No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Thermal maturity of Miocene organic matter from the Carpathian Foredeep in the Czech Republic: 1D and 3D models
... This interpretation is consistent with reconstruction based on the seismic data [34], and the low thermal maturity of organic matter in the Miocene strata of the Carpathian Foredeep, which is in the range of 0.3 to 0.6%VR [37,38]. In the Czech area of the Carpathian Foredeep, even at a depth of 4300 m, thermal maturity is 0.58%VR in the Miocene sediments [39]. ...
... Model 2 assumed that 1500 m of Devonian and 1200 m of Carboniferous was eroded. This scenario was based on the geological evolution of adjacent areas [39][40][41][42]. The model showed a significant increase in VR in the Devonian to Carboniferous (Figure 6). ...
... 3) assumed important erosional events in the Jurassic (500 m) and Cretaceous (1800 m) (Figure 7). However, this model appears to be less probable considering geological evolution of the study area [39][40][41][42]. This model also allows for proper calibration. ...
Hydrocarbon exploration under thrust belts is a challenging frontier globally. In this work, 1-D thermal maturity modeling of the Paleozoic–Mesozoic basement in the northern margin of the Western Outer Carpathians was carried out to better explain the thermal history of source rocks that influenced hydrocarbon generation. The combination of Variscan burial and post-Variscan heating due to elevated heat flow may have caused significant heating in the Paleozoic basement in the pre-Middle Jurassic period. However, the most likely combined effect of Permian-Triassic burial and Late Triassic–Early Jurassic increase of heat flow caused the reaching of maximum paleotemperature. The main phase of hydrocarbon generation in Paleozoic source rocks developed in pre-Middle Jurassic times. Therefore, generated hydrocarbons from Ordovician and Silurian source rocks were lost before reservoirs and traps were formed in the Late Mesozoic. The Miocene thermal overprint due to the Carpathian overthrust probably did not significantly change the thermal maturity of organic matter in the Paleozoic–Mesozoic strata. Thus, it can be concluded that petroleum accumulations in the Late Jurassic and Cenomanian reservoirs of the foreland were charged later, mainly by source rocks occurring within the thrustbelt, i.e., Oligocene Menilite Shales. Finally, this work shows that comprehensive mineralogical and geochemical studies are an indispensable prerequisite of any petroleum system modelling because their results could influence petroleum exploration of new oil and gas fields.
... (Summary after Blizkovsky et al., 1994;Francu et al., 1994;Brzobohaty et al., 1996;Francu et al., 1996;Krejci et al., 1996;Zimmer and Wessely, 1996a;Picha and Peters, 1998;Arzmüller et al., 2006;Kostelnicek et al., 2006;Picha et al., 2006;Gerslova et al., 2015;Goldbach et al., 2017). ...
... (Summary after Blizkovsky et al., 1994;Francu et al., 1994;Brzobohaty et al., 1996;Francu et al., 1996;Krejci et al., 1996;Zimmer and Wessely, 1996a;Picha and Peters, 1998;Arzmüller et al., 2006;Kostelnicek et al., 2006;Picha et al., 2006;Gerslova et al., 2015;Goldbach et al., 2017). ...
Initial crustal collision between Africa and Eurasia in the middle Eocene – early Oligocene enclosed a semi‐restricted Paratethyan seaway of linked basins and platforms across a region stretching from the Eastern Alps to the South Caspian Sea. As the African Plate continued to advance north during the later Neogene, the seaway shrank into a series of more isolated basins separated by the rising Alpine – Carpathian – Caucasus fold‐thrust belts. Organic‐rich oil‐prone Paratethyan source rocks of middle Eocene (Kuma Formation and equivalents) and Oligocene – early Miocene (Maikop and Menilite Beds) ages, and more gas‐prone post‐orogenic mid‐upper Miocene shales, subsequently charged over 2500 accumulations across the region with combined recoverable reserves of 95 billion brl oil‐equivalent (B boe). These accumulations are clustered in discrete petroleum provinces, each with a distinct tectono‐stratigraphic architecture and comprised of one or more petroleum systems. The provinces can be grouped into five broad categories:
Average Reserves Average Field Sizes
Fold‐thrust Provinces
60,980 MMboe
2–590 MMboe
Sub‐thrust Provinces
255 MMboe
3.4 MMboe
Foreland Provinces
18,671 MMboe
2–77 MMboe
Intermontane Provinces
13,122 MMboe
1–40 MMboe
Black Sea back‐arc Province
> 1391 MMboe
>33 MMboe
The productivity of each province (estimated very approximately from the number of barrels oil equivalent / square kilometre) is extremely variable, and its relationship with the geological factors controlling hydrocarbon entrapment and retention is complex. The most critical of these factors appears to be the quality and distribution of source rocks and post‐charge structural modification.
The southernmost documented occurrences of Namurian coal-bearing strata can be found in the Němčičky area, SE Moravia, that is considered to be the southern continuation of the Upper Silesian Coal Basin. Since the south-eastern Moravia belongs to the most prospective areas in terms of hydrocarbon exploration and production in the Czech Republic and Namurian deposits are considered to be one of the potential source rocks, there was a systematic evaluation of the southernmost occurrence of coal-bearing Carboniferous deposits in the Czech Republic during the hydrocarbon exploration within the area with regard to the regional geological setting and thermal maturity. 2D and high-quality 3D seismic surveys were used for a detailed thermal maturation analysis and a determination of the regional situation of heavily faulted/eroded Namurian strata. Cores and cuttings of coal and siltstones were used from 8 boreholes to investigate and measure the vitrinite reflectance; the lithology and petrography definition was also done based on thin sections. All new measurements were compared with archived data and older studies. In the Němčičky Sub-basin, the complete sedimentary succession occurs as part of typical cyclic development, starting with basal conglomerates and followed by sandstones alternating with claystones, siltstones and coal seams of marine and transitional origin. Samples from the Nikolčice-Kurdějov ridge are showing significantly lower vitrinitte reflectance values with respect to their depths than those from the Nesvačilka graben; this fact is supporting the distinctive lateral movement along the western Nesvačilka fault as presumed from the seismic interpretation. Dominant source from “immature” orogen is combined with the source from the “mature” continetal block i.e. opposite margin of the basin. The seismic interpretation shows that the thicknesses of Namurian deposits are not decreasing at all towards the recently deeper positions; accordingly, it is suggested that it is right within this erosionally untouched accommodational space of the Němčičky Sub-basin where we can find the interconnection to the USCB in the north.
