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Petrophysical control on the mode of shearing in the sedimentary rocks and granitoid core of the Tatra Mountains during Late Cretaceous nappethrusting and folding, Carpathians, Poland

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Jurewicz E.

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tom Vol. 56, no. 2

159-170

EN

In the Tatra Mts., the variability of structures within the granitoid rocks and their sedimentary complexes depends on the physical properties of the rocks, particularly on their porosity and sensibility to dissolution. In the relatively homogeneous and low porosity granitoid rocks, the shear surfaces are planar and smooth without damage zones around the shear planes. They did not develop open spaces during shearing, which prevented fluid migration and hydrotectonic phenomena. In the sedimentary rocks, mechanical, mostly bedding anisotropy controlled the geometry and morphology of the shear zones. High porosity and recurring changing in pore fluid pressure determined the cyclic character of the thrustrelated shearing processes. Fluids appearing within the thrust-fault fissure played the key role in tectonic transport and selective mass-loss processes (hydrotectonic phenomena). The mass-loss process was an effect of mechanical disintegration, pressure solution and cavitation erosion.The multistage character of the thrusting processes resulted in a gradual increase in mass loss value and in geometrical complication of the shear zones. Within the Czerwone Wierchy Nappe, the minimum value of the mass-loss estimated from a restored cross-section is in the range of 15-50%.

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Geometric analysis of steep-dipping dislocations within the granitoid core in the Polish part of the Tatra Mts

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Jurewicz E.

Annales Societatis Geologorum Poloniae

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2002

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tom Vol. 72, No 1

89-98

EN

The paper is focused on steep dipping dislocations within the granitoid core of the Polish part of the Tatra Mts. Two groups of dislocations were distinguished: single faults with flat and smooth planes, and mylonitic and cataclastic zones. With the help of TectonicsFP software, the reconstruction of the stress pattern, responsible for the formation of single faults, is presented basing on slip structures on their planes. The structures can be linked with the Middle Miocene (Sarmatian) 106-120° extension; in effect a set of normal oblique-slip, ~35/60N faults was formed with a horizontal sinistral component. The geometry of the system of mylonitic and cataclastic zones should be analysed after reversing them to positions prior to the post-Palaeogene rotational upheaval of the Tatra Mts. The orientation of some dislocation zones, described in literature, is revised.

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Od dryfu kontynentów Alfreda Wegenera do tektoniki płyt

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Jurewicz E.

Przegląd Geologiczny

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2015

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tom Vol. 63, nr 11

1266--1271

EN

The modern theory of plate tectonics has been the basis of works of several generations of geologists and geophysicists. One of them was Alfred Wegener and his theory of continental drift. The imperfection of the theory (lack of any explanation for the mechanism of continents movement) was the driving force for further studies. The most important ones were the detailed recognition of the ocean floor, and the discovery of the rift and subduction zones.

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Procesy nasunięć płaszczowinowych w Tatrach

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Jurewicz E.

Przegląd Geologiczny

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2012

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tom Vol. 60, nr 8

432–-441

EN

In the Tatra Mts., Late Cretaceous nappe-thrusting processes took place underwater and at considerable overburden pressure. The main decollement level was anisotropic Triassic evaporite rocks (so-called Rauhwacke), whose selective solution significantly influenced the resultant complex geometry of the thrust contacts. High pressure fluids expelled into the thrusts zones facilitated tectonic transport and mass-loss processes. The mass-loss was preceded by pressure solution, hydrofracturing leading to mechanical disintegration, and cavitation erosion (hydrotectonicphenomena). Fluids released to the shear zones acted as a "waterpillow" facilitating the motion of nappes. The multistage character of thrusting resulted in increasing mass loss and in geometrical complexity of the nappe-based shear zone.

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Próba rekonstrukcji pola naprężeń z etapu fałdowań płaszczowinowych w Tatrach na podstawie analizy struktur ślizgowych w trzonie granitowym

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Jurewicz E.

Przegląd Geologiczny

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2000

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tom Vol. 48, nr 3

239-245

PL

Rekonstrukcja alpejskiego pola naprężeń w Tatrach na podstawie struktur występujących w jednostkach płaszczowinowych jest trudna, ponieważ w większości powierzchnie uskoków są słabo czytelne i nie są płaszczyznami. W przeciwieństwie do nasuniętych jednostek, granitoidowy trzon Tatr Wysokich jest względnie izotropowy i nadaje się do geometrycznej analizy mezostruktur. Do rekonstrukcji osi naprężeń z zastosowaniem programu TectonicsFP wybrano płaskie uskoki, o kruchej genezie i z mineralizacją epidotową. Aby dokonać rekonstrukcji alpejskiego pola naprężeń blok tatrzański należało zrotować do pozycji przedeoceńskiej o 40o ku południowi oraz (uwzględniając dane paleomagnetyczne) o 23o w lewo do pozycji sprzed 90 mln lat. Po pierwszej rotacji danych oś naprężenia głównego (s1) przyjęła położenie 355/10 (z młodszego etapu kompresji alpejskiej o kierunku N–S), a po drugiej rotacji 335/10 (ze starszego etapu o kierunku NNW–SSE).

