Contrasting tectonic and sedimentary history of the central and eastern parts of the Polish Carpathian foredeep basin Ð results of seismic data interpretation P. Krzywiec * Polish Geological Institute, ul. Rakowiecka 4, 00-975 Warsaw, Poland Received 1 February 1998; received in revised form 27 July 1999; accepted 27 July 1999 Abstract Polish Carpathian foredeep basin (PCFB) is located at the junction between Western and Eastern European Platforms. Such location caused different evolution of various parts of this basin. In the central part of the PCFB growth fault-propagation folds related to latest (Badenian) stages of thrusting in this segment of the Carpathians developed. Only minor normal faulting related to Miocene reactivation of older basement faults was detected. Paleovalleys mapped within the Mesozoic basement were interpreted as Palaeogene tectonically controlled erosional features developed after inversion of the Polish Trough. In the central PCFB post-evaporitic sediments were supplied into the foredeep basin from south, from the eroded Carpathians. In the eastern part of the PCFB, a system of large normal faults related to Miocene ¯exure-induced reactivation of inherited Mesozoic faults was identi®ed. Within the hangingwall of this system, reverse faults, rotated blocks and basement pop-up structures were described. Their formation was related to combined effect of compressional stresses transferred from the Carpathian collision zone and reactivation of older large-scale fault caused by both ¯exural extension and strike-slip movements. During deposition of the Miocene foredeep sediments differential compaction also played an important role. Gentle onlap of the Middle Badenian evaporites by post-evaporitic sediments towards the NW was interpreted as a result of tectonically driven relative sea-level rise and re-establishment of marine connections with eastern Paratethys. q 2001 Elsevier Science Ltd. All rights reserved. Keywords: Carpathian Foredeep basin; Miocene; Seismic data; Tectonics; Deposition 1. Introduction Foredeep basins belong to the broad group of sedi- mentary basins that develop due to ¯exure of the litho- spheric plates (e.g. Allen & Allen, 1990). Main features of the geological history of the foredeep basins include displacement of the zone of maximum subsidence towards the foreland of the migrating thrust belt, uplift, migration and erosion of the ¯exural forebulge and consecutive foreland-directed onlapping of the foreland plate by foredeep sediments. Typical tectonic deforma- tions encountered in the foredeep basins are related to both compressional and tensional regimes (Bradley & Kidd, 1991; Davis, Suppe, & Dahlen, 1985). Due to foreland-directed propagation of the thrust belt, older foredeep sediments become progressively involved in thrust-related folding and usually form strips of thrust and folded sediments in front of the main orogenic wedge (Gorin, Signer, & Ambereger, 1993; Ricci Lucci, 1986; Zoetemeijer, Sassi Roure, & Cloetingh, 1992). Synorogenic sediments such as conglomerates or fan-deltas that develop in front of the active thrust-related growing folds provide infor- mation on onset and particular stages of deformation within the orogenic belt (Blair & Bilodeau, 1988; Burbank, Beck, Raynolds, Hobbs, & Tahirkheli, 1988; DeCelles et al., 1987, 1991; Deville et al., 1994; Medwedeff, 1989, 1992; Pivnik, 1990; Suppe, Chou, & Hook, 1992; Williams, Ford, Verges, & Artoni, 1998). Local and regional unconformities that develop within the foredeep sedimentary in®ll are often related to the tectonic movements within the thrust belt, related various subsidence rates and fore- bulge migration (Crampton & Allen, 1995; Deramond, Souquet, Fondecave-Walles, & Specht, 1993; Flemings & Jordan, 1990; Peper, 1993; Sinclair, Coakley, Allen, & Watts, 1991). Tensional, generally thrust belt-parallel faults devel- oped within the foreland plate and related to its ¯exural Marine and Petroleum Geology 18 (2001) 13±38 0264-8172/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved. PII: S0264-8172(00)00037-4 www.elsevier.com/locate/marpetgeo * Tel.: 148-22-8495182; fax: 148-22-8495342. E-mail address: krzywiec@pgi.waw.pl (P. Krzywiec).