The Jurassic sedimentary succession along the eastern margin of the Bohemian Massif starts with mostly fluvial deposits of the Gresten Formation and continues after marine transgression with the deposition of the Nikolcice Formation (Middle Jurassic, Callovian). The provenance and depositional environment of the Nikolcice Formation showed that deposition occurred within offshore, transitional zone, shoreface, foreshore and littoral sand bar environments; however, shoreface and foreshore deposits dominate in the cores studied. The crystalline units along the eastern margins of the Bohemian Massif represent the primary source of deposits of the Nikolcice Formation. An important role was played by acidic and intermediate plutonites and highly metamorphosed metasedimentary rocks (granulite and amphibolite metamorphic facies), which indicates an advanced stage of erosion of the source area. The role of volcanic and intrusive rocks was small. The primary source was followed by an additional recycled source from older sedimentary rocks (especially the Moravo-Silesian Paleozoic deposits – the Liseň Formation, the Myslejovice Formation). A similarity of the source areas for the Nikolcice Formation and the underlying Gresten Formation was recognized. Identified differences in their source areas are mainly explained by varied erosional levels due to successive exhumation of the source Variscan orogen and possibly also by an expansion of the source area.
The Karpatian deposits of the central part of the Carpathian Foredeep in Moravia, which are deeply buried under the Outer Western Carpathians, provide a unique opportunity to reconstruct the former evolutionary stages of this peripheral foreland basin and its paleogeography. A succession of three depositional units characterized by a distinct depositional environment, provenance, and partly also foreland basin depozone, have been identified. The first depositional unit represents a proximal forebulge depozone and consists of lagoon-estuary and barred coastline deposits. The source from the “local” crystalline basement played here an important role. The second depositional unit consists of coastline to shallow marine deposits and is interpreted as a forebulge depozone. Tidalites recognized within this unit represent the only described tide-generated deposits of the Neogene infill of the Carpathian Foredeep basin in Moravia. The source from the basin passive margin (the Bohemian Massif) has been proved. The third depositional unit is formed by offshore deposits and represents a foredeep depozone. The provenance from both passive and active basin margin (Silesian Unit of the Western Carpathian Flysch Zone) has been proved. Thus, both a stepwise migration of the foredeep basin axis and shift of basin depozones outwards/cratonwards were documented, together with forebulge retreat. The shift of the foreland basin depozones more than 50 km cratonward can be assumed. The renewed thrusting along the basin’s active margin finally completely changed the basin shape and paleogeography. The upper part of the infill was deformed outside the prograding thrust front of flysch nappes and the flysch rocks together with a strip of Miocene sediments were superposed onto the inner part of the basin. The width and bathymetric gradient of the entire basin was changed/reduced and the deposition continued toward the platform. The basin evolution and changes in its geometry are interpreted as a consequence of the phases of the thrust-sheet stacking and sediment loading in combination with sea-level change.
Recent conodonts studies have resulted in modifications to the stratigraphical ranges of the limestones of Drahany (Basinal) and Ludmirov (Transitional) development in the Konice-Mladec Belt. The lowermost boundary of the Jesenec Limestone (Drahany development) can be shifted down to the Emsian-Eifelian boundary and the base of sedimentation of the equivalents of the Macocha Formation can be shifted to the Eifelian. The uppermost occurrence of the Jesenec Limestone reaches up to the Middle-Upper Tournaisian boundary. According to these data a considerable part of volcanic activity belongs probably to the Tournaisian. -from Authors
Petrological, sedimentological and ichnological studies of cores from the Měnín-I borehole revealed episodic shallow marine influence in the terrestrial clastics underlying the Devonian clastic and carbonate rocks. The organic-walled, acid-resistant microfossils have been recovered from bioturbated beds and have allowed us to determine the age as the earliest Cambrian (most likely Platysolenites antiquissimus Faunal Zone). Several index acritarch species justify a preliminary assignment to the Asteridium tornatum-Comasphaeridium velvetum Acritarch Zone. The microfossils are very well preserved, without any noticeable thermal alteration (thermal alteration index about 1+) or mechanical damage. The ichnoassemblage contains Diplocraterion isp., Skolithos isp., and Planolites isp. The intensity of bioturbation and ichnofabric patterns correspond well to those described from the Cambrian of the East European Platform. The composition of Cambrian acritarch assemblages, of the ichnotaxa, as well the very low thermal alteration of organic-walled microfossils, link this Moravian sedimentary cover of Brunnia (Brunovistulicum in broader sense of the meaning) to the sediments of the same age which rest on other crustal segments in the southern and central part of Poland and even further on the Baltica Paleocontinent. This indicates a connection rather than separation of these Cambrian "Gondwanan parts" and Baltica by the Trans-European Suture Zone.
