scholarly journals Provenance of the Permian Malužiná Formation sandstones (Malé Karpaty Mountains, Western Carpathians): evidence of garnet and tourmaline mineral chemistry

2015 ◽  
Vol 66 (2) ◽  
pp. 83-97 ◽  
Author(s):  
Marek Vďačný ◽  
Peter Bačík
Keyword(s):  
Regional Metamorphism ◽  
Mineral Chemistry ◽  
Source Rocks ◽  
Granitic Rocks ◽  
Western Carpathians ◽  
Low Grade ◽  
Magmatic Rocks ◽  
Potential Source ◽  
Ophiolitic Rocks ◽  
Central Western Carpathians

Abstract The chemistry of detrital garnets (almandine; spessartine-, grossular-, and pyrope-rich almandine; andradite) and mostly dravitic tourmalines from three sandstone samples of the Permian Malužiná Formation in the northern part of the Malé Karpaty Mts (Western Carpathians, SW Slovakia) reveals a great variability of potential source rocks. They comprise (1) low-grade regionally metamorphosed rocks (metacherts, blue schists, metapelites and metapsammites), (2) contact-thermal metamorphic calcareous rocks (skarns or rodingites), (3) garnet-bearing mica schists and gneisses resulting from the regional metamorphism of argillaceous sediments, (4) amphibolites and metabasic sub-ophiolitic rocks, (5) granulites, (6) Li-poor granites and their associated pegmatites and aplites as well as (7) rhyolites. Consequently, the post-Variscan, rift-related sedimentary basin of the Malužiná Formation originated in the vicinity of a low- to high-grade crystalline basement with granitic rocks. Such lithological types of metamorphic and magmatic rocks are characteristic for the Variscan terranes of the Central Western Carpathians (Tatricum and Veporicum Superunits).

scholarly journals Structural pattern and emplacement mechanisms of the Krížna cover nappe (Central Western Carpathians)

2012 ◽  
Vol 63 (1) ◽  
pp. 13-32 ◽  
Author(s):  
Roberta Prokešová ◽  
Dušan Plašienka ◽  
Rastislav Milovský
Keyword(s):  
Driving Forces ◽  
Structural Evolution ◽  
Evolutionary Model ◽  
Structural Data ◽  
Western Carpathians ◽  
Low Grade ◽  
Structural Pattern ◽  
Thrust Tectonics ◽  
Central Western Carpathians ◽  
Nappe Emplacement

Structural pattern and emplacement mechanisms of the Krížna cover nappe (Central Western Carpathians)The Central Western Carpathians are characterized by both the thick- and thin-skinned thrust tectonics that originated during the Cretaceous. The Krížna Unit (Fatric Superunit) with a thickness of only a few km is the most widespread cover nappe system that completely overthrusts the Tatric basement/cover superunit over an area of about 12 thousands square km. In searching for a reliable model of its origin and emplacement, we have collected structural data throughout the nappe body from its hinterland backstop (Veporic Superunit) to its frontal parts. Fluid inclusion (FI) data from carbonate cataclastic rocks occurring at the nappe sole provided useful information about the p-T conditions during the nappe transport. The crucial phenomena considered for formulation of our evolutionary model are: (1) the nappe was derived from a broad rifted basinal area bounded by elevated domains; (2) the nappe body is composed of alternating, rheologically very variable sedimentary rock complexes, hence creating a mechanically stratified multilayer; (3) presence of soft strata serving as décollement horizons; (4) stress and strain gradients increasing towards the backstop; (5) progressive internal deformation at very low-grade conditions partitioned into several deformation stages reflecting varying external constraints for the nappe movement; (6) a very weak nappe sole formed by cataclasites indicating fluid-assisted nappe transport during all stages; (7) injection of hot overpressured fluids from external sources (deformed basement units) facilitating frontal ramp overthrusting under supralithostatic conditions. It was found that no simple mechanical model can be applied, but that all known principal emplacement mechanisms and driving forces temporarily participated in progressive structural evolution of the nappe. The rear compression operated during the early stages, when the sedimentary succession was detached, shortened and transported over the frontal ramp. Subsequently, gravity spreading and gliding governed the final nappe emplacement over the unconstrained basinal foreland.

