Evolution of basin architecture in an incipient continental rift: the Cenozoic Most Basin, Eger Graben (Central Europe)

Abstract

The Oligo -Miocene Most Basin is the largest preserved sedimentary basin within the Eger Graben, the easternmost part of the European Cenozoic Rift System (ECRIS).The basin is interpreted as a part of an incipient rift system that underwent two distinct phases of extension.The ¢rst phase, characterised by NNE^SSW-to N^S-oriented horizontal extension between the end of Eocene and early Miocene, was oblique to the rift axis and caused evolution of a fault system characterised by en-e¤ chelon-arranged E^W (ENE^WSW) faults.These faults de¢ned a number of small, shallow initial depocentres of very small subsidence rates that gradually merged during the growth and linkage of the normal fault segments.The youngest part of the basin ¢ll indicates accelerated subsidence caused probably by the concentration of displacement at several major bounding faults. Major postdepositional faulting and forced folding were related to a change in the extension vector to an orthogonal position with respect to the rift axis and overprinting of the E^W faults by an NE^SW normal fault system.The origin of the palaeostress ¢eld of the earlier, oblique, extensional phase remains controversial and can be attributed either to the e¡ects of the Alpine lithospheric root or (perhaps more likely because of the dominant volcanism at the onset of Eger Graben formation) to doming due to thermal perturbation of the lithosphere.The later, orthogonal, extensional phase is explained by stretching along the crest of a growing regional-scale anticlinal feature, which supports the recent hypothesis of lithospheric folding in the Alpine^Carpathian foreland.

Regional chemostratigraphic key horizons in the macrofossil-barren siliciclastic lower Miocene lacustrine sediments (Most Basin, Eger Graben, Czech Republic)

“…The Most Basin is a part of the European Cenozoic Rift System (Kopecký 1978, Ziegler & Dèzes 2007, Rajchl et al 2009). In the past century its study has mainly been motivated by coal mining (Pešek et al 2010 and references therein) and later also by search for clay sources (Rákosová 1982, Sloupská 1985.…”

“…Apparent lack of correlation horizons in the Most Basin fill and doubts about isochronicity of the coal formation (Hokr 1982, Elznic et al 1998 have hindered correlation of previous formal lithostratigraphic schemes for the different parts of the basin. Recent research in the Most Basin has included palaeobotany with environmental interpretations (Kvaček 1998, Kvaček et al 2004, Teodoridis & Kvaček 2006, Teodoridis 2010, Teodoridis et al 2011, sedimentology of fluvial and fluviodeltaic systems (Rajchl & Uličný 2005, Rajchl et al 2008) and basin development (Rajchl et al 2009), correlation of the main coal seam by geophysical logs (Mach 1997) and analysis of sulphur stable isotopes . A missing local stratigraphic frame for these studies is hence an obstacle, which hinders integration of that research and its palaeonvironmental interpretation.…”

Compaction of lignite: a review of methods and results

“…Such a situation has been observed in some parts of the North Bohemian Basin (e.g. Hurník 1972;Rajchl and Uličný 2005;Rajchl et al 2009). The mire surface prior to burial was almost horizontal, in contrast to the tilted top of the present-day lignite seam.…”

“…Van Hinte 1978;Miall 1981;Doglioni and Goldhammer 1988;Allen and Allen 1990; Ten Veen and Kleinspehn 2000; Michon et al 2003;Volkov 2003;Rajchl and Uličný 2005;Widera et al 2008;Rajchl et al 2009;Widera and Hałuszczak 2011). Such processes are relatively well-known and accepted in the case of mineral deposits (Baldwin and Butler 1985;Sheldon and Retallack 2001).…”

“…Collinson and Scott 1987;Kojima et al 1998), 'consolidation coefficient' (Widera 2002;Widera et al 2007), or 'compaction ratio' (e.g. Ting 1977Ryer and Langer 1980;DeMaris et al 1983;Law et al 1983;McCabe 1984McCabe , 1987Elliot 1985;White 1986;Winston 1986;Courel 1987;Salinas et al 1990;Gayer and Pešek 1992;Nadon, 1998;Greb et al 2003;Petersen et al 2003;Rajchl and Uličný 2005;Rajchl et al 2009;Jerrett et al 2011;Flores 2013). As the most common, the term 'compaction ratio' will therefore be employed throughout this paper, particularly in the final sections.…”