The one dimensional model (1D) of thermal history and subsidence of the Sluovice-1 borehole was created in order to determine the thickness of missing units and determine temperature range reached during the Carpathian nappes thrusting. The reliability of the model was verified using vitrinite reflectance R r [%] and the stabilized temperature T [°C] measured during pumping tests as calibration parameters. The comparison of modelled and measured data (Fig. 4) provided good fit. The final 1D model represents gradual thrusting of the Miocene infill alochthone part of the Carpathian Foredeep, comprising the Soláò, Belovea and Zlín Formation on the autochthonous basement (Fig. 1) from 16.5 to 12 Ma (Picha et al. 2006). The Sluo-vice-1 borehole has specific maturation trend with depth and each individual nappe has own geothermal gradient and has to be modelled independently (Hantschel Kauerauf 2008; Guster-huber et al. 2013). The resulting thickness of the missing parts for Zlín Formation is 3 200 m, for Belovea Formation is 3 200 m, and for Soláò Formation is 4 920 m. The basal heat flow (HF) scenario during strata sedimentation (Fig. 3) respect published geological concept presented in Picha et al. (2006). Maximum modelled HF 95 mW/m 2 was achieved during Paleozoic (Fig. 3). From that time the heat flow gradually decrease to 48 mW/m 2. Following thrusting of the Carpathians nappes decreased the HF values to 40 mW/m 2. The highest temperature ranging between 110 and 115 °C was achieved in bottom part of the Paleozoic floor at the depth of 4 600 m from 12 to 11 Ma (Fig. 5).
The boreholes Gottwaldov 1 and 2(G1 and G2) are comparable boreholes drilled in exploration area of the Vizovické vrchy Hills (Fig. 1). A 1D model of subsidence and the thermal history of G1 and G2boreholes was created in order to determine the boundary conditions, heat flow, and paleowater depth (Figs 2and 3). The measured vitrinite reflectance (% Rr) and the stabilized temperature data measured during pumping tests were used as independent calibration parameters (Hantschel - Kauerauf 2009). The model input data represent geological assumptions and anticipations such as paleogeographic reconstructions, paleo-water depth development (Fig. 2), and tectonic evolution of the basin. The basal heat flow (HF) was created using McKenzie's model (1978), and taking into consideration typical HF values published by Allen and Allen (2005). HF values were decreased by 3 mW/m2 to reflect thrusting according to the model development (Gusterhuber et al. 2013). The recent HF values were ranging from 38 mW/m2 (G1) to 41 mW/m2 (G2) (Fig. 3). The resulting model represents the best fit HF scenario and two alternative HF developments. The best fit HF scenario from multi 1D approach was used to verify 2D burial history modelling (Fig. 4). The 2D cross-section modelling was calibrated using similar calibration parameters as those used in 1D modelling and confirming HF decrease from multi 1D approach. Other parameters were also tested, but not fairly confirmed. An unswered question includes in particular the impact of Jurassic rift (Pícha et al. 2006), and/or the maturity increase caused by Tertiary volcanism.
Anchimetamorphosed sandstones and conglomerates of the so-called “Basal Devonian Clastics”, that build a hill (ridge) named Babí lom, are considered to be of Lower to Middle Devonian age. Al though they are strongly tectonically affected, many sedimentary features are well-preserved and distinct. Both the facies and structures typical of alluvial fans and rivers were recognized in the sedimentary association at Babí lom. Among others, there are channel lags with imbricated grains, cross-bedding, and debrites. The way-up direc tion is clearly seen via repetitive coarsening-up wards sequences. As suming a lack of rotation of the succession in the X–Y plane, the main palaeodrainage was to wards the north and the major supply of
material was from the east. The high maturity of the rocks suggests derivation from older deposits and/or highly weathered source rocks. The magmatic rocks of the Brunovistulicum are possibly the primary source of the sediments.
This thematic issue of Annales Societatis Geologorum Poloniae contains a set of papers presenting results of a special research project entitled “Petroleum exploration prospectives and hydrocarbon potential of the
Miocene strata and Mesozoic–Palaeozoic basement in the borderland area of Poland and Ukraine”, led by research teams from the AGH University of Science and Technology in Kraków and the Polish Geological Institute – National Research Institute in Warsaw. The objective of this paper is determination of the geological and geochemical conditions, 1-D and 2-D modelling of petroleum processes and petroleum systems and their influence on the prospectives of hydrocarbon exploration of the Miocene strata in the Polish and Ukrainian Carpathian Foredeep and its Palaeozoic–Mesozoic basement. In particular, a coherent model of geological structure of the area, based both on the synthesis of the earlier published data and on new results of palynological studies of the Upper Precambrian and Lower Palaeozoic, is given. New data on microfacies of the Upper Jurassic and Lower Cretaceous strata and on sedimentology, geochemistry and micropalaeontology of the Middle Miocene rocks are presented.
Lower Devonian monomict-quartzose coarse-grained clastics near Brno (on the Červený kopec Hill) are interpreted as the deposits of an alluvial fan built up mainly by catastrophic sheetfloods. The main sources were probably granites and gneisses, other components were derived from rhyolites, older siliciclastic sediments and low-grade metamorphic rocks. Abundant presence of muscovite reflects some role of an exotic source area. Rapid uplift, crosion dominated by mechanical weathering and multiple redeposition are supposed within the drainage basin. The flat alluvial fan was only slightly reworked and eroded during subsequent non-catastrophic overland flows (secondary processes). A relatively mature stage of the evolution of the alluvial fan and drainage basin was accepted. A continental extensional basin represents the most probably depositional setting of the studied deposits.