Rapid fluid-driven transformation of lower continental crust associated with thrust-induced shear heating

2020 ◽  
Author(s):  
Bjørn Jamtveit ◽  
Kristina G. Dunkel ◽  
Arianne Petley-Ragan ◽  
Fernando Corfu ◽  
Dani W. Schmid
Keyword(s):  
Regional Metamorphism ◽  
Shear Zones ◽  
Amphibolite Facies ◽  
Source Rocks ◽  
Granitic Rocks ◽  
Time Interval ◽  
Fluid Infiltration ◽  
Facies Metamorphism ◽  
Shear Heating ◽  
Host Rocks

<p>Caledonian eclogite- and amphibolite-facies metamorphism of initially dry Proterozoic granulites in the Lindås Nappe of the Bergen Arcs, Western Norway, is driven by fluid infiltration along faults and shear zones. The granulites are also cut by numerous dykes and pegmatites that are spatially associated with metamorphosed host rocks. U-Pb geochronology was performed to constrain the age of fluid infiltration and metamorphism. The ages obtained demonstrate that eclogite- and amphibolite-facies metamorphism were synchronous within the uncertainties of our results and occurred within a maximum time interval of 5 Myr, with a mean age of ca. 426 Ma.  Caledonian dykes and pegmatites are granitic rocks characterised by a high Na/K-ration, low REE-abundance and positive anomalies of Eu, Ba, Pb, and Sr. The most REE-poor compositions show HREE-enrichment. Melt compositions are consistent with wet melting of plagioclase- and garnet-bearing source rocks. The most likely fluid source is dehydration of Paleozoic metapelites, located immediately below the Lindås part of the Jotun-Lindås microcontinent, during eastward thrusting over the extended margin of Baltica. Melt compositions and thermal modelling suggest that short-lived fluid-driven metamorphism of the Lindås Nappe granulites was related to shear heating at lithostatic pressures in the range 1.0-1.5 GPa. High-P (≈2 GPa) metamorphism within the Nappe was related to weakening-induced pressure perturbations, not to deep burial. Our results emphasize that both prograde and retrograde metamorphism may proceed rapidly during regional metamorphism and that their time-scales may be coupled through local production and consumption of fluids.</p>

scholarly journals Thermal evolution of the Malá Fatra Mountains (Central Western Carpathians): insights from zircon and apatite fission track thermochronology

2010 ◽  
Vol 61 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Martin Danišík ◽  
Milan Kohút ◽  
Igor Broska ◽  
Wolfgang Frisch
Keyword(s):  
Fission Track ◽  
Thermal Evolution ◽  
Western Carpathians ◽  
Low Grade ◽  
Apatite Fission Track ◽  
Metamorphic Overprint ◽  
Fission Track Thermochronology ◽  
Fast Cooling ◽  
Central Western Carpathians ◽  
Early Late

Thermal evolution of the Malá Fatra Mountains (Central Western Carpathians): insights from zircon and apatite fission track thermochronologyWe apply zircon and apatite fission track thermochronology (ZFT and AFT, respectively) to the Variscan crystal-line basement of the Malá Fatra Mts (Central Western Carpathians) in order to constrain the thermal history. The samples yielded three Early Cretaceous ZFT ages (143.7±9.6, 143.7±8.3, 135.3±6.9 Ma) and one Eocene age (45.2±2.1 Ma), proving that the basement was affected by a very low-grade Alpine metamorphic overprint. Although the precise timing and mechanisms of the overprint cannot be unequivocally resolved, we propose and discuss three alternative explanations: (i) a Jurassic/Cretaceous thermal event related to elevated heat flow associated with extensional tectonics, (ii) early Late Cretaceous thrusting and/or (iii) an Eocene orogeny. Thermal modelling of the AFT cooling ages (13.8±1.4 to 9.6±0.6 Ma) revealed fast cooling through the apatite partial annealing zone. The cooling is interpreted in terms of exhumation of the basement and creation of topographic relief, as corroborated by the sedimentary record in the surrounding Neogene depressions. Our AFT results significantly refine a general exhumation pattern of basement complexes in the Central Western Carpathians. A younging of AFT ages towards the orogenic front is evident, where all the external massifs located closest to the orogenic front (including Malá Fatra Mts) were exhumed after ~13 Ma from temperatures above ~120 °C.

