miocene,Late Miocene and Pliocene,and Quaternary. The sea surface temperature shows an overall downward trend from the Early Miocene to Pliocene. The combination features of lithology indicate that the Xisha carbonate platform initially formed in the Early Miocene,and it gradually flourished and developed in the Middle Miocene,then reached up to the peak in the Middle Miocene characterized as the formation of large reefs with lagoon facies. During the Late Miocene-Pliocene,the rapid increase of sea level and water temperature decrease led to the gradual shrinking and submergence of the carbonate platform which further shrinked in the Quaternary.It is found that two intense dolomitization events occurred in Xisha area during the Early Miocene and Late Miocene-Pliocene,respectively. These events are closely related to the exposure and erosion of carbonate platforms caused by regional sea-level drop. The carbonate platform evolution of Xike-1 is there presentation of the prosperity and extinction of the Cenozoic carbonate platform in the South China Sea. It was the comprehensive result of the Cenozoic tectonic evolution and global climate changes in the South China Sea.

Key words: South China Sea, Well Xike-1, carbonate platform, geochemistry, molecular compound

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