EVOLUTION OF THE SOUTHERN MARGIN OF THE DONBAS (UKRAINE)

EVOLUTION OF THE SOUTHERN MARGIN OF THE DONBAS (UKRAINE) FROM DEVONIAN TO EARLY CARBONIFEROUS TIMES.

A Devonian-early Carboniferous succession comprising thick clastic and carbonate sediments with interbedded volcanics was examined along the southern margin of the Donbas Foldbelt, Ukraine. Following initial rifting and subsidence, a continental (fluvial, lacustrine) succession was established. This first phase of syn-rift activity (Eifelian) was accompanied by the intrusion of basalts. In late Givetian-early Famennian times half graben development was pronounced and a series of E-W-trending half-grabens were formed. Coeval volcanic activity was marked. Subsequent basin subsidence led to the establishment of a broad carbonate platform across the region (Upper Famennian-Tournaisian-early Visean). Magma chamber swelling led to uplift, partial exposure and karstification of the platform. This was accompanied by trachyte intrusion and extrusion. Subsidence and related sea level rise led to the deposition of a chert-rich unit across the region. Renewed tectonic activity along the main basin-bounding fault resulted in the deformation of this unit.