The deep structure of the Dobrogea and Fore-Dobrogea trough as an indication of the development of the Trans-European suture zone

Abstract

The tectonic structure of Dobrogea and Fore-Dobrogea trough are considered on the basis of geological and geophysical data. Dobrogea and Fore-Dobrogea trough are the key areas for understanding of Central Europe geodynamics, because they are located within the southeastern part of the Trans-European Suture Zone (TESZ), which is available here for direct field research. The current position of these units in the foreland of the Carpathians and on the north-eastern coast of the Black Sea makes them a link that connects the Pannonian-Carpathian region and Crimean-Black Sea region. The deep structure of the study area is described by the velocity models of wide-angle reflection and refraction (WARR) profiles VRANCEA-2001, DOBRE-4 and PANCAKE. Dobrogea is a system of northeastern vergence overthrusts, separated by a series of large faults. These faults, most important of which is Pecenega-Camena Fault, are part of the southern branch of the TESZ. The width of the Dobrogea thrust zone is about 60 km and close to the width of the thrust zone along PANCAKE profile. The modern fold and thrust structure of Dobrogea was formed on the place of the paleopaleozoic suture in Cimmerian tectonic stage (Upper Jurassic—Lower Cretaceous) and activated in the Early-Alpine stage (Upper Cretaceous—Paleogene), being later than the Jurassic, and earlier than the Alpine thrusting in the Pannonian-Carpathian region. Taking into consideration the geological and geophysical similarity of Rava-Ruska and North-Dobrogea elements of the East European platform, as well as similarity of the Inner zone of the Lviv Paleozoic trough and the Fore-Dobrogea trough, it can be suggested that within the study area, the northeast boundary of the TESZ passes close to the surface beneath the Fore-Dobrogea trough, while the southwest boundary coinside with the Peceneaga-Camena Fault and may even cross it at the boundary of the upper and middle crust. According to the data of the WARR profiles DOBRE-4 and PANCAKE, the TESZ is considered not to be vertical zone, but gently dipping system of overthrusts separated the East European platform from the Western European and Moesian platforms.