摘要
琼北地区广泛发育第四纪火山,然而其稳定性及与长流-仙沟断裂的关系仍存在争议.在琼北第四纪火山区,获得了覆盖雷虎岭火山系统的184个大地电磁测深数据.相位张量分析指示了电各向异性的存在,采用一维各向异性反演获得了地下电各向异性结构.结果显示浅部(~1~5 km)最小电阻率方向近平行于长流-仙沟断裂;而深部(~5~15 km)近南北向,与断裂斜交.研究表明长流-仙沟断裂不是深大断裂,且并不控制深部岩浆路径;深部各向异性可能反映了一个存储含盐流体的高孔隙度区域,其来源于更深位置的部分熔融,而这指示雷虎岭火山系统当前处于休眠状态.
Quaternary volcanoes are widely distributed in the North Hainan island.However,the stability and the relationship with the Changliu-Xiangou fault remain controversial.184 magnetotelluric data covering the Lei-Hu-Ling volcanic system were acquired in the Quaternary volcanic region of North Hainan island in this study.The analysis of phase tensors indicates the existence of electrical anisotropy,and consequently the electrical structure was obtained by 1 D anisotropic inversion.The inversion results show that the minimum resistivity direction is almost parallel to the Changliu-Xiangou fault in the shallow(~1-5 km)and strikes south-north in the deep(~5-15 km),which is oblique to the fault.It is found that the Changliu-Xiangou fault is not a deep-large fault and does not control the deeper magmas path.We prefer to attribute the deep anisotropy to accumulation of high-salinity fluids in the storage zone with high porosity,which is associated with the transportation of magmatic fluids and volatiles supplied by a partial melting zone at greater depths.It is concluded that the Lei-Hu-Ling volcanic system is dormant at present.
作者
刘营
胡道功
许顺芳
李子梁
陈超
Liu Ying;Hu Daogong;Xu Shunfang;Li Ziliang;Chen Chao(Hubei Subsurface Multi?Scale Imaging Key Laboratory,Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2020年第1期330-340,共11页
Earth Science
基金
国家自然科学基金项目(No.41904079)
中国地质调查局项目(Nos.121201104000150002,DD20190306).
关键词
大地电磁
电各向异性
长流-仙沟断裂
第四纪火山
琼北
地球物理
magnetotellurics
electrical anisotropy
Changliu-Xiangou fault
Quaternary volcano
North Hainan island
geophysics
