scholarly journals Cenozoic deformation in the Tauern Window (Eastern Alps) constrained by in situ Th-Pb dating of fissure monazite

Solid Earth ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 437-467 ◽  
Author(s):  
Emmanuelle Ricchi ◽  
Christian A. Bergemann ◽  
Edwin Gnos ◽  
Alfons Berger ◽  
Daniela Rubatto ◽  
...  
Keyword(s):  
Thermal Evolution ◽  
Structural Data ◽  
Shear Zones ◽  
Eastern Alps ◽  
Strike Slip ◽  
Major Peak ◽  
Tauern Window ◽  
Two Phases ◽  
Fissure Formation

Abstract. Thorium–lead (Th-Pb) crystallization ages of hydrothermal monazites from the western, central and eastern Tauern Window provide new insights into Cenozoic tectonic evolution of the Tauern metamorphic dome. Growth domain crystallization ages range from 21.7 ± 0.4 to 10.0 ± 0.2 Ma. Three major periods of monazite growth are recorded between ∼ 22–20 (peak at 21 Ma), 19–15 (major peak at 17 Ma) and 14–10 Ma (major peak around 12 Ma), respectively, interpreted to be related to prevailing N–S shortening, in association with E–W extension, beginning strike-slip movements and reactivation of strike-slip faulting. Fissure monazite ages largely overlap with zircon and apatite fission track data. Besides tracking the thermal evolution of the Tauern dome, monazite dates reflect episodic tectonic movement along major shear zones that took place during the formation of the dome. Geochronological and structural data from the Pfitschtal area in the western Tauern Window show the existence of two cleft generations separated in time by 4 Ma and related to strike-slip to oblique-slip faulting. Moreover, these two phases overprint earlier phases of fissure formation. Highlights. In situ dating of hydrothermal monazite-(Ce). New constraints on the exhumation of the Tauern metamorphic dome. Distinct tectonic pulses recorded from east to west.

scholarly journals Cenozoic deformation in the Tauern Window (Eastern Alps, Austria) constrained by in-situ Th-Pb dating of fissure monazite

2019 ◽  
Author(s):  
Emmanuelle Ricchi ◽  
Christian A. Bergemann ◽  
Edwin Gnos ◽  
Alfons Berger ◽  
Daniela Rubatto ◽  
...  
Keyword(s):  
Thermal Evolution ◽  
Structural Data ◽  
Shear Zones ◽  
Eastern Alps ◽  
Strike Slip ◽  
Tauern Window ◽  
Dome Growth ◽  
Two Phases ◽  
Fissure Formation

Abstract. Thorium-Pb crystallization ages of hydrothermal monazites from the western, central and eastern Tauern Window provide new insights into Cenozoic tectonic evolution of the Tauern metamorphic dome. Growth domain crystallization ages range from 22.3 ± 0.6 Ma to 7.7 ± 0.9 Ma. Three major periods of monazite growth are recorded between ~ 22–19 (peak at 21 Ma), 19–15 (major peak at 17 Ma) and 13–8 Ma (major peaks at 12, 10 and 8 Ma), respectively interpreted to be related to prevailing N-S shortening, in association with E-W extension, beginning strike-slip movements, and reactivation of strike-slip faulting. Fissure monazite ages largely overlap with zircon and apatite fission tracks data. Besides tracking the thermal evolution of the Tauern dome, monazite dates reflect episodic tectonic movement along major shear zones that took place during the formation of the dome. Geochronological and structural data from the Pfitschtal area in the western Tauern Window show the existence of two cleft generations separated in time by 4 Ma and related to strike-slip to oblique-slip faulting. Moreover, these two phases overprint earlier phases of fissure formation.

scholarly journals Neogene kinematics of the Giudicarie Belt and eastern Southern Alpine orogenic front (Northern Italy)

2021 ◽  
Author(s):  
Vincent F. Verwater ◽  
Eline Le Breton ◽  
Mark R. Handy ◽  
Vincenzo Picotti ◽  
Azam Jozi Najafabadi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Eastern Alps ◽  
Strike Slip ◽  
Fault System ◽  
Late Oligocene ◽  
Lateral Variation ◽  
Tectonic Structures ◽  
Tauern Window ◽  
Adriatic Plate ◽  
Lateral Extrusion

