基于重磁异常的嘉偕平顶山群构造区划特征研究  

Research on tectonic division in Jiaxie guyots based on gravity and magnetic anomalies

作　　者：马涛[1,2,3] 朱莹洁 杨永 纪晓琳 王丁丁[1,2,3] 刘金兰[1,2,3] 王万银 MA Tao;ZHU Ying-Jie;YANG Yong;JI Xiao-Lin;WANG Ding-Ding;LIU Jin-Lan;WANG Wan-Yin(Institute 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 University,Xi'an 710054,China;Department of Earth Sciences,Memorial University of Newfoundland,St.Johns',A1B3X5,Canada;Key Labo-ratory of Marine Mineral Resources,Guangzhou 510075,China;Ministry of Natural and Resources,Guangzhou Marine Geological Survey,Guangzhou 510075,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]自然资源部海底矿产资源重点实验室,广东广州510075 [6]中国地质调查局广州海洋地质调查局,广东广州510075

出　　处：《物探与化探》2020年第4期938-948,共11页Geophysical and Geochemical Exploration

基　　金：中国大洋“十三五”资源环境类课题“合同区海山地形单元识别与底质类型研究”(DY135⁃C1⁃1⁃03);国家重点研发计划项目“典型覆盖区航空地球物理技术示范与处理解释软件平台开发”项目(2017YFC0602200)之课题“航空地球物理数据综合处理解释方法研究及软件开发”(2017YFC0602202)。

摘　　要：西太平洋嘉偕平顶山群是中国富钴结壳合同区之一,蕴藏钴等战略性金属矿产资源。由于海山的局部构造对矿产资源的宏观分布具有重要的控制作用,因此研究海山的构造区划对于认识海山的形成过程及矿产资源勘探具有十分重要的意义。笔者利用嘉偕平顶山群的重、磁异常数据和地形数据,采用归一化总水平导数垂向导数(NVDR-THDR)断裂识别方法与曲率属性深度反演方法研究了嘉偕平顶山群的断裂分布特征,利用最小曲率位场分离方法研究了侧翼裂谷带及重力滑塌区的分布特征。研究表明,嘉偕平顶山群的断裂走向以NW和NE向为主,其次为NNW和NEE向;断裂视深度在3000~7000 m之间,且NW向断裂深度比NE向断裂的深度浅,NW向与NE向断裂相互交叉构成了呈雁行式排列的共轭剪切断裂带,为海山形成与岩墙侵入提供了重要通道。侧翼裂谷带是岩浆沿断裂通道侵入发育而成,使得海山呈现不规则的星形,因此通常位于海山地形不规则延伸地带。在侧翼裂谷带的发育过程中,由于受地震等构造活动的影响,会产生重力滑塌,在其两侧形成了滑塌沉积区,因此重力滑塌区通常位于海山陡峭边缘与侧翼裂谷带的两侧。本次研究成果为嘉偕平顶山群的形成过程及富钴结壳资源综合评价提供了重要的构造依据。The Jiaxie Guyots,located in the western Pacific and belongs to China’s contract areas of cobalt-rich ferromanganese crusts,contains strategic metal mineral resources,especially cobalt.Local structures of the guyots play an important controlling role in the macroscopic distribution of these resources,which leads to the research on the tectonic division of the guyots to understand their formation processes and explore mineral resources.In this paper,the gravity and magnetic data as well as topographic data were used to delineate fracture features of Jiaxie Guyots by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)edge recognition method and curvature attribute depth inversion method.The minimum curvature potential field separation method was used to delineate the distribution features of flank rift zones and gravity slide areas.The results show that faults of Jiaxie Guyots are mainly NW-and NE-trending,followed by NNW-and NEE-trending.The range of apparent depths of faults is between 3000 and 7000 m,and usually the depth of NW-trending faults are shallower than that of NE-trending faults.The faults of these two different directions intersect to form a conjugate shear fault zone,showing a geese-like arrangement,which provides magma volcanic conduits for seamount formation and rock wall intrusion.The flank rift zones are generally located in irregular terrain extensions of guyots,because they were shaped with magma intrusion and reshaped the seamount as irregularly appearances.During the development of flank rift zones,the gravity slide areas were also formed due to the influence of tectonic activities like earthquakes,and commonly they were located on sharp sides of margins and two sides of flank rift zones.The authors hold that this study of geological structures could give strong support to the study of the formation of Jiaxie Guyots and the comprehensive evaluation of cobalt-rich crust ferromanganese.

关 键 词：嘉偕平顶山群 NVDR-THDR 最小曲率 曲率属性 断裂 侧翼裂谷带 重力滑塌 

分 类 号：P631[天文地球—地质矿产勘探]