南沙海区万安盆地中新世碳酸盐台地的地震响应与沉积特征  

Seismic Responses and Sedimentary Characteristics of the Miocene Wan'an Carbonate Platform in the Southern South China Sea

作　　者：吕彩丽[1,2] 姚永坚[3] 吴时国[1] 姚根顺[4] 

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室,山东青岛266071 [2]中国科学院研究生院,北京100049 [3]广州海洋地质调查局,广东广州510760 [4]中国石油天然气集团公司杭州地质研究院,浙江杭州310023

出　　处：《地球科学（中国地质大学学报）》2011年第5期931-938,共8页Earth Science-Journal of China University of Geosciences

基　　金：中国科学院知识创新项目(No.KZCX-YW-Q05-04);国家重点基础性研究(No.2009CB219406)

摘　　要：利用反射地震并结合部分钻井资料,通过对万安盆地大量地震资料的详细解释,对研究区内碳酸盐台地进行地震识别,进而探讨台地的沉积特征与时空分布.万安盆地碳酸盐台地最初发育于早中新世,并于中中新世时达顶盛时期,呈南北向展布,主要分布在盆地中部走滑断块构造高部位及盆地南部边缘.东西两带台地具有不同的构造沉积背景,西带为被断层复杂化的东倾斜坡,离物源较近,为碳酸盐岩与碎屑岩互层沉积;东带濒临南海海盆,离物源较远,碳酸盐岩厚度大、岩性较纯.层序地层分析表明,万安盆地碳酸盐台地主要发育于海侵体系域和高水位体系域.单个台地沉积相在平面上呈圈层结构展布,相带窄但较规则,可能包括:台内相、台缘相、前缘斜坡相(缓坡与陡坡)和盆底相,但只在台地东侧发育盆底相,这与盆地东侧靠近南海海盆的地质环境有关.Based on a large quantity of seismic data interpretation and some drilling data in Wan＇an basin,the Miocene Wan＇an carbonate platforms are identified from seismic reflection profiles and their sedimentary characteristics as well as spatial and temporal distributions are documented in detail.The Wan＇an carbonate platforms developed initially during the Early Miocene and reached its prosperous period during the Middle Miocene,showing north-south orientation,and mainly occurring on the hanging wall of the strike-slip fault block in the centre of the basin and the southern basin margin.The Miocene Wan＇an carbonate platform can be divided into the east band and the west band according to two different sedimentary tectonic forming backgrounds,where the west side is the slope dipping towards the east fractured by faults and approaches land-source areas resulting in alternating clastic and carbonate rocks,while the east side is close to the South China Sea basin and far from terrigenous areas showing thick and pure carbonate rocks.The sequence stratigraphic analyses show that the Wan＇an carbonate platform exists mainly in transgressive and highstand system tracts.The sedimentary facies of single carbonate platform show ring construction in the plane view,and they are relatively narrow but regular,which may be divided into inner platform facies,fringing platform facies,foreslope facies（ramp and steep slope） and basin floor facies.However,the basin floor facies are found only in the eastern side of carbonate platform which may be related to the geological settings near the South China Sea.

关 键 词：海洋地质 碳酸盐台地 沉积 万安盆地 南海 

分 类 号：P736[天文地球—海洋地质]