2-D versus 3-D Magnetotelluric Data Interpretation: A case study from the Dharwar craton, India

3-D modelling of the lithosphere of the Dharwar craton imaged several conductors in the crust and uppermost mantle region. The lithosphere can be divided into shallow and deeper lithospheres based on the conductivity anomalies present in the model. In the crustal region, vertical conductive features (~10 Ω-m) are present in the western and central part of the profile. A new finding of this 3-D study is the presence of an uppermost mantle conductor at the depth range of 100–200 km. The electrical properties of the conductors are comparable with the northward situated adjacent profiles conductors. The conductors present in the crust are due to sulphides and carbon-rich fluids. The low electrical resistivity in the deeper lithosphere is due to the refertilization of the mantle scar in the Cretaceous                                                                                                                                              

age by the passage of several hotspots. The conductor could be interpreted in the terms of the melt present in the region. In general, 2- D interpretation of 3-D magnetotelluric data acts as a guide to geological interpretation, but not in this case of the Dharwar craton. The concluding remark is that the 3-D image of the single profile data gives a better under- standing of the subsurface structures as compared to 2-D inversion results.

 

 

 

 

 

 

A plan view of the 3-D resistivity model obtained from the final 3-D inversion. The horizontal slices fit the component at various depths: middle crust (12 km, 15 km, and 18 km), near Moho (40 km) and lithospheric mantle (100 km, 140 km, 170 km, and 200 km).

 

 

 

 

 

Citation: Kusham, B. Pradeep Naick, A. Pratap, K. Naganjaneyulu, 2021. Tectonophysics 816 (2021) 229028,

https://doi.org/10.1016/j.tecto.2021.229028 external link