Structural features and evolution of the Dniepr-Donets Basin, Ukraine, from regional seismic reflection profiles

A set of regional multichannel seismic reflection profiles crossing the Dniepr-Donets (DD) Basin in Ukraine, 100-200 km long and with a spacing of 10-15 km along strike illuminates the structure of the whole sedimentary cover. The rift, filled with pre- and syn-rift Devonian sequences and overlain with post-rife Carboniferous, Permian, Mesozoic and Palaeogene fill, is clearly seen on all sections. A 'basement' layer, previously identified as a Riphean rift succession by refraction seismic studies constitutes, in the main, strata of the Devonian and Early Carboniferous successions. The structure of the rift is characterised by large-scale rotational fault blocks and half-grabens, carried by basin-parallel to normal marginal faults or by major horst blocks. The total thickness of the Devonian and younger succession is up to 19 km in the study area. Post-rift Carboniferous and Mesozoic sediments cover the rift flanks and increase in thickness towards the rift axis and to the southeast. The cumulative thickness of the Carboniferous succession alone reaches 11 km, with the maximum depth of their base at about 15 km. Major post-rift tectonic events took place at the end of early Visean, in the middle of Serpukhovian, in Permian times, and between the Mesozoic and Cenozoic. Tectonic reactivations during Carboniferous and Early Permian times were most pronounced in the southeastern part of the DD Basin, while they were least pronounced in the northwestern part of the basin merging with the Pripyat Trough where they are barely observed. The most active development of salt structures and stocks corresponds with the periods of tectonic reactivation.