Ab stract : T he m icrofacies of lim estone pebb les frolll th e Cu lm cong lomerates of the Draha ny Up land were cxn mi ncd ill Ihis study. The establi shed groups of m icrofacies with simi lar feat urcs have been in terpreted in terms of sed imen-tary environment and the content of fac ies of various age was analysed. For the pebb les of Upper Fam ennian-base of Mi dd le Visean limestones, the rat io of those facies wh ich are int erpre ted as calc it urbid it es, Iwmipelagites and pdag it es to the microfacies of slm llower environments rises signi fica nt ly in all Culm formations. No such facies were found in the pebbles of the Givet ian-Lower Famennian and Middle-Upper Visean limestones. Comparison of the ra ti os of the limestone pebb les of different ages in Cu lm fo rmations shows the d ec r~ase of Upper Famennian-Middle Visean mi crofacies in the direction from the older part of the Cu lm (Protivanov Fm.) to its youn ger part (Myslcjov ice Fm.). The an alyses of the micro fauna has shown tha t the pebbles of the Givetian-Lower Famenn ian and Mi ddlc-U pp!.!r Visean limestones occur in the east em part of the Drahany Up land onl y. Th ese trends in the content of the limestone pebb les of various ages and sediment ary environments in indiv idual fo rm ations and thei r area l distribut ion are interpreted as a resu lt of two processes: I) progressive eros ion of the sed imen tary cover of the basement uni t from its distal (pelagic and hemipelagic) th rough prox im al (platform) parts due 10 foreward thrust propagati on in th e accretionary wedge of the co lli ding terranes; 2) post-sedi mentary tecton ic juxtapositi on of the western and the eastem parts of th e Drahany Culm. An advantage of the microfacial analysis of lim estone pebbles is demonstrated for the regions where source-rocks were tecton ica ll y modified aft er their erosion and/or where the source-area was covered wit h younge r sedi ment s.
There are close similarities between the Brunovistulian Terrane and the Istanbul Zone both in the Neoproterozoic and Paleozoic. The geological structure, lithology and geochronology of the Cadomian Brunovistulicum show broad fit with the crystalline basement of the Istanbul Zone. Their Gondwana or Baltica affinity is still poorly constrained and remains a matter of discussion. The Vendian and Cambrian sequences recognized in the central Małopolska, Brunovistulian and Moesian terranes correlate well with the Scythian Platform. In the Istanbul Zone the presence of the pre-Ordovician sedimentary sequences has not been confirmed and may only be anticipated. In the Paleozoic the best fit was attained in the Devonian-Carboniferous interval. The sedimentary record in the Zonguldak and Istanbul Terranes closely compares to the Moravian Karst and Ludmirov facies developments of the Brunovistulian Terrane. The correlation is reinforced by a good fit of the main Variscan deformation phases attributed both in the Brunovistulian Terrane and the Istanbul Zone to the late Visean-early Namurian and Westphalian-Stephanian intervals. This supports, together with the paleobiogeographic data, the interpretation that the Istanbul and Zonguldak Terranes can be regarded as counterparts of the Rhenohercynian and Subvariscan Zone in Central Europe. The Istanbul Zone is juxtaposed against the Sakarya Zone viewed as a part of the American Terrane Assemblage.
This paper illustrates the application of multidisciplinary data analysis to the Carpathian-Pannonian Region and on the basis of geodetical data presents verification of a tectonic model of the Carpathian-Pannonian lithosphere with impact on the possible risk and activity of the geodynamic and kinematical zones in consequence of the post-subduction processes. This approach and analyses can be used for the analyses any Carpathian area from the point of view of the recent movements tendencies.
All available mentioned geodata were verified and unified on the basis of the same scale and in the Western Carpathians on the remote sensing data, too.
Independent GPS epoch-wise observing campaigns took place in several regions and the whole territory is now covered by tens of permanent stations. The long-term observational series from permanent stations generally yield reliable site velocities, however, distribution of such stations is not dense enough to provide velocity field with sufficient resolution all over the monitored region.
In the paper we also shortly describe velocity fields available from various national and regional GPS geo-kinematics projects. The heterogeneous velocity fields have been homogenized and used for construction of the intraplate GPS velocities in Central and South-East Europe and their interpretation, focusing on the chosen active zone. As one of most important we consider — so called — “rebounding area” in East Carpathians. The proposed interpretation and solution enable to consider new view on the Pliocene to recent period.
On the basis of extrapolation of failure criteria, lithology, and temperature models, we predict the rheology of the lithosphere for several sections through the Carpathians and surrounding regions. Our models show significant lateral variations in rheology for the different tectonic units, with important implications for the tectonic evolution. The rheologically strong lithosphere of the Polish Platform area contrasts with the weak lithosphere of the Pannonian basin, indicating that the arcuate shape of the Carpathian orogen is primarily caused by an inherited curvature of an ancient embayment in the foreland, with the Pannonian units passively filling the space. The Polish Platform and the Moesian Platform exhibit a similar rheological anisotropy caused by NW-SE trending weakness zones paralleling the Tornquist-Teisseyre zone. This anisotropy was the main controlling factor on the behavior of the lithosphere in this area since Cadomian times, as documented by the geological evolution of the Sudety Mountains and the Mesozoic Polish Trough, including the Late Cretaceous Alpine inversion and the Neogene development of the Carpathian foreland. This rheological anisotropy appears to have a major controlling impact on the development of at least the eastern part of the European lithosphere. Rheology predictions for the Bohemian massif support the idea that the rigid lithosphere of the Bohemian massif governed the bending of the Alpine-Carpathian transition zone, expressed in the large-scale wrench movements opening the Vienna basin. In the foreland area, detachment levels are predicted for upper and lower crustal levels, leading to a decoupling of crustal and subcrustal flexure in most areas. Comparison with basin formation models indicates that our predictions for effective elastic thickness (EET) are similar to those derived from flexural models for the foreland area. Also, EET predictions from extensional basin models in the Pannonian region yield values close to our findings.
Scaled sandbox models based on field and seismic data were used to simulate Miocene evolution of the Carpathian orogenic front. The experiments investigated the influence of synorogenic deposition on the geometry and kinematics of growing tectonic structures. The deposition introduced at the foreland of an active fold-thrust wedge resting on top of a weak ductile detachment horizon generally results in transferring the deformation to the rear part of the model. Depending on the rate and across-strike extent of synorogenic sedimentation and on the moment it starts, a single major back thrust above the rear edge of the ductile layer can form or out-of-sequence foreland verging thrusts can be initiated. Alternatively, older thrust faults can be reactivated at the rear part of the model thrust wedge, leading to destruction of the earlier formed structures. Our experiments explain the origin and evolution of three different structural geometries known from the Carpathian orogenic front, involving major back thrusts related to triangle zones and out-of-sequence breaching forethrusts that substantially reorganized deformation patterns in a growing thrust wedge. The development of these geometries was controlled by massive synorogenic sedimentation in the foreland. From the modeling and natural examples we infer a number of typical structural situations that can occur at an orogenic front underlain by a weak ductile horizon, depending on parameters controlling synorogenic sedimentation and tectonic push exerted by an approaching thrust wedge.
