Thermochemical Sate of the Dharwar Craton from Multi-observable Probabilistic Inversion: Insights into its tectonic evolution and preservation

We present a thermodynamically constrained, fully probabilistic joint inversion approach for lithospheric structure that integrates multiple seismic and non-seismic datasets, including P- and S-wave receiver functions, Rayleigh-wave group and phase velocities, elevation, geoid anomaly, and surface heat flow. The complementary sensitivities of these observables, together with the explicit parameterization of mid-lithospheric discontinuities, allow internal lithospheric structure and the lithosphere–asthenosphere boundary to be resolved within a single unified inversion, reducing ambiguities inherent to single-dataset inversions. Numerical experiments are used to verify the internal consistency of the inversion framework, explore resolution trade-offs, and study how individual datasets constrain distinct thermochemical and structural parameters. Application to the Eastern Dharwar Craton yields tightly constrained Moho (~30 km) and LAB (~165 km) depths, a crustal architecture consistent with regional geology, a moderately depleted lithospheric mantle (consistent with xenolith evidence) and a thermally stable sublithospheric mantle. Importantly, the inversion resolves a sharp seismic velocity decrease at ~120 km depth that, when constrained by all datasets simultaneously, cannot be attributed to the lithosphere–asthenosphere boundary. Overall, our model provides a unified and physically consistent explanation for a broad suite of seismic and non-seismic observations, offers compelling evidence for a distinct mid-lithospheric discontinuity, long-term lithospheric stability, and helps reconcile previously conflicting interpretations of the deep structure beneath the Eastern Dharwar Craton.