Polymetamorphism in the Archean Hemlo – Heron Bay greenstone belt, Superior Province: P–T variations and implications for tectonic evolution

1993 ◽  
Vol 30 (5) ◽  
pp. 985-996 ◽  
Author(s):  
Yuanming Pan ◽  
Michael E. Fleet
Keyword(s):  
Greenstone Belt ◽  
Regional Metamorphism ◽  
Mineral Chemistry ◽  
Superior Province ◽  
Low Grade ◽  
Garnet Porphyroblasts ◽  
Metamorphic History ◽  
Tectonic Environment ◽  
History Of ◽  
Archean Greenstone Belt

The tectono-metamorphic history of the late Archean (2800–2600 Ma) Hemlo – Heron Bay greenstone belt in the Superior Province has been delineated from textural relationships, mineral chemistry, and P–T paths in metapelites, cordierite–orthoamphibole rocks, and metabasites from the White River exploration property, Hemlo area, Ontario. An early low-temperature, medium-pressure metamorphism (about 500 °C and 6–6.5 kbar (1 kbar = 100 MPa)) is indicated by the occurrence of relict kyanite and staurolite porphyroblasts and zoned garnet porphyroblasts in metapelites and the presence of zoned calcic amphiboles in metabasites. This early metamorphism appears to have been coeval with the previously documented D1 deformation that is associated with, for example, low-angle thrusts. A second regional metamorphism predominates in the Hemlo – Heron Bay greenstone belt and is generally of relatively low grade, at about 510–530 °C and 3.2–3.5 kbar, over most of the study area and increases to medium grade (550–650 °C and 4–5 kbar) towards the southern margin with the Pukaskwa Gneissic Complex and along the central axis enclosing the Hemlo Shear Zone. The second regional metamorphism was contemporaneous with the D3 deformation and was probably related to plutonism. This type of polymetamorphism in the Hemlo – Heron Bay greenstone belt may be equivalent to those in Phanerozoic subduction complexes and therefore supports the arc–arc accretion model for the development of the southern Superior Province. Although the Hemlo – Heron Bay greenstone belt most likely represents a single tectonic environment (an oceanic island arc), the restricted occurrence of the relict kyanite and staurolite indicates that the central portion of this Archean greenstone belt probably was at a deeper crustal level at the time of the first metamorphic event.

U–Pb geochronometry in the Horseranch Range, northern Omineca Belt, British Columbia, Canada

1994 ◽  
Vol 31 (2) ◽  
pp. 341-350
Author(s):  
Heather E. Plint ◽  
Randall R. Parrish
Keyword(s):  
British Columbia ◽  
Regional Metamorphism ◽  
Granitic Rocks ◽  
Precambrian Basement ◽  
North Central ◽  
Magmatic Rocks ◽  
Granitic Magmatism ◽  
Common Observation ◽  
Western Side ◽  
Dextral Strike Slip

A U–Pb geochronometric study of granitic rocks in the Horseranch Range in the northern Omineca Belt, north-central British Columbia, was carried out to determine the age of deformation, metamorphism, and magmatism and to determine if Precambrian basement is exposed in the range.Our results document Eocene (48–54 Ma) and late Early Cretaceous (113 Ma) granitic magmatism, limit the regional schistosity development to 113 Ma and older, and constrain the peak of syn- to posttectonic regional metamorphism to about 113 Ma. There is no direct evidence for Jurassic metamorphism, although our data do not preclude it. Dextral, oblique-slip mylonitization along the western side of the range is, in part, of Eocene age and related to transtensional tectonics synchronous with movement along regional, dextral strike-slip faults. No Precambrian basement was identified. However, U–Pb data indicate Early Proterozoic inheritance in some of the granitic rocks, a common observation in magmatic rocks of the Omineca Belt.

Extending the ancient margin outboard in the Canadian Cordillera: record of Proterozoic crust and Paleocene regional metamorphism in the Nicola horst, southern British Columbia

2002 ◽  
Vol 39 (11) ◽  
pp. 1605-1623 ◽  
Author(s):  
Philippe Erdmer ◽  
John M Moore ◽  
Larry Heaman ◽  
Robert I Thompson ◽  
Ken L Daughtry ◽  
...  
Keyword(s):  
British Columbia ◽  
Regional Metamorphism ◽  
Geological Mapping ◽  
Detrital Zircons ◽  
Source Rocks ◽  
Late Triassic ◽  
Low Grade ◽  
Rock Types ◽  
Ductile Flow ◽  
Juvenile Crust