The Brunovistulian terrane represents a microcontinent of enigmatic Proterozoic provenance that was located at the southern
margin of Baltica in the early Paleozoic. During the Variscan orogeny, it represented the lower plate at the southern margin
of Laurussia, involved in the collision with the Armorican terrane assemblage. In this respect, it resembles the Avalonian
terrane in the west and the Istanbul Zone in the east. There is a growing evidence about the presence of a Devonian back-arc
at the margin of the Brunovistulian terrane. The early Variscan phase was characterized by the formation of Devonian extensional
basins with the within-plate volcanic activity and formation of narrow segments of oceanic crust. The oldest Viséan flysch
of the Rheic/Rhenohercynian remnant basin (Protivanov, Andelska Hora and Horní Benesov formations) forms the highest allochthonous
units and contains, together with slices of Silurian Bohemian facies, clastic micas from early Paleozoic crystalline rocks
that are presumably derived from terranes of Armorican affinity although provenance from an active Brunovistulian margin cannot
be fully excluded either. The development of the Moravo–Silesian late Paleozoic basin was terminated by coal-bearing paralic
and limnic sediments. The progressive Carboniferous stacking of nappes and their impingement on the Laurussian foreland led
to crustal thickening and shortening and a number of distinct deformational and folding events. The postorogenic extension
led to the formation of the terminal Carboniferous-early Permian Boskovice Graben located in the eastern part of the Brunovistulian
terrane, in front of the crystalline nappes. The highest, allochthonous westernmost flysch units, locally with the basal slices
of the Devonian and Silurian rocks thrusted over the Silesicum in the NW part of the Brunovistulian terrane, may share a similar
tectonic position with the Giessen–Harz nappes. The Silesicum represents the outermost margin of the Brunovistulian terrane
with many features in common with the Northern Phyllite Zone at the Avalonia–Armorica interface in Germany.
Organic and clay indicators were measured to characterise the burial and thermal history of Devo-nian through Upper Carboniferous siliciclastic and carbonate rocks in the Rheno-Hercynian zone of the Variscan orogeny in Moravia (eastern Czech Republic). The very low-grade metamorphism is documented by the illite crystallinity (IC) and vitrinite reflectance (R r) in the inner part of the thrust and fold belt in the NNW. Application of forward thermal modelling suggests maximum palaeo-temperature of 240–360 • C and burial depth of 4–9 km. In the Variscan foreland in the SSE the IC and R r values are typical of diagenetic conditions with maximum palaeo-temperature of 80–130 • C. The distribution of both clay and organic maturity parameters is interpreted as a result of pre-and syn-tectonic thermal exposure of the rocks due to burial by a wedge-shaped body of thrust sheets thinning towards the Variscan foreland where only sedimentary burial was effective. The amount of uplift and denudation increases from the foreland to the Rheno-Hercynian thinskinned thrust and fold belt.
During the Tertiary orogeny, the Carpathian Flysch Belt was thrust over the southeastern margin of the Epivariscan North European Platform in southern Moravia. Based on geological and geophysical data the autochthonous lithostratigraphic units in the region may be divided into several tectonic blocks with different geological history and regional extent. Oil and gas source rocks occur in the Devonian to Lower Carboniferous carbonate sediments and are abundant in the autochthonous Upper Jurassic marlstones and Paleogene sediments. During the Savic and Styrian phases of the Alpine orogeny, the overthrust flysch nappes have buried the autochthonous lithostratigraphic units to depths favourable to hydrocarbon generation. -Authors
Tectonic evolution of the SE part of the North European Platform and its contact with the West Carpathians in Moravia (Czech Republic), where the present Variscan and Alpine orogens with opposite vergencies are overlapping, is reconstructed from seismic profiles and deep borehole sections and simulated with basin modeling software (1-D PDI-PC™, IES). The conceptual model is based on a series of stratigraphic and tectonic events (i.e., deposition, erosion, non-deposition, and thrusting) in this area. Some of the depositional and erosional events are inferred, and their extent is estimated based on organic maturity data.
Regional kinematic analysis of the more internal domains prove the early-Variscan top-to-N lower crust synmetamorphic nappe shearing. The Lower Devonian collision caused ENE-WSW transtensional stretching - oblique rifting of the Brunovistulian foreland brittle crust. The top-to-N thrusting of the Variscan orogenic front is recorded by an a-type of stretching lineations in the gneiss of the Orlice-Sneznik Unit. Due to the NW-SE trend of the western indented edge of the Brunovistulian foreland, an oblique dextral wrench collision in the Moravosilesian Zone occurred. The late-Variscan transtension, with an ENE trend of stretching lineations, followed crust overthickening. The gravitational collapse and out-ward lateral escape in the inner and deeper domains was contemporaneous with wide-spread intrusions of S-type granites and the growing of subperpendicular half-grabens. -from Authors
The thermal maturity of Paleozoic rocks in the SE part of the Bohemian Massif is characterized by clay minerals and organic matter. The expandability of illite-smectite (S in I-S), illite crystallinity index (IC) and reflectance of (R(r)) were measured and their regional distribution was evaluated. The mutual correlation of IC and R(r) from diagenesis to very low-grade metamorphism is compared with the published data and used to distinguish data with more reliable paleogeothermal information from those affected by other factors. In the SE part the Paleozoic units have illite-smectites with an expandable component of 15-35 % S. The reflectance values (R(r) of 0.55-1.1 %) are in good agreement with the expandability and suggest the oil window range of catagenesis with paleotemperature close to 100 °C. In the NNW part of the area the clays contain no expandable layers in illite. The illite crystallinity (IC of 0.36-0.24 Δ °2Θ) and vitrinite reflectance (R(r) from 3.17 to 5.23 %) indicate very low-grade metamorphic conditions with probable maximum paleotemperatures of 240-300 °C. The systematic change in both clay and organic parameters shows the gradual decrease in thermal exposure towards the front of the Variscan orogenic zone in the S and SE and suggest extensive erosion in the NNW.
