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Zarys budowy i ewolucji tektonicznej waryscyjskiej struktury Sudetów

Mazur S., Aleksandrowski P., Szczepiński J.

Przegląd Geologiczny

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2010

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Vol. 58, nr 2

133-145

EN

The structure and evolution of the Polish part of the Sudetes is reviewed on the basis of published data and interpretations. The Sudetic segment of the Variscides and its adjacent areas were subjected to multi-stage accretion during successive collisional events that followed closure of different segments of the Rheic Ocean. Early Variscan deformations culminated in the Late Devonian due to docking of the Armorican terrane assemblage to the southern margin of Laurussia. The Variscan orogenic activity continued into the Carboniferous and was associated with a new collision and intense folding and thrusting, followed by abundant magmatism, gravitational collapse and resulting exhumation of deeply buried metamorphic complexes as well as by inversion of the foreland basin. In the Sudetes, Variscan tectonostratigraphic units are tectonically juxtaposed and often bear record of contrasting exhumation/cooling paths, constrained by palaeontological and geochronological data. This provides evidence for the presence of allochthonous units, of partly cryptic tectonic sutures and an of overall collage-type tectonics of that area. The main lithostratigraphical components distinguished within the Sudetes are: 1) non-metamorphic to metamorphosed Neoproterozoic igneous suites accompanied by volcano-sedimentary successions, 2) Late Cambrian granitoids gneissified during the Variscan orogeny, 3) variously metamorphosed Ordovician through Devonian volcano-sedimentary successions deposited in pre-orogenic extensional basins, 4) dismembered fragments of a Late Silurian ophiolitic complex, 5) Devonian to Lower Carboniferous sedimentary successions of a passive continental margin, 6) Carboniferous granitoids, and 7) clastic sediments of Devonian and/or Early Carboniferous intramontane basins. All these components are assembled to form part of the internal Variscan orogenic zone largely exposed within the area of the Bohemian Massif. A three-partite subdivision of the Sudetes proposed here reflects different timing of deformation and exhumation of the respective segments. The Central, West and East Sudetes were deformed and amalgamated during the Middle/Late Devonian, at the turn of the Devonian and Carboniferous and during Early Carboniferous, respectively. Problems in extending the classical tectonostratigraphic zonation of the Variscides into the Sudetes are explained as due to activity of Late Palaeozoic strike-slip faults and shear zones, disrupting and dispersing the initially more simply distributed tectonostratigraphic units into the present-day structural mosaic.

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Palaeotectonics of the area of Miechów Depression in the Jurassic in relation to the SE segment of the Mid-Polish Trough

Złonkiewicz Z.

Volumina Jurassica

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2006

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Vol. 4, no. 1

70-71

EN

Structures reactivated in the basement of the Permian-Mesozoic cover (Fig. 1A) controlled development of the SE segment of Mid-Polish Trough. Facies and thickness patterns in the area of the Laramide Miechów Depression (Złonkiewicz 2006a, b) and adjacent areas verify and complete thesis of analog modeling (McClay et al. 2002; Gutowski & Koyi 2005). They indicate an oblique extension changing from NW to WNW. The NW component affected earlier and stronger the NW part of the area. It caused transtension in reactivated fault systems: the Kraków-Lubliniec (KLF) and Lasocin-Strzelce Dislocation zones (LSDZ). Also an increasing westward tension, earlier and stronger in southern part, may be recognized. Stages of development: I. Hettangian-Bajocian - dextral tension and post-Variscan relaxations. Strike-slip activity of the KLF and LSDZ. The NW- directed stress component down-threw the NW sides of the normal faults: Opoczno-Grójec Fault and the Pilica Fault, rejuvenated on the edge of the Włoszczowa Massif. A slight westward component and relaxations formed a pull-apart rhomboedric system of basins and horsts in down-thrown sides and extended a graben or isolated basin in the LSDZ. II. Bathonian - dextral oblique extension. Dominant stress, directed to NW, supported KLF and LSDZ slip. The coincidence with an increasing westward stress, stronger in the S part, activated a system of en echelone splay faults (strike W-E), posthumous to the Zawiercie Fault (ZF). A second-order system of splay faults (mostly NNW-SSE), bound to ZF, was formed in the Włoszczowa Massif area, leading to formation of grabens and horsts. That pattern was repeated further to the S at the Carpathian front. A basin (W-E) extended at the S border of the Włoszczowa Massif. III. Callovian-Kimmeridgian up to the Hypselocyclum Chron - dextral oblique extension. Increasing westward stress resulted in pull-apart activity and changed a rhombohedric system of horsts and grabens into elongated NW-SE structures. The westward component was stronger in the S part, which resulted in left-hand rotation of the Włoszczowa Massif. The regional uplift, regression and local emersion rebuilt the late-Variscan pattern; an up-thrown Włoszczowa Massif and down-thrown adjacent NW and SE areas. IV. Kimmeridgian from the Divisum Chron onwards-Valanginian - continuation of the palaeotectonic pattern, with dominating westward stress component. Transgression-regression cycle. Extension of the pull-apart structures in the S part of an area. Evolution of the Mid-Polish Trough, extending in front of the East European Craton, depended on varying stress components, produced by extension of rifts in N proto-Atlantic and W Tethys. Palaeotectonic development locates the area of the Miechów Depression between the elevated: Upper Silesian Massif and Holy Cross Mts. (HCM). The HCM belonged to the zone of elevated elements (Gorzów Block, Wielkopolska Ridge, Piotrków Block, Upper San Anticlinorium), typical for the axial part of a basin, separating parallel zones of maximal subsidence. The subsiding zones in the SE segment of the Mid-Polish Trough were located parallel to the edges of HCM (Fig. 1B) in rejuvenated Permian grabens. Observed palaeostress activated a right-hand transfer fault in the deep structure of the Holy Cross Dislocation and formed a positive flower structure in the HCM area.