EN

The reconstruction of the alpine stress axes in the Tatra Mts based on structures in nappe units is difficult because most of the fault surface is not flat and unmeasurable. In contrast to overthrusted nappes, the granitoid massif of High Tatra Mts is more iso-tropic and mesostructure populations are suitable to geometrical analysis. Only flat dipping, brittle origin slickensided faults, coated with greenish epidote have been selected to reconstruction of stress axes with TectonicFP programme. Before the stress reconstruction the Tatra Mts block should be rotated about 40° southward to pre-Eocene position and based on the paleomagnetical results about 23" counterclockwise to position older than 90 Ma. After first rotation of datasets the principal stress axe (a/) was found in position 355/10 (the younger stage of alpine contraction during nappes folding and overthrusting - N-S direction) and after second one - 355/10 (the older stage of contraction - NNW-SSE direction).

6

The Zadnie Kamienne "ravenous" shear zone (High-Tatric Nappe) - conditions of deformation

63%

Jurewicz E. , Słaby E.

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2004

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tom Vol. 48, No 4

371--382

EN

The Zadnie Kamienne shear zone is a high-angle Riedel type shear zone (R'), exhibiting an antithetic sense of displacement, which may have developed synchronously with the nappe-thrusting of the Giewont Unit (High-Tatric Nappe). The amount of displacement along this zone is very low and does not explain the very intense deformation, which is of the same character as that at the base of the Giewont Unit (mylonitization, stylolitization and vein forming). The explanation of this phenomenon lies in the multiple activity of this zone, the change of the direction of movement and the important role of pressure solution in hydrothermal conditions responsible for dissolution creep, mass loss and stress relaxation. This kind of shear can be referred to as a "ravenous" shear zone. Neo-forming minerals accompanying these processes were applied as a temperature gauge. Simultaneous growth of albite and adularia indicates a temperature of about 350 degrees C. Chlorites accompanying them occur in two thermal episodes, the first of which indicating a similar temperature (292-357 C).

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Tectonics of the Chęciny Anticline (Holy Cross Mts., Central Poland) in the light of new cartographic data and calcite vein analysis

63%

Jurewicz E. , Stępień U.

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2012

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tom Vol. 56, No 1

95-106

EN

The Variscan orogeny of NE–SW compression has folded the Paleozoic core of the Holy Cross Mountains (Central Poland). The Chęciny Anticline, formed during this tectonic event, is located in the southwestern part of the Kielce Unit. This paper presents structural data from two newly found outcrops of Cambrian rocks that modify the geometric reconstruction of the Chęciny Anticline, especially within its southern limb that is subdivided into two second-order structures: the Rzepka Syncline and the Wrzosy Anticline. The eastern part of the Chęciny Anticline has been reconstructed, pinpointing its fragmentation into a series of blocks (horsts and grabens) separated by faults semi-perpendicular to the anticline axis. New mapping data reveals deep, pre-Triassic erosion of folded Variscan basement, uncovering Cambrian rocks outcropping in the hinge of the Wrzosy Anticline. In the Chęciny Anticline, folding-related shortening has been accompanied by along-strike extension and the formation of syn-tectonic calcite veins, which filled fractures oriented perpendicular to the fold axis. The magnitude of extension has been estimated along a 215 m long main quarry wall of Rzepka Hill, approximately parallel to the Variscan structures and located within the southern limb of the Chęciny Anticline. The total thicknesses of veins filling extension fractures and spaces between clasts in tectonic breccia were summed and indicate 8.4% of strike-parallel extension (~120o) in the Chęciny area. This value was compared to ca. 30% of folding-induced shortening, related to NE–SW late Variscan compression. We hence obtain a strain ratio of 30:8.4 = 3.5. This high value of strain ratio indicates that longitudinal extension was a significant component contributing to the late Variscan deformation in the Kielce Unit.

8

Formation conditions of quartz mineralization in the mylonitic zones and on the slickenside fault planes in the High Tatra granitoids

63%

Jurewicz E. , Kozłowski A.

