基于重力资料的马达加斯加岛及邻区盆地构造单元分布特征  

A study of the distribution characteristics of basin tectonic units based on gravity data in Madagascar and its adjacent basins

作　　者：王学发 王万银[1,2,3] 马杰[1,2,3] 杨敏 梁建设[5] 邱春光 王丁丁 纪晓琳 刘金兰 WANG Xue-Fa;WANG Wan-Yin;MA Jie;YANG Min;LIANG Jian-She;QIU Chun-Guang;WANG Ding-Ding;JI Xiao-Lin;LIU Jin-Lan(Insititute of Gravity and Magnetic Technology,Chang'an University,Xi'an 710054,China;College of Geology Engineering and Geomatics,Chang'an University,Xi'an 710054,China;Key Laboratory of Western China's Mineral Resources and Geological Engineering,Ministry of Education,Chang'an U-niversity,Xi'an 710054,China;Department of Earth Sciences,Memorial University of Newfoundland,St.Johns',A1B3X5,Canada;Cnooc Research Institute Limited,Beijing 100027,China)

机构地区：[1]长安大学重磁方法技术研究所,陕西西安710054 [2]长安大学地质工程与测绘学院,陕西西安710054 [3]长安大学西部矿产资源与地质工程教育部重点实验室,陕西西安710054 [4]纽芬兰纪念大学地球科学系,加拿大圣约翰斯市A1B3X5 [5]中海油研究总院有限责任公司,北京100027

出　　处：《物探与化探》2020年第4期928-937,共10页Geophysical and Geochemical Exploration

基　　金：国家科技重大专项“大型油气田及煤层气开发”专项项目“海外重点区勘探开发关键技术研究”“非洲重点区油气勘探潜力综合评价”(2017ZX05032⁃002)。

摘　　要：随着非洲油气资源对外开放程度的加大,为我国海外石油勘探提供了机遇。非洲低勘探程度区油气地质资料匮乏,矿产资源丰富,为了利用地球物理资料研究马达加斯加岛构造特征,本文搜集了研究区已有的重力资料。根据布格重力异常,采用沉积层重力异常提取、最小曲率位场分离、归一化总水平导数垂向导数(NVDR-THDR)、曲率属性深度反演等识别出断裂信息和盆地边界,结合地质资料、地球物理资料,分析了主要断裂的地质及地球物理特征,确定了研究区内的断裂特征和盆地分布。通过研究,推断了研究区内一级断裂9条,二级断裂11条,断裂走向主要为NNE向、NE向和近NS向;结合断裂分布和前人研究现状,重新划分了马达加斯加岛塔姆塔夫盆地、穆伦达瓦盆地和马任加盆地的边界及内部隆坳构造格架,识别了7个坳陷和3个隆起,隆坳构造呈"两坳夹一隆"带状分布。该研究成果可以为马达加斯加岛及邻区油气和矿产资源勘探提供地球物理依据。With offering the increasing opening exploration of oil and gas resources to the oversea exploration companies in Africa which remains in an early exploration stage,a good opportunity is provided for the companies in China.In this study,the gravity data of this research area were collected in order to study the tectonic characteristics of Malagasy Island,which has insufficient oil and gas geological data but abundant mineral resources.The faults and the boundaries of this basin were identified according to the response of the gravity anomaly to the sediments by the separation method of the minimum curvature,the vertical derivative of the normalized total horizontal derivative(NVDR-THDR)and the inversion of the depth of the curvature attribute,with Bouguer gravity anomaly.The geological and geophysical characteristics of the main faults were analyzed,and the distribution characteristics of faults and basins were determined,which were based on the geological and geophysical data.According to this research,there are 9 primary faults and 11 secondary faults inferred in this study area trending NNE,NE and nearly NS.The tectonics of Tamatave Basin,Morondava Basin and Majunga Basin were re-divided into 7 depressions and 3 uplifts combined with the distribution of faults from this study and previous studies,which are shown as a zonal distribution like"two depressions with one uplift".This research can provide geophysical information for exploration of oil,gas and mineral resources in Madagascar and its adjacent regions.

关 键 词：马达加斯加岛 重力异常 断裂分布 构造单元 

分 类 号：P631[天文地球—地质矿产勘探]