| 琼北第四纪火山区电各向异性结构及其地质意义 |
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| 引用本文： | 刘营,胡道功,许顺芳,李子梁,陈超.琼北第四纪火山区电各向异性结构及其地质意义[J].地球科学,2020,45(1):330-340. |
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| 作者姓名： | 刘营 胡道功 许顺芳 李子梁 陈超 |
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| 作者单位： | 1.中国地质大学地球物理与空间信息学院, 地球内部多尺度成像湖北省重点实验室, 湖北武汉 430074 |
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| 基金项目： | 国家自然科学基金项目41904079中国地质调查局项目121201104000150002中国地质调查局项目DD20190306 |
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| 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.
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| 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 |
| 收稿时间： | 2018-10-09 |
Electrical Anisotropic Structure in the Quaternary Volcanic Region of North Hainan Island and Its Geological Implications |
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| Abstract: | 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 1D 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. |
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