According to geomorphologic, seismic and gravimetric analyses carried out in the area between Frenštát pod Radhoštěm and Vsetín, today, the mountain regions of Kněhyně and their wider neighbourhood are not in balance with the platform basement and the processes of erosion. This is caused by the fact that, due to the accumulation of light masses of Lower Miocene rocks of the Carpathian Foredeep in footwall of the Godula nappe and frontal parts of the Magura nappe, mountain peaks arrived to higher altitudes than one would expect from simple overthrusting of the Silesian and Subsilesian units over the underlying foreland. Consequently, the whole mountain massifs experience gravitational spreading and break-up, which is well documented by development of deep and widespread deformations - predomininantly by pseudokarst phenomena. Concept of gravitational break-up of whole mountain complexes by mechanism of gravitational spreading is presented. The mechanism of gravitational spreading may in specific instances generate gravitational nappes but, for the most part, it is effective on continental slopes of the present-day oceans. More recently, however, the gravitational spreading is often considered in explanations of extension of mountain regions during final stages of orogenic cycles when the tectonic uplift exceeds topographic reduction due to denudation and erosion, which is the case of the Western Carpathians flysch.
In the Magura Group of nappes, Cretaceous sediments were proved in the Rača and Bílé Karpaty units nearly in the whole range of the period. This was made possible by new biostratigraphic (foraminifers and calcareous nannofossils) and biofacies data. In the present paper, the Kurovice Klippe, Gault Flysch, Kaumberg Formation and the lower part of the Sólaň Formation are included in the Rača Unit, while the Hluk, Kaumberg and Javorina formations and the lowermost part of the Svodnice Formation are placed in the Bílé Karpaty Unit. Some lithostratigraphic units of Senonian age appear in tectonic slices only (Púchov Marl and Antonínek Formation) which makes their incorporation into the paleogeographical model of the Magura Group of nappes difficult.
Biomarker analyses indicate that at least two petroleum systems operate in the Vienna basin, Carpathian thrust belt and the European foreland plate in Moravia - one associated with Jurassic and the other with Palaeogene organic-rich rocks. Four oils from the sub-Carpathian foreland plate and one sample from the Vienna basin were analysed and geochemically compared to extracts from Jurassic and Palaeogene source rocks. Two oils from the subthrust foreland plate (Lubna-18 and Dolni Lomna-1) are genetically related based on similar geochemical compositions. These oils show high oleanane and 24-nordiacholestane ratios, age-related biomarker ratios that are consistent with an origin from Palaeogene organic-rich rocks. These rocks are inferred to be either the Menilitic shales of the Carpathian thrust belt or autochthonous Palaeogene deposits buried below the thrust belt. Two other oils from the subthrust plate (Zdanice-7 and Damborice-16) correlate geochemically with extracts from Jurassic source rocks in the Sedlec-1 and Nemcicky-1 wells. Like the oil extracts, these oils lack oleanane and show low 24-nordiacholestane ratios, supporting an origin from Jurassic organic-rich marls. The oil sample from the Vienna basin (Tynec-34) appears to be a mixture of the two oil groups.
Sedimentary basins in NW-Germany and the Netherlands represent potential targets for shale gas exploration in Europe due to the presence of Cretaceous (Wealden) and Jurassic (Posidonia) marlstones/shales as well as various Carboniferous black shales. In order to assess the regional shale gas prospectivity of this area a 3D high resolution petroleum system model has been compiled and used to reconstruct the source rock maturation based on calibrated burial and thermal histories. Different basal heat flow scenarios and accordingly different high-resolution scenarios of erosional amount distribution were constructed, incorporating all major uplift events that affected the study area. The model delivers an independent 3D reappraisal of the tectonic and thermal history that controlled the differential geodynamic evolution and provides a high-resolution image of the maturity distribution and evolution throughout the study area and the different basins. Pressure, temperature and TOC-dependent gas storage capacity and gas contents of the Posidonia Shale and Wealden were calculated based on experimentally derived Langmuir sorption parameters and newly compiled source rock thickness maps indicating shale gas potential of the Lower Saxony Basin, southern Gifhorn Trough and West Netherlands Basin.This article is protected by copyright. All rights reserved.
The results of seismic measurements along three deep seismic sounding (DSS) profiles on the territory of Czechoslovakia and in adjacent countries have provided sufficient material about the crustal structure and the depth of the Moho discontinuity. These data, together with gravity and aeromagnetic data and the determinations of heat-flow values, were used to select several locations where the temperature—depth profiles were calculated. The Moho temperature of about 500 C beneath the Bohemian Massif increases to 800–1000 C and even more beneath the inner Neogene depressions of the Carpathian system. The regional differences in mantle heat-flow contribution between both these provinces may reach 1 μcal. cm−2 sec−1; such a variation in energy inflow may then be the driving force for the geological evolution. The geophysical implications of different thermal structure of the crust are discussed. Because of high subsurface temperatures in the Hungarian basin, partial melting at a depth of about 30 km may not be excluded.
