Large variation of Curie depth and lithospheric thickness beneath the Indian subcontinent and a case for magnetothermometry

A first order estimate of Curie depth and lithospheric thickness variation beneath the Indian region has been obtained using the available geothermic data. The Curie depth is found to vary from 18 to 68 km and the lithospheric thickness from 38 to 186 km. These estimates conform well with the MAGS AT and seismological findings. Both the parameters exhibit covariancy and suggest the possibility of approximating heat flow values and lithospheric thickness in geothermally uncharted areas using Curie point geotherm depths derived from air/satellite-borne magnetic anomalies. Interestingly, the areas with shallow Curie depth and lithospheric thickness are found to be associated with a thin crust, higher heat flow, higher geothermal gradients and positive gravity anomalies, and vice versa. Large thickness estimate of magnetic crustal layer, extending below the Moho, demands a new conceptual understanding. The study has brought out a good case for wider use of magneto-thermometry and provides understanding of the geodynamic evolution of the Indian subcontinent.