Abstract. Neogene indentation of the Adriatic plate into Europe led to major modifications of the Alpine orogenic structures and style of deformation in the Eastern Alps. Especially, the offset of the Periadriatic Fault by the Northern Giudicarie Fault marks the initiation of strike-slip faulting and lateral extrusion of the Eastern Alps. Questions remain on the exact role of this fault zone in changes of the Alpine orogen at depth. This necessitates quantitative analysis of the shortening, kinematics and depth of decoupling underneath the Northern Giudicarie Fault and associated fold-and thrust belt in the Southern Alps. Tectonic balancing of a network of seven cross sections through the Giudicarie Belt parallel to the local shortening direction reveals that it comprises two kinematic domains with different amounts and partly overlapping ages of shortening. These two domains are delimitated by the NW-SE oriented strike-slip Trento-Cles – Schio-Vicenza fault system, cross-cutting the Southern Alpine orogenic front in the south and merging with the Northern Giudicarie Fault in the north. The SW kinematic domain (Val Trompia sector) accommodated at least ~18 km of Late Oligocene to Early Miocene shortening. Since the Middle Miocene, the SW kinematic domain experienced a minimum of ~12–22 km shortening, whereas the NE kinematic domain underwent at least ~25–35 km shortening. Together, these domains contributed to an estimated ~53–75 km of sinistral strike-slip motion along the Northern Giudicarie Fault, implying that (most of) the offset of the Periadriatic Fault is due to Late Oligocene to Neogene indentation of the Adriatic plate into the Eastern Alps. Moreover, the faults linking the Giudicarie Belt with the Northern Giudicarie Fault reach ~15–20 km depth, indicating a thick-skinned tectonic style of deformation. These fault detachments may also connect at depth with a lower crustal Adriatic wedge that protruded north of the Periadriatic Fault and was responsible for N-S shortening and eastward escape of deeply exhumed units in the Tauern Window. Finally, the east-west lateral variation of shortening indicates internal deformation and lateral variation in strength of the Adriatic indenter, related to Permian – Mesozoic tectonic structures and paleogeographic domains.

scholarly journals Supplementary material to "Cenozoic deformation in the Tauern Window (Eastern Alps, Austria) constrained by in-situ Th-Pb dating of fissure monazite"

2019 ◽  
Author(s):  
Emmanuelle Ricchi ◽  
Christian A. Bergemann ◽  
Edwin Gnos ◽  
Alfons Berger ◽  
Daniela Rubatto ◽  
...  
Keyword(s):  
Eastern Alps ◽  
Tauern Window ◽  
Supplementary Material

scholarly journals Timing of Paleozoic Exhumation and Deformation of the High-Pressure Vestgӧtabreen Complex at the Motalafjella Nunatak, Svalbard

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 125 ◽  
Author(s):  
Christopher J. Barnes ◽  
Katarzyna Walczak ◽  
Emilie Janots ◽  
David Schneider ◽  
Jarosław Majka
Keyword(s):  
High Pressure ◽  
Tectonic Evolution ◽  
Shear Zones ◽  
White Mica ◽  
Strike Slip ◽  
Structural Studies ◽  
Metamorphic Overprint ◽  
Subaerial Exposure ◽  
Facies Metamorphism

The Vestgӧtabreen Complex exposed in the Southwestern Caledonian Basement Province of Svalbard comprises two Caledonian high-pressure units. In situ white mica 40Ar/39Ar and monazite Th-U-total Pb geochronology has resolved the timing of the tectonic evolution of the complex. Cooling of the Upper Unit during exhumation occurred at 476 ± 2 Ma, shortly after eclogite-facies metamorphism. The two units were juxtaposed at 454 ± 6 Ma. This was followed by subaerial exposure and deposition of Bullbreen Group sediments. A 430–400 Ma late Caledonian phase of thrusting associated with major sinistral shearing throughout Svalbard deformed both the complex and the overlying sediments. This phase of thrusting is prominently recorded in the Lower Unit, and is associated with a pervasive greenschist-facies metamorphic overprint of high-pressure lithologies. A c. 365–344 Ma geochronological record may represent an Ellesmerian tectonothermal overprint. Altogether, the geochronological evolution of the Vestgӧtabreen Complex, with previous petrological and structural studies, suggests that it may be a correlative to the high-pressure Tsäkkok Lens in the Scandinavian Caledonides. It is suggested that the Vestgӧtabreen Complex escaped to the periphery of the orogen along the sinistral strike-slip shear zones prior to, or during the initial stages of continental collision between Baltica and Laurentia.

Proterozoic geological evolution of the northern Vestfold Hills, Antarctica

1991 ◽  
Vol 128 (4) ◽  
pp. 307-318 ◽  
Author(s):  
C. W. Passchier ◽  
R. F. Bekendam ◽  
J. D. Hoek ◽  
P. G. H. M. Dirks ◽  
H. de Boorder
Keyword(s):  
Large Scale ◽  
Structural Evolution ◽  
Shear Zones ◽  
Granulite Facies ◽  
Strike Slip ◽  
Amphibolite Facies ◽  
Tectonic Event ◽  
Vestfold Hills ◽  
Two Phases ◽  
Brittle Faulting

