Evaluation of crystallization temperatures of mineral paragenesis in consolidated crust and uppermost mantle from explosion seismology data

In terms of the general endogeneous evolution of the lithosphere, the continental crystalline crust and the uppermost mantle, formed by regional metamorphic and magmatic processes, show mineral paragenesis stratification, expressed by a regular mineral sequence. The continuous macrolayering of mineral paragenesis through lithospheric depth profile is caused by phase transformations and variations in composition of complex natural systems, and affects the vertical distribution of seismic velocities,V_p,V_s, and other physical parameters.To evaluate palaeotemperatures (crystallization temperatures of mineral paragenesis), consistentV_pandV_s(Z) velocity models for the consolidated crust of two regionally separated areas of different geological structures — Precambrian shield (Voronezh Massif) and a young fold-mountain structure in the central part of the Transasian orogeneous belt (Himalaya) — are used as starting data.The velocity models are recalculated into (Z) and (Z) profiles (Z) being the seismic parameter. (Z) the Debye temperature). These, according to Debye theory, allow the determination of variations in entropy, thermodynamic and temperature gradients at the time of crustal generation.For the two regions chosen, palaeotemperature distributions are eventually calculated for the depth intervals given by velocity profiles. Crystallization temperatures calculated from seismic data show good agrrement with the values obtained from mineralogical thermobarometry.