Facies character and geochemical signature in the late Quaternary meteoric diagenetic carbonate succession at the Xisha Islands,South China Sea  

作　　者：Wanli Chen Xiaoxia Huang Shiguo Wu Gang Liu Haotian Wei Jiaqing Wu 

机构地区：[1]Laboratory of Marine Geophysics and Georesources,Institute of Deep-sea Science and Engineering,Sanya 572000,China [2]Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266034,China [3]University of China Academy of Sciences,Beijing 100049,China [4]Institute of Earth and Environmental Science,University of Potsdam,Potsdam 14476,Germany [5]Institute of Marine Geology Survey,Bureau of Hainan Marine Geology Survey,Haikou 570206,China [6]Key Laboratory of Marine Geological Resources and Environment of Hainan Province,Marine Geological Survey Institute of Hainan Province,Haikou 570206,China [7]College of Marine Geosciences,Ocean University of China,Qingdao 266100,China

出　　处：《Acta Oceanologica Sinica》2021年第3期94-111,共18页海洋学报（英文版）

基　　金：The National Natural Science Foundation of China-Guangdong Joint Foundation under contract No.U1701245;the Hainan Provincial Natural Science Foundation of China under contract No.418QN306;the Land and Georesource Bureau of Hainan Province under contract No.SQ2016KJHZ0027;the Pioneer Hundred Talents Program under contract No.Y910091001;the Guangzhou Marine Geological Survey Project under contract No.GZH201400210.

摘　　要：The late Quaternary shallow-water carbonates have been altered by a variety of diagenetic processes,and further influenced by high-amplitude global and regional sea level changes.This study utilizes a new borehole drilled on the Yongxing Island,Xisha Islands to investigate meteoric diagenetic alteration in the late Quaternary shallowwater carbonates.Petrographic,mineralogical,stable isotopic and elemental data provide new insights into the meteoric diagenetic processes of the reef limestone.The results show the variation in the distribution of aragonite,high-Mg calcite(HMC)and low-Mg calcite(LMC)divides the shallow-water carbonates in Core SSZK1 into three intervals,which are UnitⅠ(31.20-55.92 m,LMC),UnitⅡ(18.39-31.20 m,aragonite and LMC)and UnitⅢ(upper 18.39 m of core,aragonite,LMC and HMC).Various degrees of meteoric diagenesis exist in the identified three units.The lowermost UnitⅠhas suffered almost complete freshwater diagenesis,whereas the overlying UnitsⅡandⅢhave undergone incompletely meteoric diagenesis.The amount of time that limestone has been in the freshwater diagenetic environment has the largest impact on the degree of meteoric diagenesis.Approximately four intact facies/water depth cycles are recognized.The cumulative depletion of elements such as strontium(Sr),sodium(Na)and sulphur(S)caused by duplicated meteoric diagenesis in the older reef sequences are distinguished from the younger reef sequences.This study provides a new record of meteoric diagenesis,which is well reflected by whole-rock mineralogy and geochemistry.

关 键 词：shallow-water carbonates meteoric diagenesis elemental concentration facies cycles Xisha Islands late Quaternary 

分 类 号：P736[天文地球—海洋地质]