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2001

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tom T. 54

65-76

EN

Temperature and pressure of quartz formation on the flat dipping slickenside fault planes covered with quartz and epidote, and quartz from veins in mylonitic zones in the High Tatra granitoid have been compared. The data, obtained by studies of fluid inclusions proved that synkinematic quartz on the slickenside fault surfaces crystallized at higher pressure and lower temperature (1.5 – 1.7 kbar, 212 – 254°C) than vein quartz in mylonitic zones (1.3 – 1.6 kbar, 264 – 316°C). Quartz formation on the flat dipping slickenside faults may be bound to the horizontal compression causing the cold-regime Alpine nappe folding, whereas the post-mylonitic quartz veins formed due to hydrothermal activity probably connected with an older, maybe Variscan stage of the granitoid massif formation.

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The tectonics and stratigraphy of the transitional zone between the Pieniny Klippen Belt and Magura Nappe (Szczawnica area, Poland)

63%

Jurewicz E. , Segit T.

Geology, Geophysics and Environment

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2018

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tom Vol. 44, no. 1

127--177

EN

The Pieniny Klippen Belt is a narrow, complex structure stretching along a tectonic boundary between the Central and Outer Carpathians. Its formation involved two main evolutionary stages, the first, related to Late Cretaceous-Paleocene folding and thrusting, and the second, associated with Miocene orogenic events in the Outer Carpathians. Interactions between the Pieniny Klippen Belt and Outer Carpathians during both the sedimentation and deformation stages have resulted in the establishment of a peri-klippen transitional zone (named the Šariš Transitional Zone), in which the tectonic deformation effects gradually decrease towards the north. The stratigraphy and tectonic position of this zone have been controversial for decades. The key stratigraphic problems concern 1) the lithologic identity and position of the Szlachtowa (“black flysch”), Opaleniec and Pieniny formations and 2) the relation of the Jarmuta Formation, associated mainly with the Šariš Transitional Zone, to the Szczawnica and Zarzecze formations of the Magura Nappe. We provide an early Paleogene dinoflagellate cyst stratigraphic record of deposits that, according to some recent reinterpretations, represent the Neogene “Kremna Formation”. The legitimacy of new lithostratigraphic assignments of the “Kremna Formation” at Jaworki is put into question upon the basis of the primacy of units introduced for the same strata earlier.

10

Flowstone-like calcite in the andesite of Jarmuta Mt. - dating the Holocene tectonic activity in the vicinity of Szczawnica (Magura Nappe, Outer Carpathians, Poland)

51%

Jurewicz E. , Hercman H. , Nejbert K.

Acta Geologica Polonica

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2007

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tom Vol. 57, no. 2

187-204

EN

Extensional fractures partly filled with calcite showing the characteristics of flowstone have been observed in the andesite from Jarmuta Mt. The isotopic composition of this calcite indicates low-temperature crystallization conditions and its vadose origin. U-Th dating of the flowstone-like calcite indicates ages of [similar to] 2.5-6.5 ka. The calcite grew on a rough and fresh andesite surface, and hence its age may correspond to the age of the extensional fractures. Rhythmically distributed intergrowths of clay minerals present in the calcite may reflect annual climatic oscillations and show that the calcite grew for at least 500 years. The calcite filling the extensional fractures, like the calcite cementing the loosened cataclastic zones cutting the andesite, does not show any features indicating younger deformations. The origin and geometric features of the fractures show that they could have formed in response to increased strike-slip activity within the deep fault zone known as the Dunajec Fault, which may coincide with the fracture zone between the Upper Silesian and Małopolska blocks.

11

Cavitation erosion - a possible cause of the mass loss within thrust zones in the Tatra Mts., Poland

51%

Jurewicz E. , Gireń B. , Steller J.

Acta Geologica Polonica

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2007

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tom Vol. 57, no. 3

305-323

EN

In the Tatra Mts., thrust-napping and shearing were multi-stage re-activated processes. Their cyclic character was determined by increases and decreases in pore fluid pressure. During each cycle, new parts of the rheologically heterogeneous wall-rock were selectively destroyed due to hydraulic fracturing, brecciation and mylonitization, and moved out as a solution and/or suspension. As a result of these processes, including pressure solution, considerable mass loss could have taken place. All these processes took place under the considerable influence of fluids. In this paper we consider the possible contribution of cavitation erosion to mass loss processes. Displacement along an uneven thrust surface could create chambers filled with fluid and sudden falls in local pressure promoting the inception of cavitation. Cavitation damage, mainly mechanical in nature, could act synergistically with slurry abrasion and pressure solution processes. Our work is of a hypothetical character. To prove the possibility of cavitation erosion within shear zones in the Tatra Mts. we conducted an experiment to show the low resistance of rock samples to cavitation erosion. We also discuss and characterize the conditions essential to induce cavitation within thrust zones at the base of nappes.