Lithospheric electrical imaging of the Deccan trap covered region of western India
Lithospheric electrical imaging of the Deccan trap covered region of western India
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DOI：
10.1029/2007jb005572
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发表时间：
2009-01
期刊：
影响因子：
--
通讯作者：
P. Patro;S. Sarma
中科院分区：
文献类型：
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作者：
P. Patro;S. Sarma
我们在这里介绍的大地电磁法（MT）研究的结果进行了沿着330公里长的东北-西南走向的导线从道拉塔巴德在东北端的Koyna在西南端的德干火山省（DVP）在印度西部。对沿沿着该导线以及该区域其他MT导线获得的二维MT建模结果进行了检查，并将其与深地震测深、三维地震层析成像和热流研究的结果相结合。从MT模型推导出的深部地电剖面指出了两层岩石圈地幔结构，上部具有非常高的电阻层（数千欧姆m），底部具有相对导电的电阻层（几十欧姆m到几百欧姆m）。岩石圈电性结构被推断与组成的变化与一个枯竭的岩石圈上地幔在达尔瓦尔克拉通。该研究的一个令人印象深刻的特征是，在DVP上方从Sangole到Partur的MT导线中段，在80-120 km的深度范围内存在一个定义明确的岩石圈上地幔导体。包括上地幔导体的存在，该地区的电气特性显示出与其他类似的磁共振区，如加拿大西北部的奴隶和上级磁共振区的密切相似之处。
We present here the results of magnetotelluric (MT) studies carried out along a 330 km long NE‐SW trending traverse from Daulatabad at the northeastern end to Koyna on the southwestern end across the Deccan volcanic province (DVP) in western India. The 2‐D MT modeling results obtained along this traverse together with those from other MT traverses in this area are examined and integrated with the results from deep seismic sounding, 3‐D teleseismic tomography, and heat flow studies. The deep geoelectric section as deduced from MT models point out to a two layered lithospheric mantle structures with an upper very high‐resistive layer (several thousands of ohm m) and a bottom relatively conductive one (a few tens of ohm m to a few hundred ohm m). The lithospheric electrical structure is inferred to be linked to compositional changes associated with a depleted lithospheric upper mantle in the Dharwar craton. An impressive feature that the study has brought out is the presence of a well‐defined lithospheric upper mantle conductor in the depth range of 80–120 km limited to the middle segment of the MT traverse from Sangole to Partur over the DVP. The electrical characterization of the region including the presence of upper mantle conductor shows close similarities with that of other similar cratonic regions like the Slave and Superior cratons in northwestern Canada.