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.

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This study presents a synthesis of currently available data on the distribution of Cenomanian-age palaeodrainage systems in the Bohemian Cretaceous Basin, filled by fluvial and estuarine strata, and an interpretation of their relationships to the basement units and fault systems. Much of the progress, compared to previous studies, was made possible by a recent basin-scale evaluation of Cenomanian genetic sequence stratigraphy. Several local palaeodrainage systems developed in the basin, separated by drainage divides of local importance and one major divide -the Holice-Nové Město Palaeohigh -which separated the drainage basins of the Tethyan and Boreal palaeogeographic realms. The locations and directions of palaeovalleys were strongly controlled by the positions of inherited Variscan basement fault zones, whereas the bedrock lithology had the subordinate effect of narrowing or broadening valleys on more vs. less resistant substratum, respectively. The intrabasinal part of the palaeodrainage network followed the slopes toward the Labe (Elbe) System faults and was strongly dominated by the conjugate, NNE-trending, Jizera System faults and fractures. Outlet streams -ultimate trunk streams that drained the basin area -are interpreted to have followed the Lužice Fault Zone toward the Boreal province to the Northwest, and the Železné hory Fault Zone toward the Tethyan province to the Southeast. At both the northwestern and southeastern ends of the Bohemian Cretaceous Basin, shallow-marine or estuarine conditions are proven to have existed during the early Cenomanian. Direct evidence for syn-depositional subsidence during the early to mid-Cenomanian, fluvial to estuarine phase is very rare, and the onset of deposition by fluvial backfilling of the palaeodrainage systems was driven mainly by the long-term rise in global sea level. Subtle surface warping, mostly without detectable discrete faulting, is inferred to have been a response to the onset of the palaeostress regime that later, with further stress accumulation, led to subsidence in fault-bounded depocentres of the Bohemian Cretaceous Basin and uplift of new source areas. •

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Abstract:The Upper Silesian Coal Basin (USCB) represents a typical foreland basin developed during the Variscan orogenic phase of the Late Carboniferous. Later, during the Alpine orogeny the Outer Western Carpathian nappes were thrust over the post-Variscan foreland, to which the USCB belongs. Due to this complex tectonic history, redistribution of stress fields occurred in the post-Variscan basement. Furthermore, post-Variscan denudation processes probably also contributed to recent stress regimes. Nevertheless, the impact of the West Carpathian orogeny can be regarded as the most significant influence. The in-situ measurement of recent stress fields in deposits of the Karviná Formation of the USCB and structural analysis of the Czech part of the USCB, has focused on verification of the structure and stress interference of the Carpathian nappes and post-Variscan foreland basement. In the southernmost part of the Karviná Subbasin, the easternmost domain of the USCB, situated in the apical zone of the Variscan accretionary wedge, hydrofracturing and overcoring stress measurements have been recorded in coal seams from selected coal mines. The data have been supplemented by interpretation of focal mechanism solutions of mine induced seismic events. Measurements of recent in-situ stress regimes in the Karviná Formation of the USCB indicate a dominant generally NW-SE orientation of the maximum horizontal compression stress. The results demonstrate that the stress-strain regime in the Karviná Formation in the Variscan Upper Carboniferous basement is significantly influenced by the stress field along the Outer Western Carpathian nappes front. Besides improving our understanding of recent regional stress fields within an area of mutual structural-tectonic interference by both the Variscan and Alpine orogenies, the measured data may contribute to more optimal and safer mining activities in the coal basin.