西沙碳酸盐岩建隆发育模式及其主控因素  

EVOLUTIONARY MODEL AND CONTROL FACTORS OF XISHA CARBONATE BUILDUP

作　　者：马玉波[1] 吴时国[2] 杜晓慧[3] 鲁银涛 谷明峰 赵撼霆[2] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]中国科学院海洋研究所中国科学院海洋地质与环境重点实验室,青岛266071 [3]中国地质图书馆,北京100083 [4]中国石油杭州地质研究院,杭州310023

出　　处：《海洋地质与第四纪地质》2011年第4期59-67,共9页Marine Geology & Quaternary Geology

基　　金：国家重点基础研究发展规划项目(2009CB219406);国家自然科学基金重点项目(40930845);中国地质调查局地质调查工作项目(1212010012006)

摘　　要：西沙碳酸盐岩建隆自晚渐新世开始发育于西沙隆起之上,层序分析对比和西沙群岛浅部钻井沉积相的研究表明,西沙碳酸盐岩建隆可分为灰沙岛相、礁坪相、粘结灰岩相、礁格架相和礁后泻湖相等沉积相带。西沙碳酸盐岩建隆在地震剖面上表现为具有一定规模的正地形,顶部强振幅,底界不明显,内部为弱振幅杂乱发射,规模较大的建隆表现为平顶,顶部为强振幅连续反射,内部为弱振幅反射,连续性不一,底界不明显。结合相对海平面变化影响分析,建立了西沙碳酸盐岩建隆的沉积模式,相对海平面的上升引起碳酸盐岩建隆向构造高部位的迁移,以及建隆内部水体的流通,而相对海平面的下降则引起建隆的向海侧积以及其顶部水体的流通性降低和泻湖的形成。此外,构造作用、陆源碎屑输入及水体温度盐度等因素也影响着西沙碳酸盐岩建隆的发育。Carbonate buildups started growing up in the Late Oligocene on the edge of the Xisha Islands and structural highs.Sequence analysis and drilling well facies analysis suggest that a carbonate buildup may consist of various facies,such as the lime sand island facies,reef flat facies,bindstone facies,reef framework facies and backreef lagoon facies etc.In seismic profiles,the carbonate platform usually occurs as a positive landform with high amplitude at the top,low amplitude and chaotic reflection inside,and an ambiguous boundary at the bottom.Large scale carbonate buildups usually have high amplitude,continuous reflection and a flat top.We proposed in this study a sedimentary model for the Xisha carbonate buildup with respect to relative sea level changes.The rise of relative sea level leads to the retreat of carbonate buildup toward the structure highs,while dropping of the relative sea level causes the lateral accretion of the carbonate buildup towards the sea,leaving a lagoon behind the buildup.Besides,tectonic movement,terrigenous clastic input and temperature and salinity of sea water also influence the development of the carbonate buildup.

关 键 词：碳酸盐岩建隆 沉积模式 主控因素 相对海平面 西沙群岛 

分 类 号：P736.2[天文地球—海洋地质]