This paper presents a model of depositional history in the Karpatian stage, Lower Miocene of the Carpathian Foredeep based on the study of foraminifers. The paleoecological interpretations, and the data on bioevents and biofacies of the Karpatian deposits were obtained through the statistical evaluation of microfauna. The occurrence of rich faunas alternating with impoverished ones indicates unstable conditions in the depositional area. Euryoxybiont foraminifers such as Bolivina div. sp., Bulimina div. sp., Praeglobobulimina div. sp., and Uvigerina div. sp. dominate these faunas. Two biostratigraphical levels containing Uvigerina and an overlying one with Pappina breviformis (Papp and Turn.) were identified. Two stages of the development of a transgression can be distinguished. The first stage spread to the eastern part of the Carpathian Foredeep, where the sediments contain agglutinated foraminifers. The second stage reached the present location of the Karpatian deposits. Later shallow-water sediments in the western part of the Carpathian Foredeep have been eroded away.
SUMMARY The coalification data (vitrinite reflectance, percentage Rm) from 49 boreholes located in the Czechoslovak part of the Upper Silesian Basin were processed and the palaeotemperature gradient which prevailed during the Namurian and the Early Westphalian was estimated. Very high gradients (mean: 95 Km-1) are calculated at least in the western part of the basin during the Namurian A. At that time, the Ostrava Formation (FM) was deposited with a high subsidence rate. The corresponding heat flow density of 200 mW m-2 may not reflect the characteristic heat flow density of the region, but may represent a subsurface value within the uppermost 2–3 km thick layer, probably sustained by the convective system inside the basin. The gradient during the Namurian B, C and Westphalian A is lower (mean: 77 K km-1 in the Karviná FM). It is suggested that the decrease in the gradient coincides with changes in the basin development. An intra Namurian hiatus occurred at the turn of the Namurian A and B. The lower thermal regime which governed during the sedimentation of the Karviná FM, results also from the Rm data of the Ostrava FM at the southern rim and in the Karviná part of the basin (mean gradient 60–65 K km-1). Due to the relatively small thickness of the Ostrava FM and/or the big thickness of the Karviná FM in these areas, the sediments of the Ostrava FM reached the maximum temperature during the deposition of the Karviná FM. Thus, the Rm data must reflect the lower gradient. By applying palaeogradients estimated in both formations together with present mean thermal conductivities within them, a heat flow density of 115–130 mWm-2 was computed. This value agrees well with the heat flow of 125 mWm-2 estimated for the Westphalian A in the Ruhr Basin by the same method.
Selected representative core and gas samples from the Miocene sediments of the Polish part of the Carpathian Foredeep were analyzed by means of geochemical methods. The results of elementary analyses, vitrinite reflectance and δ13C-values of organic matter, as well as the Rock-Eval® data and distribution of n-alkanes and isoprenoids, have shown that the organic matter is mainly of type III (terrestrial origin) and presents a feeble degree of maturation (beginning of oil window at 2000–3000-m depth interval, according to vitrinite reflectance). According to °13C-values, however, methane in these series results from biogenic processes.
The Lower Saxony Basin (LSB) in northwest Germany is one of the oldest oil‐producing basins in the world, where the first production well was drilled in 1864. It has been intensively investigated with respect to its hydrocarbon potential and can be regarded as a well‐studied example of a sedimentary basin that experienced strong inversion and uplift. Oil and gas source rocks of economic importance include Upper Carboniferous coals as well as Jurassic (Toarcian Posidonia Shale) and Cretaceous (Berriasian/Wealden) shales. We have developed a fully integrated 3D high‐resolution numerical petroleum systems model incorporating the LSB, and parts of the Pompeckj Block in the north as well as the Münsterland Basin in the south. Aside from temperature and maturity modeling calibrated by a large amount of vitrinite reflectance and downhole temperature data, we also investigated petroleum generation and accumulation with special emphasis on the shale gas potential of the Jurassic Posidonia Shale.
The Brno Massif in Moravia, Czech Republic, is an important exposure of Precambrian basement in central Europe. It includes
large volumes of Cadomian granitoids and a narrow fault-bounded zone with metagabbros, metadiorites, and metabasalts. This
so-called Central Basic Belt also contains some metarhyolites; one of these was dated by means of the zircon evaporation method
at 725 ±15 Ma. Chemical and isotope data show that the dated rock represents a mantle-derived magma which is cosanguinous
with surrounding MORB-type metabasites. The data suggest that the Brno Massif hosts the oldest metabasite complex currently
known in central Europe. Its formation apparently coincides with the main period of ocean-floor spreading and island-arc formation
in the Panafrican orogens. This lends further support to the theory that the Brno Massif is a Gondwana-derived element.
We have modelled three-dimensional seismic anisotropy of the mantle lithosphere from anisotropic parameters of teleseismic body waves. We invert jointly shear-wave splitting parameters and P residual spheres based on data from dense networks of temporary and permanent stations in four European regions ranging from the Variscan belt to the Baltic Shield. Changes in orientation of the large-scale anisotropy, caused by systematic preferred orientation of olivine, identify boundaries of domains of mantle lithosphere. Individual domains are characterized by a consistent large-scale orientation of anisotropy approximated by hexagonal or orthorhombic symmetry with generally inclined symmetry axes. The domains are separated by mapped tectonic boundaries (sutures), which cut the entire lithosphere. Besides the change of anisotropy orientation at domain boundaries, we often observe a change of the lithosphere and/or crust thicknesses. We do not detect any fabric of the mantle lithosphere, which could have been produced by a collision of microcontinents in a volume detectable by large-scale seismic anisotropy. The observations of consistent anisotropy within individual blocks of the mantle lithosphere reflect frozen-in olivine preferred orientation, most probably formed prior to the assembly of microcontinents that created the modern European landmass. Therefore, our findings support a plate tectonic view of the continental lithosphere as a mosaic of rigid blocks of the mantle lithosphere with complicated but relatively sharp contact zones. These contacts are blurred by the easily deformed overlying crust terranes.
