琼州海峡西口早—中全新世海滩岩的岩石学特征及古海平面重建意义  

Early-Middle Holocene beach rocks at the western Qiongzhou Strait and their significance for paleo-sea level reconstruction

作　　者：许国强 梁定勇 贾丽云[3] 肖瑶 文玲 王明珠 李孙雄 陈波 符彩花 杜鹃 马波[6] 高芳蕾[6] 陈婕 林亚分 邢忠 林义华[6] XU Guoqiang;LIANG Dingyong;JIA Liyun;XIAO Yao;WEN Ling;WANG Mingzhu;LI Sunxiong;CHEN Bo;FU Caihua;DU Juan;MA Bo;GAO Fanglei;CHEN Jie;LIN Yafen;XING Zhong;LIN Yihua(The Key Laboratory of Marine Geological Resources and Environment of Hainan Province,Haikou,Hainan 570206,China;Comprehensive Institute of Geological Investigation of Hainan Province,Haikou,Hainan 570206,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;School of Earth and Environmental Sciences,the University of Queensland,QLD,61-7-4072,Australia;Marine of Geological Survey of Hainan Province,Haikou,Hainan 570206,China;Hainan Geological Survey,Haikou,Hainan 570206,China)

机构地区：[1]海南省海洋地质资源与环境重点实验室,海南海口570206 [2]海南省地质综合勘察院,海南海口570206 [3]中国地质科学院地质力学研究所,北京100081 [4]昆士兰大学,澳大利亚布里斯班,澳大利亚61-7-4072 [5]海南省海洋地质调查研究院,海南海口570206 [6]海南省地质调查院,海南海口570206

出　　处：《地质学报》2023年第7期2386-2398,共13页Acta Geologica Sinica

基　　金：海南省海洋地质资源与环境重点实验室自主课题(编号ZZ[2020]2019256-02);2019年海南省基础与应用基础研究计划(自然科学领域)高层次人才项目基金(编号2019RC348,2019RC346);中国地质科学院地质力学研究所基本科研业务费(编号DZLXJK20221)联合资助的成果。

摘　　要：笔者在琼州海峡西口第四系松散沉积物中新发现碳酸盐胶结岩,通过生物碎屑AMS14C同位素定年、全岩X衍射定量分析、扫描电镜、阴极发光、全岩主微量元素地球化学测试等方法对其进行了年代学和成因研究。结果显示,碳酸盐胶结岩的成岩时代为早—中全新世,具有等厚纤柱状环边胶结、重力悬挂胶结、马牙状胶结、(似)共轴增生胶结、非等轴胶结等5种胶结物特征;阴极发光环带具有广泛发育、环带密集,可见淡水和海水相互作用的咸淡水混合带,说明其成岩环境包括淡水渗流带、咸淡水混合带、海水渗流带、海水潜流带;结合其沉积主微量元素特征,其赋存层位的沉积环境为海岸沉积环境,滨岸沉积相障壁岛亚相,属于海滩岩。综合雷州半岛西南部灯楼角珊瑚礁的海平面记录,重建了全新世琼州海峡西口地区海平面演化历史:9.9~6.7 ka BP海侵期、6.7~6.2 ka BP海退期、6.2~4.2 ka BP海侵期和4.2 ka BP至今的稳定期等四个阶段。Carbonate cements were discovered in the Quaternary sediments at the western Qiongzhou Strait.By means of the bioclastic AMS14C isotope dating,whole-rock X-ray diffraction quantitative analysis,scanning electron microscopy,cathodoluminescence study,and whole-rock major and trace elements geochemical testing,the geochronology and genesis of rocks were studied.Results show that the diagenetic age of the carbonate cements is early to Middle Holocene,and the cements are characterized by five kinds such as isopachous fiber columnar rim cements,gravity suspension cements,horse-tooth cements,(quasi-)coaxial accretion cements,and non-isopachous cements.The cathodoluminescence zone is widely developed and dense,and the brackish fresh water mixed zone with interaction between fresh water and sea water can be seen,indicating that the diagenetic environment includes fresh water percolation zone,brackish fresh water mixed zone,sea water percolation zone,and sea water undercurrent zone.Combined with the characteristics of the main and trace elements analyses,the carbonate cements formed in the coastal sedimentary environment,and the coastal sedimentary facies is barrier island subfacies,which belongs to beach rock.The sea level evolution history of the western Qiongzhou Strait area in the Holocene is reconstructed by combining these results with the sea level records of the Dengloujiao coral reef in the southwest of Leizhou Peninsula.There were four stages:9.9~6.7 ka BP transgression stage,6.7~6.2 ka BP regression stage,6.2~4.2 ka BP transgression stage and 4.2 ka BP stable stage.

关 键 词：琼州海峡西口 古海滩岩 全新世 海平面重建 

分 类 号：P534.632[天文地球—第四纪地质学] P58[天文地球—古生物学与地层学] P597.3[天文地球—地质学]