The Nicola horst exposes plutonic and amphibolite-grade metamorphic rocks and is surrounded by low-grade arc rocks of the Late Triassic Nicola Group. We present new geological mapping and U–Pb, Nd, and metamorphic data for the Nicola horst near Bob Lake, ~40 km south of Kamloops, British Columbia. The Bob Lake assemblage includes felsic to intermediate metavolcaniclastic rocks, metaconglomerate, schist, phyllite, and other rock types. From U–Pb zircon analysis, a felsic metaporphyry clast in metaconglomerate is 1.04 Ga old. The oldest detrital zircons in metaconglomerate and schist are also near 1 Ga. The Bob Lake assemblage was intruded by 230 Ma tonalite, 219 Ma diorite, and 64 Ma leucogranite and includes 161 Ma felsic porphyry and 157 Ma rhyodacite. Amphibolite-grade metamorphism and ductile flattening and stretching affected all rocks except crosscutting Paleocene granite and granodiorite. The high-grade rocks may be exposed as a result of latest Cretaceous – Eocene extensional ductile flow beneath a thin brittle upper crust. A thickness of ~20 km of juvenile crust beneath the proposed Quesnel terrane is inconsistent with the evidence of Proterozoic source rocks at surface. We infer that most of the crustal lithosphere in this part of the Intermontane Belt is continental, which does not preclude possibly thick arc rocks in other parts. The local thinness of the Nicola Group, however, is inconsistent with emplacement as a regional allochthon and thus with their inclusion in a Quesnel "terrane." The Nicola arc succession appears to have been built on the ancient continental margin.

Stages of Late Palaeozoic deformation and intrusive activity in the western part of the North Patagonian Massif (southern Argentina) and their geotectonic implications

2008 ◽  
Vol 146 (1) ◽  
pp. 48-71 ◽  
Author(s):  
W. VON GOSEN
Keyword(s):  
Regional Metamorphism ◽  
The North ◽  
Magmatic Rocks ◽  
Late Palaeozoic ◽  
Intrusive Rocks ◽  
Gondwana Margin ◽  
Intrusive Activity ◽  
Magmatic History ◽  
Crust Deformation ◽  
Deformational Event

AbstractAnalyses of structures in the western part of the North Patagonian Massif (southern Argentina) suggest a polyphase evolution, accompanied by continuous intrusive activity. The first two deformations (D1, D2) and metamorphism affected the upper Palaeozoic, partly possibly older Cushamen Formation clastic succession and different intrusive rocks. A second group of intrusions, emplaced after the second deformational episode (D2), in many places contain angular xenoliths of the foliated country rocks, indicating high intrusive levels with brittle fracturing of the crust. Deformation of these magmatic rocks presumably began during (the final stage of) cooling and continued under solid-state conditions. It probably coincided with the third deformational event (D3) in the country rocks. Based on published U–Pb zircon ages of deformed granitoids, the D2-deformation and younger event along with the regional metamorphism are likely to be Permian in age. An onset of the deformational and magmatic history during Carboniferous times, however, cannot be excluded. The estimated ~W–E to NE–SW compression during the D2-deformation, also affecting the first group of intrusive rocks, can be related to subduction beneath the western Patagonia margin or an advanced stage of collisional tectonics within extra-Andean Patagonia. The younger ~N–S to NE–SW compression might have been an effect of oblique subduction in the west and/or continuing collision-related deformation. As a cause for its deviating orientation, younger block rotations during strike-slip faulting cannot be excluded. The previous D2-event presumably also had an effect on compression at the northern Patagonia margin that was interpreted as result of Patagonia's late Palaeozoic collision with the southwestern Gondwana margin. With the recently proposed Carboniferous subduction and collision south of the North Patagonian Massif, the entire scenario might suggest that Patagonia consists of two different pieces that were amalgamated with southwestern Gondwana during Late Palaeozoic times.

Progressive Regional Metamorphism in Southern New Zealand

1938 ◽  
Vol 75 (4) ◽  
pp. 160-174 ◽  
Author(s):  
F. J. Turner
Keyword(s):  
New Zealand ◽  
Regional Metamorphism ◽  
Parent Rock ◽  
Chemical Compositions ◽  
Low Grade ◽  
Scottish Highlands ◽  
The Past ◽  
Structural Peculiarities ◽  
Chemical Conditions ◽  
Pelitic Rocks

During the past ten years a number of papers dealing with progressive regional metamorphism in the southern portion of New Zealand have been published. In the following pages a brief summary of the assemblages of minerals typical of the various metamorphic zones is given, but the writer's main object is to draw attention to certain mineralogical and structural peculiarities that appear to differ in some degree from what are usually regarded as the normal features of regional metamorphism in such classic areas as the Scottish Highlands and the Caledonian chain of Norway. The possibility that such departures from the normal may in some instances be connected with chemical peculiarities in the parent rock is suggested by such phenomena as the well-known general limitation of chloritoid, staurolite, and low-grade garnets to pelitic rocks of special chemical compositions. Other unusual features, especially when found to recur in widely separated regions, may well be governed by some particular combination of physical rather than chemical conditions.

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