The karpatian in the carpathian foredeep (Moravia) The Karpatian
- J Ad Amek
- R Brzobohatý
- P Sikula
- J Brzobohatý
- R Cicha
Ad amek, J., Brzobohatý, R., P alenský, P.,
Sikula, J., 2003. The karpatian in the carpathian foredeep (Moravia). In: Brzobohatý, R., Cicha, I., Kov a c, M., R€ ogl, F.
(Eds.), The Karpatian, a Lower Miocene Stage of the Central Paratethys. Masaryk
University, Brno, pp. 75e92.
The jurassic floor of the bohemian massif in Moravia e geology and paleogeography
- Z Ad Amek
Ad amek, Z., 2005. The jurassic floor of the bohemian massif in Moravia e geology
and paleogeography. Bull. Geoscience 80 (4), 291e305.
The carpathian foredeep
- R Brzobohatý
- I Cicha
Brzobohatý, R., Cicha, I., 1993. The carpathian foredeep. In: P richystal, A.,
Obstov a, V., Suk, M. (Eds.), The Geology of the Moravia and Silesia, vol. 1. MZM a
P rF MU, Brno, pp. 123e128 (in Czech).
The Moravian foredeep and its hydrocarbon potential. ESRI Occasional Publication 11A
- J T Dorman
Dorman, J.T., 1995. The Moravian foredeep and its hydrocarbon potential. ESRI
Occasional Publication 11A, pp. 89e116. Slovakian Geol. Korab Meml. Volume. 1.
Variský fly sový vývoj v Nízk em Jeseníku na Morav e a ve Slezsku
- J Dvo R Ak
Dvo r ak, J., 1994. Variský fly sový vývoj v Nízk em Jeseníku na Morav e a ve Slezsku.
Pr ace
Ces. Geol. Úst 3, 80 (in czech).
Facies and paleogeography of the jurassic of the bohemian massif
- M Eli A S
Eli a s, M., 1981. Facies and paleogeography of the jurassic of the bohemian massif.
Sbor. Geol. V ed Geol. 35, 75e144.
- E Franc U
- J Franc U
- Z Boh A Cek
Franc u, E., Franc u, J., Boh a cek, Z., P alenský, P., 1999b. Diagenetic trends in the carpathian foredeep, Moravia. Geol. Carpathica. 50, 23.
Geodynamic model of the contact aera of the bohemian massif and western Carpathians
- O Krej Cí
- J Franc U
- F Hubatka
- J Mrlina
- J Sedl Ak
Krej cí, O., Franc u, J., Hubatka, F., Mrlina, J., Sedl ak, J., 2001. Geodynamic model of the
contact aera of the bohemian massif and western Carpathians. Slovak Geol.
Mag. 1, 163e164.
Nov e pohledy na vývoj karpatu pod fly sovými p ríkrovy v úseku
- H Thonov A
- M Holzknecht
- I Krystek
- R Brzobohatý
Thonov a, H., Holzknecht, M., Krystek, I., Brzobohatý, R., 1987. Nov e pohledy na vývoj
karpatu pod fly sovými p ríkrovy v úseku "St red". Zemní Plyn. Nafta 32 (3),
383e389.
The jurassic floor of the bohemian massif in Moravia e geology and paleogeography
- J Ad Amek
- R Brzobohatý
- P Sikula
- J Brzobohatý
- R Cicha
Ad amek, J., Brzobohatý, R., P alenský, P.,
Sikula, J., 2003. The karpatian in the carpathian foredeep (Moravia). In: Brzobohatý, R., Cicha, I., Kov a c, M., R€ ogl, F.
(Eds.), The Karpatian, a Lower Miocene Stage of the Central Paratethys. Masaryk
University, Brno, pp. 75e92.
Ad amek, Z., 2005. The jurassic floor of the bohemian massif in Moravia e geology
and paleogeography. Bull. Geoscience 80 (4), 291e305.
Temperature-depth profiles in Czechoslovakia and some adjacent areas derived from heat-flow measurements, deep seismic sounding and other geophysical data. Tectonophysics 26, 103e119. Cerm ak
- V Cerm Ak
- M Dopita
- J Aust
- J Brieda
- I Cerný
- P Dvo R Ak
- V Fialov A
- J Foldyna
- A Grmela
Cerm ak, V., 1975. Temperature-depth profiles in Czechoslovakia and some adjacent
areas derived from heat-flow measurements, deep seismic sounding and other
geophysical data. Tectonophysics 26, 103e119.
Cerm ak, V., 1977. Heat flow map of the bohemian massif. J. Geophys 42, 455.
Dopita, M., Aust, J., Brieda, J.,
Cerný, I., Dvo r ak, P., Fialov a, V., Foldyna, J., Grmela, A.,
Shallow Reflection Seismic Prospecting of the Kurovice Klippe (Magura Flysh) and its Structural Interpretation. Geolines. 8, 42. Institute of Geology
- R Grygar
- M Vavro
- F Hubatka
- J Hru Ska
- O Krej Cí
- Z Str Aník
- L Sv Abenick A
- V Valtr
Grygar, R., Vavro, M., 1995. Evolution of lugosilesian orocline (North-Western periphery of the bohemian massif): kinematics of variscan deformation.
Cas.
Mineral. Geol. 40, 65e90.
Hubatka, F., Hru ska, J., Krej cí, O., Str aník, Z.,
Sv abenick a, L., Valtr, V., 1999. Shallow
Reflection Seismic Prospecting of the Kurovice Klippe (Magura Flysh) and its
Structural Interpretation. Geolines. 8, 42. Institute of Geology, Academy of
Sciences of the Czech Republic, Praha.
- G H Taylor
- M Teichmüller
- A Davis
- C F K Diessel
- R Littke
- P Robert
Taylor, G.H., Teichmüller, M., Davis, A., Diessel, C.F.K., Littke, R., Robert, P., 1998.
Organic Petrology. Gebrüder Borntraeger, Berlin.