Complex interpretation of seismic data along the profile of the CMPV-GSN Sinelnikovo-Chuguev

The complex interpretation of seismic data along DSS -CMRW profile Sinelnikovo - Chuguev was done. The crust along the profile has found a complex layered-block structure with differences throughout the depth of all section in three major structural elements: Ukrainian Shield, Dnieper-Donets depression (DDD) and the Voronezh Massif. Sedimentary cover is most powerful in the DDD. It consists of two structural floors: upper (divided into layers of low velocity) and homogenous lower with high seismic waves velocities. The earth crust consists of upper and lower parts. Those parts are different in reflective properties and velocity characteristics which are varying in depth and along the profile. The crust’s thickness is 33-40 km. The upper mantle reflections may be as-sociated with possible more ancient another Moho boundary. Major structural faults in the upper floor of DDD are laying the mantle and, consequently, can provide the channels for the flow of hydrocarbons from deep parts of the sedimentary cover. Axial part of the mantle diaper is shifted northward relative to the center of the basin, wich suggests preferential southwestern disclosure of the Dnieper-Donets avlakogene

Seismic model of the crust and upper mantle in the Scythian Platform: the DOBRE-5 profile across the north western Black Sea and the Crimean Peninsula

International audienceThe Scythian Platform (ScP) with a heterogeneous basement of Baikalian–Variscan–Cimmerian age is located between the East European Craton (EEC) on the north and the Crimean–Caucasus orogenic belt and the Black Sea (BS) Basin on the south. In order to get new constrains on the basin architecture and crustal structure of the ScP and a better understanding of the tectonic processes and evolution of the southern margin of the EEC during Mesozoic and Cenozoic time, a 630-km-long seismic wide-angle refraction and reflection (WARR) profile DOBRE-5 was acquired in 2011 October. It crosses in a W–E direction the Fore-Dobrudja Trough, the Odessa Shelf of the BS and the Crimean Plain. The field acquisition included eight chemical shot points located every 50 km and recorded by 215 stations placed every ∼2.0 km on the land. In addition, the offshore data from existing profile 26, placed in the Odessa Shelf, were used. The obtained seismic model shows clear lateral segmentation of the crust within the study region on four domains: the Fore-Dobrudja Domain (km 20–160), an offshore domain of the Karkinit Trough at the Odessa Shelf of the BS (km 160–360), an onshore domain of the Central Crimean Uplift (Crimean Plain, km 360–520) and the Indolo-Kuban Trough at the Kerch Peninsula (km 520–620) that is the easternmost part of the Crimea. Two contrasting domains of the ScP within the central part of the DOBRE-5 profile, the Karkinit Trough and the Central Crimean Uplift, may represent different stages of the ScP formation. A deep Karkinit Trough with an underlying high-velocity (>7.16 km s−1) lower crust body suggests its rifting-related origin during Early Cretaceous time. The Central Crimean Uplift represents a thick (up to 47 km) crustal domain consisting of three layers with velocities 5.8–6.4, 6.5–6.6 and 6.7–7.0 km s−1, which could be evidence of this part of the ScP originating on the crust of Precambrian craton (EEC). The thick heterogeneous basement of the Central Crimean Uplift shows inclusions of granitic bodies associated with magmatic activity related with Variscan orogeny within the ScP. General bending and crustal scale buckling of the Central Crimean Uplift with a wavelength of 230 km could be an effect of the Alpine compressional tectonics in the adjacent Crimean Mountains. The extended/rifted continental margin of the ScP (EEC) at the Odessa Shelf and buckling/uplifted domain of the Central Crimean Uplift affected by compressional tectonics, are separated by the N–S oriented Western Crimean Fault. The crust of the southern margin of the EEC is separated from the ScP, which originated on the EEC crust tectonised and reworked during the Palaeozoic–Mesozoic, by the crustal fault of ∼W–E orientation, which corresponds with the Golitsyn Fault observed at the surface between the EEC and the ScP. The Fore-Dobrudja Domain with a thick (>10 km) heterogeneous basement and two subhorizontal layers in the crystalline crust (with velocities 6.2–6.3 and 6.4–6.65 km s−1) differs from the ScP crust and its origin could be very similar to that of the Trans-European Suture Zone and Palaeozoic West European Platform