李娜, 翟世奎, 刘新宇, 陈奎, 姜秀莉, 修淳, 宗统, 刘晓锋, 陈宏言, 王淑杰, 淳明浩. 琼东南盆地深水区LS33-1-1钻井岩心微量元素地球化学特征及其沉积环境[J]. 海洋地质与第四纪地质, 2014, 34(3): 1-12. DOI: 10.3724/SP.J.1140.2014.03001
引用本文: 李娜, 翟世奎, 刘新宇, 陈奎, 姜秀莉, 修淳, 宗统, 刘晓锋, 陈宏言, 王淑杰, 淳明浩. 琼东南盆地深水区LS33-1-1钻井岩心微量元素地球化学特征及其沉积环境[J]. 海洋地质与第四纪地质, 2014, 34(3): 1-12. DOI: 10.3724/SP.J.1140.2014.03001
LI Na, ZHAI Shikui, LIU Xinyu, CHEN Kui, JIANG Xiuli, XIU Chun, ZONG Tong, LIU Xiaofeng, CHEN Hongyan, WANG Shujie, CHUN Minghao. THE TRACE ELEMENTS GEOCHEMISTRY AND DEPOSITIONAL ENVIRONMENT CHANGES RECORDED IN THE CORE OF WELL LS33-1-1 IN DEEPWATER AREA OF QIONGDONGNAN BASIN[J]. Marine Geology & Quaternary Geology, 2014, 34(3): 1-12. DOI: 10.3724/SP.J.1140.2014.03001
Citation: LI Na, ZHAI Shikui, LIU Xinyu, CHEN Kui, JIANG Xiuli, XIU Chun, ZONG Tong, LIU Xiaofeng, CHEN Hongyan, WANG Shujie, CHUN Minghao. THE TRACE ELEMENTS GEOCHEMISTRY AND DEPOSITIONAL ENVIRONMENT CHANGES RECORDED IN THE CORE OF WELL LS33-1-1 IN DEEPWATER AREA OF QIONGDONGNAN BASIN[J]. Marine Geology & Quaternary Geology, 2014, 34(3): 1-12. DOI: 10.3724/SP.J.1140.2014.03001

琼东南盆地深水区LS33-1-1钻井岩心微量元素地球化学特征及其沉积环境

THE TRACE ELEMENTS GEOCHEMISTRY AND DEPOSITIONAL ENVIRONMENT CHANGES RECORDED IN THE CORE OF WELL LS33-1-1 IN DEEPWATER AREA OF QIONGDONGNAN BASIN

  • 摘要: 为了研究琼东南盆地深水区的沉积环境及物源,对琼东南盆地深水区LS33-1-1钻井岩心样品的微量元素地球化学特征进行了分析,结果表明:研究区自渐新世以来沉积环境多变,物源复杂;在崖三段沉积早期,物源主要为当地或附近的基性玄武质火山碎屑,可能来自南海扩张引起的岩浆喷发活动;自崖三段沉积晚期(早于31.5 Ma)以来,物源以陆源和海洋自生沉积为主,其中火山岩风化产物占有相当的比例。LS33-1-1钻井岩心沉积物的微量元素地球化学特征在距今31.5、28.4、25.5、23、16、8.2、5.5、2.7 Ma均发生明显突变,表明沉积环境及物源均发生了明显的变化,反映了构造运动的影响。各地球化学指标在崖三段底部4 207 m左右的突变,反映了琼东南盆地发生了较大规模的构造运动,造成了沉积物源由以基性火山碎屑为主转变为以陆源碎屑为主。在渐新世-中新世界线(23 MaBP)附近,各项指标均表现出明显的突变,表明在ODP1148站及珠江口盆地深水区发现的物源突变事件(白云运动)也影响到了琼东南盆地深水区。

     

    Abstract: In order to reveal the sedimentary environment and provenance of the deepwater deposits in the Qiongdongnan Basin(QDNB), trace elements geochemistry of the core samples of Well LS33-1-1 in the deepwater area of QDNB is studied in this paper. Since Oligocene, the study area has been suffered severe changes in depositional environment, and the provenance of sediments was complicated. In the early stage of the Third Member of the Yacheng Formation, the sediments were mainly from basaltic pyroclastic rocks, which might be the contribution from magmatic activity resulted from the expansion of the South China Sea. Since the late stage of the Third Member of the Yacheng Formation, however, the sediments were mainly from terrigenous and marine deposits,with a considerable proportion of weathering product of volcanic rocks. The trace elements geochemistry of the study area shows drastic variation at 31.5 MaBP, 28.4 MaBP, 25.5 MaBP, 23 MaBP, 16 MaBP, 8.2 MaBP, 5.5 MaBP, 2.7 MaBP respectively, indicating the significant changes in sedimentary environment and provenance, as the results of the tectonic movement. The change in geochemical indicators at the bottom (about 4 207 m) of the Third Member of the Yacheng Formation suggests a strong tectonic movement in QDNB, leading to the transition of sediment provenance from the basic pyroclastic rocks into the terrigenous deposits. Close to the Oligocene-Miocene boundary (23 MaBP), all indices show significant variation, indicating that the Baiyun Movement, whicvh was discovered in the ODP1148 Station and the Pearl River Mouth Basin, also affected the QDNB deepwater area.

     

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