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Budowa geologiczna i geneza mioceńskiego zrębu Ryszkowej Woli w rejonie Sieniawy-Rudki (wschodnia część zapadliska przedkarpackiego) : wyniki interpretacji danych sejsmiki 3D

Krzywiec P., Aleksandrowski P., Ryzner-Siupik B., Papiernik B., Siupik J., Mastalerz K., Wysocka A., Kasiński J.

Przegląd Geologiczny

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2005

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Vol. 53, nr 8

656--663

EN

The Miocene Carpathian Foredeep Basin in Poland (CFB) developed in front of the Outer Carpathian fold-and-thrust belt, at the junction of the East European craton and the Palaeozoic platform. Within the upper Badenian through Sarmatian deposits of its eastern part, the CFB hosts numerous gas fields. The gas-bearing Miocene succession is characterised by a shallowing-upward trend of sedimentation and consists of offshore hemipelagic, turbiditic and deltaic and nearshore-to-estuarine facies associa-tions. The foredeep basin formation was largely controlled by the structure of its Neoproterozoic–Early Cambrian basement, especially by NW–SE trending faults inherited from Mesozoic tectonic history of SE Poland (subsidence and inversion of the Mid-Polish Trough). Several NW–SE-elongated, narrow basement pop-up structures developed in the northeasternmost part of the CFB, one of them being the Ryszkowa Wola block. The uplift of the pop-up basement block involved Miocene reactivation of older fault zones and resulted in the formation of a narrow, NW–SE elongated Ryszkowa Wola horst (RWH) above it, within the Miocene strata. A complex system of right-stepping, en-echelon, mainly normal faults of predominantly E–W trend, branching off from the NW–SE-striking boundaries of the RWH, has developed around and above the horst, leading to compartmentalisation of the Miocene succession into numerous, mutually displaced and rotated fault blocks. Such an association of deformation structures recognised from the 3D seismics was interpreted in terms of transpressive conditions with the horizontal maximum tectonic compression axis directed š E–W and a sinistral strike-slip displacements on NW–SE striking faults in the basement. The structural interpretation of the Ryszkowa Wola structure proposed here is in line with published results of analogue modelling of fault patterns in sediments overlying active strike-slip discontinuities in a rigid basement. The basement-cover interaction within the Ryszkowa Wola structure in the area of Sieniawa–Rudka was partly coeval with the Miocene deposition of the CFB infill. The uplift and horizontal displacements of the Ryszkowa Wola basement block modified the local subsidence pattern and the organisation of Miocene depositional systems. The syn-depositional strike-slip fault activity in the basement of the CFB resulted in differential movements and rotations of kinematically linked fault-blocks in the Miocene succession around and above the RWH, leading to the formation of numerous gas traps.

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Budowa geologiczna jednostki łysogórskiej (Góry Świętokrzyskie) na podstawie analizy zdjęć radarowych

Mastella L., Mizerski W.

Przegląd Geologiczny

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2002

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Vol. 50, nr 9

767-772

EN

The paper is focused on the geological setting of the Łysogóry Range between the region northwards of Kielce to the eastern ending of the Truskolaska Hill based on the photointerpretation of radar images in the 1:200.000 scale at a resolution ofca. 30 meters. Side selection radar images, taken in concordance with the strike of the geological structures, were chosen for interpretation. The images remove part of the obstracles due to regetation cover and weathered debris. Therefore they are very useful for the recognition of the lithostratigraphy and tectonics of the Łysogóry Unit. Four lithological complexes, corresponding to the previously distinguished lithostratigraphic units, were recognised in the Middle and Upper Cambrian strata. Generally, the Łysogóry Unit is characterised by strata dipping monoclinally northwards. Southern dips occur sporadically within the shale-sandstone complex I, where they are linked with folding. The Łysogóry Unit is delimited bounded by a dislocation (Holy Cross Dislocation) not only from the south, but probably also from the north. Eastwards from Radostowa Hill and Nowa Słupia, the latter dislocation is cut by a series of NE-SW trending sinistral faults. This might indicate its strike-slip, dextral character. Similarly, a series ofNW-SE trending large dextral faults, lying at 25" in relation to the dislocation, accompany the Holy Cross Dislocation. This proves that they are low-angle Riedel shears (R). In this interpretation the presence of a dextral strike-slip component along with the dip-slip component should be assumed. Additionally, in effect of these fault the Łysogóry Unit was flaked, and the individual flakes were husted upon each other. Among the many large regional faults cutting the Łysogóry Unit, the only distinct fault is the Łysogóry Dislocation westwards of Nowa Słupia. The others are invisible in radar images. This is probably caused by the limitations of this method. In effect, the remote sensing method should be supplemented by fieldwork.