刘刚, 何其江, 李亮, 吴时国, 韩孝辉, 王雪木, 蔡观强, 王大伟. 西沙群岛永乐环礁瀉湖沉积速率及地球化学特征[J]. 海洋地质与第四纪地质, 2018, 38(6): 69-77. DOI: 10.16562/j.cnki.0256-1492.2018.06.007
引用本文: 刘刚, 何其江, 李亮, 吴时国, 韩孝辉, 王雪木, 蔡观强, 王大伟. 西沙群岛永乐环礁瀉湖沉积速率及地球化学特征[J]. 海洋地质与第四纪地质, 2018, 38(6): 69-77. DOI: 10.16562/j.cnki.0256-1492.2018.06.007
LIU Gang, HE Qijiang, LI Liang, WU Shiguo, HAN Xiaohui, WANG Xuemu, CAI Guanqiang, WANG Dawei. Sedimentation rate and geochemical characters of the lagoonal deposits in the Yongle Atoll, Xisha Islands[J]. Marine Geology & Quaternary Geology, 2018, 38(6): 69-77. DOI: 10.16562/j.cnki.0256-1492.2018.06.007
Citation: LIU Gang, HE Qijiang, LI Liang, WU Shiguo, HAN Xiaohui, WANG Xuemu, CAI Guanqiang, WANG Dawei. Sedimentation rate and geochemical characters of the lagoonal deposits in the Yongle Atoll, Xisha Islands[J]. Marine Geology & Quaternary Geology, 2018, 38(6): 69-77. DOI: 10.16562/j.cnki.0256-1492.2018.06.007

西沙群岛永乐环礁瀉湖沉积速率及地球化学特征

Sedimentation rate and geochemical characters of the lagoonal deposits in the Yongle Atoll, Xisha Islands

  • 摘要: 西沙群岛环礁海底沉积物的沉积速率及其地球化学特征是环礁沉积地貌环境演化研究的重要指标。为了探讨永乐环礁晚全新世以来沉积速率的变化和常量化学元素垂向分布与变化特征,我们在西沙群岛永乐环礁瀉湖内进行了详细的取样,开展了重力柱状样的AMS14C同位素测年和沉积物地球化学分析。永乐环礁晚全新世海底沉积物沉积速率约0.778mm/a;根据沉积物常量地球化学含量测试,CaO含量最高,其次是MgO,其他元素含量均小于1%,可以将常量元素组分分为5类。CaCO3含量和MgO/Al2O3含量比值都非常高,说明本区沉积物的来源主要为生物成因,极少量来自其他物质输入;与晚全新世气候相比,总体上永乐环礁瀉湖沉积速率随SST增加而升高。

     

    Abstract: A gravity core, labeled as Core YLD01, was collected from the lagoon of the Yongle Atoll. AMS14C isotopic dating and geochemical analysis were carried out aiming to reveal the changes in sedimentation rate during Holocene as well as the vertical variation in major chemical elements with time. The AMS14C isotope dating suggests that the sedimentation rate in the lagoon of Yongle Atoll is about 0.778mm/a since the Holocene. Geochemical composition of the sediments indicated that CaO dominates the lagoonal deposits followed by MgO, and the others are all lower than 1 %. The major elements can be grouped into five categories. Both the CaCO3 content and the ratio of MgO/Al2O3 are very high, indicating that the major source of sediments is from native organisms. Other source of materials from outside is very little. Compared the data with Late Holocene climatic change, the sedimentation rate of the lagoonal deposits was obviously increased with the rise of SST on the Yongle Atoll.

     

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