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Unveiling the crustal structure beneath the Chotanagpur Granite Gneiss Complex, eastern India: Interpretation from the 3-D magnetotelluric study.

Naganjaneyulu K, Naick BP, Kusham, Pratap A, Bhargavi VP.

PHYSICS OF THE EARTH AND PLANETARY INTERIORS

https://doi.org/10.1016/j.pepi.2025.107406 

The Chotanagpur Granite Gneiss Complex (CGGC) is a key geological unit in eastern India. The 3-D magnetotelluric investigation reveals a resistive upper crust due to granite and gneiss composition, while low-resistivity (~10 Ω-m) anomalies (C1, C2, and C3) in the mid-crust indicate past magmatic fluid pathways linked to subduction processes.

(a) Geological map with locations of MT sites and major cities. The Bouguer gravity anomaly contour map for the study region is also shown with station location. Heat flow values (mW/m2) and mineral deposits also plotted in the map. (b) Final 3-D resistivity model with anomalies (C1, C2, and C3).

These fluids likely contributed to carbon enrichment and mineralization. No deep-seated faults were identified; however, mid-crustal faults and layered structures were observed. The findings enhance understanding of crustal evolution, tectono-thermal events, and metallogeny in this mineral-rich Precambrian terrane.

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