南海北部陆缘珠江口盆地岩石圈热结构  

Lithospheric thermal structure of the Pearl River Mouth Basin,northern South China Sea

作　　者：唐晓音[1] 黄少鹏[1] 张功成 杨树春 胡圣标[3] TANG XiaoYin;HUANG ShaoPeng;ZHANG GongCheng;YANG ShuChun;HU ShengBiao(School of Human Settlements and Civil Engineering,Xi′an Jiaotong University,Xi′an 710049,China;CNOOC Research Institute,Beijing 100027,China;State Kay Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences, Beijing 100029,China)

机构地区：[1]西安交通大学人居环境与建筑工程学院,西安710049 [2]中海油研究总院,北京100027 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2018年第9期3749-3759,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41602251);中国博士后基金(2015M582636)联合资助

摘　　要：沉积盆地岩石圈热结构特征是岩石圈构造-热演化过程的综合反映和盆地热史恢复的约束条件,对盆地动力学研究和油气资源评价具有重要意义.由于海洋勘探难度大、勘探程度低,相对于大陆地区,边缘海盆地比较缺乏岩石圈热结构方面的研究.本文在收集整理珠江口盆地及邻区大地热流数据的基础上,补充收录了自2003年以来发表的新数据,绘制了研究区最新版的大地热流等值线图;基于中美合作双船地震剖面揭示的深部地壳结构计算了研究区的壳-幔热流、深部温度以及"热"岩石圈厚度.研究表明,珠江口盆地地壳热流介于18.7~28.6mW·m^(-2),地幔热流介于36.9~91.4mW·m^(-2),壳幔热流比值0.23~0.75;由陆架、陆坡至中央海盆,在地壳热流逐渐减小的情况下地表热流逐渐递增,说明地表热流分布主要受深部热作用控制;盆地"热"岩石圈厚度介于34.0~87.2km,平均65.5km,反映出显著拉张减薄的特征.The lithospheric thermal structure is resulted from lithospheric tectono-thermal evolution.It provides fundamental constraints on thermal history reconstruction which is of great importance to basin dynamics investigation and hydrocarbon resources assessment.Due to the fact that conducting geological exploration offshore is much more difficult than inland,lithospheric thermal structure studies are less abundant in the continental margin basins than in the continental areas in China.In this study,we update the existing heat flow database of the Pearl River Mouth Basin of northern South China Sea with data published since 2003 to produce a new heat flow map for the study area.We further analyze the lithospheric thermal structure of the Pearl River Mouth Basin based on the updated heat flow database and the existing seismic crustal structure data acquired by the project“USA-China Joint Investigation on Marine Geology of South China Sea”.Result shows that the crustal heat flow of the study area is 18.7~28.6 mW·m-2,while the mantle heat flow ranges from 36.9 to 91.4 mW·m-2.The ratio of crustal heat flow to mantle heat flow varies between 0.23 and 0.75.From the continental shelf area to the ocean-continental transition zone,the surface heat flow appears to increase while crustal heat flow decrease,implying that the mantle heat flow is the predominant contributor to the surface heat flow in the Pearl River Mouth Basin.The thermal lithospheric thickness of the study area turns out to be 34.0~87.2 km,with the average value of 65.5 km,showing that the Pearl River Mouth Basin is of characteristics of lithosphere stretching and thinning.

关 键 词：壳-幔热流 深部温度 “热”岩石圈厚度 珠江口盆地 

分 类 号：P314[天文地球—固体地球物理学]