The Variscan foreland in Poland revisited: new data and new concepts

Abstract

As so ci ate Ed i tor: Leszek Marks An ear lier con cept of the Variscan fore land in Po land (Narkiewicz, 2007) is re con sid ered in the light of new strati graphic, tectonic and geo phys i cal ev i dence, pro vid ing new data on De vo nian sed i men ta tion, Car bon if er ous magmatism and the deep crustal struc ture of SE Po land. Re gional com par i sons with the tec tonic evo lu tion of Cen tral Eu rope and the Black Sea re gion show that the sub si dence pat tern in the fore land was con trolled by al ter nat ing phases of ac cel er ated con ver gence and tectonic stand still along the south ern mar gin of Euramerica. In par tic u lar, the Bretonian (De vo nian/Car bon if er ous) compressional de for ma tion re sulted from in ten si fied orogenic con ver gence in the West-Cen tral European Variscides lead ing to clo sure of the Saxo-Thuringian Ba sin and East-Sudetic back-arc ba sin. An other turn ing point in the re gional tectonosedimentary de vel op ment around the Mississippian-Pennsylvanian bound ary was prob a bly re lated to the ter mi nation of terrane col li sion in the Black Sea re gion. Late Penn syl va nian ba sin in ver sion was as so ci ated with a roughly N-S tectonic short en ing. This was partly due to dis place ment along pre-ex ist ing base ment dis con ti nu ities com pris ing re ac ti vated Cal edo nian su tures that also pre-de ter mined the Devonian-Carboniferous ba sin bound aries. Con se quently, deeply-rooted tec tonic zones, in clud ing the Kraków-Lubliniec and Holy Cross faults and the Teisseyre-Tornquist Zone, fo cussed max i mum compressional and transpressional de for ma tion and as so ci ated up lift. Such a con cept of ter mi nal Variscan tectonism, termed here the "de coup led model", is dis cussed with ref er ence to the re cently pro posed "cou pled model". The lat ter assumes a wide ex tent of the Variscan Orogen, reach ing as far as the mar ginal Radom-Kraoenik Fold-and-Thrust Belt linked with the Bo he mian Mas sif through a ma jor basal de tach ment. It is con cluded that the "de coup led model" is more con sis tent with the doc u mented seis mic and struc tural ev i dence as well as with the pres ent knowl edge of the heterogeneous pre-De vonian base ment in south ern Po land.

Together but separate: decoupled Variscan (late Carboniferous) and Alpine (Late Cretaceous – Paleogene) inversion tectonics in NW Poland

“…Both inversion structures are compatible with certain elements of the classic inversion model by Bally (1984), but collectively form a complex, superimposed multilayer decoupled inversion system. Krzywiec and Kufrasa, submitted, compiled after Mazur et al 2020, Narkiewicz 2007, 2020, Opluštil and Cleal 2007Ziegler 1990, Catalan et al 2020. Grey area: present-day post-erosional extent of the Carboniferous basin.…”

“…Final emplacement of the Variscan fold-and-thrust belt onto its foreland plate took place in the late Carboniferous (Kröner et al, 2008;Mazur et al, 2010Mazur et al, , 2020. It led to the regional flexure of the foreland plate and formation of extensive Carboniferous foreland basin filled with a thick synorogenic sedimentary succession (Burgess and Gayer, 2000;Deckers and Rombaut, 2021;Franke, 2014;Kombrink et al, 2010;Leveridge and Hartley, 2006;Maynard et al, 1997;McCann, 1999;McCann et al, 2008;Narkiewicz, 2007Narkiewicz, , 2020Opluštil and Cleal, 2007;Tomek et al, 2019). Final stages of evolution of the external Variscan fold-and-thrust belt were associated with a widespread inversion of Palaeozoic basins located within its foreland (e.g., Corfield et al, 1996;Glen et al, 2005;Peace & Besly, 1997;Pharaoh et al 2020;Shail & Leveridge 2009;Smith, 1999;von Hartmann, 2003).…”

“…3). This succession is composed o f mainly clastic and carbonate sediments, with subordinate evaporites (Lipiec and Matyja, 1998;Narkiewicz, 2007Narkiewicz, , 2020 https://doi.org/10.5194/se-2021-105 Preprint. Discussion started: 2 September 2021 c Author(s) 2021.…”

Reply on RC1

“…Both inversion structures are compatible with certain elements of the classic inversion model by Bally (1984), but collectively form a complex, superimposed multilayer decoupled inversion system. Krzywiec and Kufrasa, submitted, compiled after Mazur et al 2020, Narkiewicz 2007, 2020, Opluštil and Cleal 2007Ziegler 1990, Catalan et al 2020. Grey area: present-day post-erosional extent of the Carboniferous basin.…”

The palynology of the Middle–Upper Devonian (Givetian–Frasnian) in the Łysogóry-Radom and Lublin basins, south-central Poland

“…This event is widely recognised within the marine realm, but records of changes that took place in the terrestrial environment are scarce (Marshall et al 2011;Turnau 2014). The Łysog ory-Radom and Lublin basins during the Devonian formed part of a wide tropical belt of a shelf margin of the Laurussia continent, and that gives us an opportunity to look into the interval of noticeable palaeoenvironmental changes related to eustasy (Narkiewicz 2007;Narkiewicz et al 2011).…”