Deciphering Fine Electrical Conductivity Structures in the Crust From MT Data Using the Equivalent Conductivity Formula
Deciphering Fine Electrical Conductivity Structures in the Crust From MT Data Using the Equivalent Conductivity Formula
复制标题
使用等效电导率公式从 MT 数据解读地壳中的精细电导率结构
DOI：
10.1029/2021jb022519
复制
发表时间：
2021-09
期刊：
影响因子：
--
通讯作者：
Ying Liu
中科院分区：
文献类型：
--
作者：
Shuyu Liu;Yixian Xu;Bo Yang;Zeqiu Guo;Yuan Shi;Ying Liu
地震反射探测到的下地壳精细结构可以在各种地质过程中形成，其电阻率特性可以为研究岩石圈的地球动力学过程提供重要的信息。大地电磁（MT）法是目前研究岩石圈电阻率结构的常用方法，但其分辨率不高，难以分辨地壳深部的微小非均匀性。为了恢复精细的电阻率结构，我们提出了一种策略，其等效电阻率的基础上，定义的精细结构和倒置的体积电阻率之间的关系。因此，我们首先以>95%的准确度制定了3D层压结构的等效电阻率。该方法利用大地电磁测深资料反演的体电阻率反演精细电阻率结构，反演的等效电阻率与反演的等效电阻率相匹配。通过对该方法在盆岭省下地壳电性分析和层状构造成因分析中的应用，验证了该方法的可行性。由一维各向异性反演的体电阻率反演得到层状岩体的电阻率在0.15-0.3 Ωm之间，与硅酸盐熔体的电阻率一致，表明层状岩体可能是熔体分数大于50%的岩浆房，这一结论也得到了地震和地质证据的支持。实例研究表明，这种基于等效性的方法可以成功地从大地电磁测深数据中恢复精细电阻率结构。
Fine structures in the lower crust sounded by seismic reflection can be formed in various geological processes and their electrical resistivity properties can provide significant insights into the geodynamic processes of the lithosphere. The magnetotelluric (MT) method is popular for imaging the electrical resistivity structure of the lithosphere; however, it lacks high resolution to resolve the small heterogeneities in deep crust. To recover the fine electrical resistivity structures, we propose a strategy based on their equivalent resistivity that defines the relationship between the fine structures and the inverted bulk resistivities. Thus, we first formulated the equivalent resistivity for a 3‐D laminated structure with >95% accuracy. In this strategy, the bulk resistivity inverted from MT data is used to retrieve the fine resistivity structures, for which the corresponding equivalent resistivities should match with the inverted resistivities. The strategy was tested to demonstrate its feasibility for analyzing the electrical property and the cause of lamellae in the lower crust of the Basin and Range Province. From the bulk resistivities of 1‐D anisotropic inversion, we retrieved the resistivity of lamellae that was in the range of 0.15–0.3 Ωm and coincident with the resistivity of silicate melts, implying that the lamellae are probably magma chambers with >50% melt fraction, which is also supported by seismic and geological evidences. Our case study demonstrated that this strategy based on equivalence can be successfully used to recover the fine resistivity structures from MT data.
登录
查看更多内容
影响因子：
2.7
作者：
S. Wickham
通讯作者：
S. Wickham
影响因子：
2.9
作者：
A. Vauchez;A. Tommasi;D. Mainprice
通讯作者：
A. Vauchez;A. Tommasi;D. Mainprice
影响因子：
2.8
作者：
A. Merzer;S. Klemperer
通讯作者：
A. Merzer;S. Klemperer
影响因子：
--
作者：
C. Jarchow;G. A. Thompson;R. Catchings;W. Mooney
通讯作者：
C. Jarchow;G. A. Thompson;R. Catchings;W. Mooney
DOI：
10.1144/gsl.sp.1986.024.01.03
发表时间：
1986
期刊：
Geological Society, London, Special Publications
影响因子：
--
作者：
D. Matthews
通讯作者：
D. Matthews