Integrated geological-geophysical characterization of the zone of the Kherson—Smolensk transregional tectonic suture — deep long-lived magma- and fluid-conducting channel

Abstract

The transregional Kherson—Smolensk suture has been established to be located between large meridional faults of the crystalline crust of the Ukrainian Shield (USh) in a strip of 50—70 km width and separates two microplates of different composition of the Precambrian basement. It is traced by subcrustal mantle heterogeneity in the lithosphere and a change in the relief of the main geodynamic boundary. The suture controls the USh large multiphase magmatic massifs and manifestation of the basic mafic magmatism in the Dniepr-Donets Depressin (DDD), which age decreases from south to north from the Early Proterozoic in the shield to the Devonian in the depression. On both sides of it, the crystalline crust differs in a set of parameters including a zone of low velocities in the area of the Novokonstantinovsky ore field of the USh to the east of the Kherson—Smolensk suture, where from DSS data its maximum thickness is 10—15 km in the upper crust. It appears to bea source of abiogenic hydrogen manifestations recorded by mining operations on this field. The Kherson—Smolensk suture, being a transregional mantle feature, unites the existing hydrocarbon manifestation in the USh with the promising hydrocarbon areas of the DDD. The inhomogeneities of the crystalline crust and the uppermost mantle give strong evidences to classify reasonably the transregional tectonic suture Kherson—Smolensk as a powerful mantle long-lived magmatic and fluid-conducting channel. Ores hows and modern degassing of methane are related to it, with methane beingmain greenhouse gas.