RomUkrSeis : seismic model of the crust and upper mantle across the Eastern Carpathians – from the Apuseni Mountains to the Ukrainian Shield

RomUkrSeis was carried out by a consortium of organisations, the Faculty of Geology and Geophysics and the Doctoral School of Geology of the University of Bucharest (Romania), the Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine (Kiev), the Institute of Geophysics of the Polish Academy of Sciences (Warsaw), the Deutsches GeoForschungsZentrum (Potsdam) and the School of Geosciences of the University of Aberdeen (Scotland). Financial support for drilling/shooting works on the territory of Romania came from S.C. Prospectiuni S.A. (with a special mention to former CEO Gehrig Stannard Schultz, currently at EPI Group, United Kingdom), Hunt Oil of Romania, Repsol Romania and on the territory of Ukraine from Ukrgeofizika. Participation of the Polish group in this work was supported within statutory activities No 3841/E-41/S/2014-2020 of the Ministry of Science and Higher Education of Poland. The authors express their sincere appreciation of the activities of many people who took part in field work and data acquisition. A large part of the instrumentation was provided by the Geophysical Instrument Pool of the Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany. Christian Haberland is thanked for his support and kindness facilitating the loan of this equipment to the RomUkrSeis consortium. The public domain packages GMT (Wessel and Smith, 1995) and Seismic Unix (Cohen and Stockwell Jr., 1997) were used in the preparation of maps and for seismic data processing. Tesseral Technologies Inc. (Calgary) developed the software for the full waveform modelling and we express our gratitude to their staff for technical support. The authors also wish to thank Professor Richard England (University of Leicester) and an anonymous reviewer for their constructive comments on an earlier version of this manuscript. This version is much improved as a result.Peer reviewedPostprin

Lithospheric Structure of the East European Craton at the Transition from Sarmatia to Fennoscandia Interpreted from the TTZ-South Seismic Profile (SE Poland to Ukraine)

The TTZ-South seismic profile follows the Teisseyre-Tornquist zone (TTZ) at the SW margin of the East European craton (EEC). Investigation results reveal the upper lithospheric structure as representing the NW-vergent, NE-SW striking overthrust-type, Paleoproterozoic (~1.84–1.8 Ga) Fennoscandia-Sarmatia suture. The Sarmatian segment of the EEC comprises two crustal-scale tectonic thrust slices: the Moldavo-Podolian and Lublino-Volhynian basement units, overriding the northerly located Lysogoro-Radomian unit of Fennoscandian affinity. The combined results of the TTZ-South and other nearby deep seismic profiles are consistent with a continuation of the EEC cratonic basement across the TTZ to the SW and its plunging into the deep substratum of the adjacent Paleozoic platform. Extensional deformation responsible for the formation of the mid to late Proterozoic (~1.4–0.6 Ga), SW-NE trending Orsha-Volhynia rift basin is probably also recorded. The thick Ediacaran succession deposited in the rift was later tectonically thickened due to Variscan deformation. The Moho depth varies between 37 and 49 km, resulting in the thinnest crust in the SE, sharp depth changes across the TTZ, and slow shallowing from 49 to 43 km to the NW. The abrupt Moho depth increase from 43 to 49 km is considered to reflect the overlying lower crust tectonic duplication within the suture zone