AbstractThe presence of polyphase shear zones transected by several suites of dolerite dykes in Archaean basement of the Vestfold Hills, East Antarctica, allows a detailed reconstruction of the local structural evolution. Archaean and early Proterozoic deformation at granulite facies conditions was followed by two phases of dolerite intrusion and mylonite generation in strike-slip zones at amphibolite facies conditions. A subsequent middle Proterozoic phase of brittle normal faulting led to the development of pseudotachylite, predating intrusion of the major swarm of dolerite dykes around 1250 Ma. During the later stages and following this event, pseudotachylite veins were reactivated as ductile, mylonitic thrusts under prograde conditions, culminating in amphibolite facies metamorphism around 1000–1100 Ma. This is possibly part of a large-scale tectonic event during which the Vestfold block was overthrust from the south. In a final phase of strike-slip deformation, several pulses of pseudotachylite-generating brittle faulting alternated with ductile reactivation of pseudotachylite.

Extension and transtension associated with strike-slip faults and its relation with aquifer potentials: a case study in Aravalli terrane (North Gujarat), India

2020 ◽  
Author(s):  
Rudra Mohan Pradhan ◽  
Tapas Kumar Biswal
Keyword(s):  
Complex Geometry ◽  
Fractured Rock ◽  
Primary Source ◽  
Structural Data ◽  
Shear Zones ◽  
Structural Features ◽  
Strike Slip ◽  
Normal Faults ◽  
Fold Belt ◽  
North Gujarat

<p>Fractured rock aquifers are one of the most difficult aquifers to characterize due to complex geometry and fracture network. In Aravalli terranes of North Gujarat, communities depend on basement rock aquifers as the primary source of water supply. The hydrogeology of these aquifers is poorly understood and the drinking/irrigation wells are frequently placed in this area with little appreciation of the fracture systems. Increasing water demand puts stress to explore groundwater from less reliable sources of basement rocks and hence, makes it vital to identify potential hydrogeological zones. Lineament studies are commonly used for targeting groundwater bearing zones in hard rock terrane and very often ignore the other important structural settings viz. extension, transtension etc. For the present study, structural data pertaining faults and fractures have been mapped through fieldwork and Electrical resistivity imaging (ERT) technique. The key objective of the study is to correlate the structural features (extensional and transtensional settings) with geophysical profiles and to find out potential hydrogeological zones from where water can be explored economically. The study area comes under the Ambaji basin of Aravalli-Delhi fold belt which is a Proterozoic fold belt running 700-800 km in NE-SW direction and situated in NW India. The Aravalli-Delhi fold belt had undergone multiple phases of deformation. In this area, three major sets of fractures are present and are oriented largely in WNW-ESE, NE-SW, and NW-SE direction. The WNW-ESE fracture is dextral in nature which has interpreted from the displacement of fold limbs. Further, these are right lateral en-echelon normal faults where NE-SW extension has been taken place. There is another set of fracture i.e. NW-SE which is due to stretching of strike-slip fault. The ductile shear zones in the area are also parallel to the NW-SE fracture set. The shear zones are opened-up due to extension and formed potential aquifers. ERT has been carried out along and across the fractures to understand the subsurface fracture geometry. The ERT shows deep sited fractures and low resistivity values at the cross-section of WNW-ESE faults with the shear zone. This concludes a strong correlation between different structural settings with potential aquifers which could be used for pumping as well as artificial recharge sites for long term sustainability.</p><p><strong>Keywords-</strong> Aravalli terrane, Aquifer, Extension, Fracture, ERT</p>

P-T data of Ky-St-Grt gneisses hosting HP amphibolites and eclogites from the Austroalpine Polinik complex, Kreuzeck Mountains, Eastern Alps, Austria

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Martin Michálek ◽  
Marián Putiš ◽  
Christoph Hauzenberger
Keyword(s):  
High Pressure ◽  
Mineral Assemblage ◽  
Eastern Alps ◽  
Strike Slip ◽  
Slip Zone ◽  
Mineral Association ◽  
Lateral Strike Slip ◽  
Tauern Window ◽  
Austroalpine Basement ◽  
T Values

AbstractThis study focuses on metapelites of the Polinik complex in the Kreuzeck Mts. southeast of the Tauern Window, Eastern Alps, where kyanite — staurolite — garnet gneisses host eclogites and high pressure (HP) amphibolites of the Austroalpine basement. The stable mineral assemblage is garnet — staurolite — biotite — kyanite — quartz. Estimated metamorphic conditions from conventional geothermobarometry are 654±30 °C and 0.9±0.08 GPa, and Average P-T values calculated by THERMOCALC, are 665±15 °C at 0.77±0.09 GPa. Formation of the present mineral association in gneisses is related to the exhumation (D2) stage of hosted eclogites/HP amphibolites within a lateral strike-slip zone.

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