scholarly journals Tectonic evolution of the southeastern part of the Pohorje Mountains (Eastern Alps, Slovenia)

2010 ◽  
Vol 61 (6) ◽  
pp. 451-461 ◽  
Author(s):  
Frederik Kirst ◽  
Sascha Sandmann ◽  
Thorsten Nagel ◽  
Nikolaus Froitzheim ◽  
Marian Janák
Keyword(s):  
Tectonic Evolution ◽  
Eastern Alps ◽  
Ultrahigh Pressure ◽  
Core Complex ◽  
Southeastern Part ◽  
Metasedimentary Rocks ◽  
Ultramafic Complex ◽  
Intracontinental Subduction ◽  
Metamorphic Core ◽  
East West

Tectonic evolution of the southeastern part of the Pohorje Mountains (Eastern Alps, Slovenia)Field relations and deformation structures in the southeastern part of the Pohorje Mountains constrain the tectonic evolution of the Austroalpine high-pressure/ultrahigh pressure (HP/UHP) terrane. The Slovenska Bistrica Ultramafic Complex (SBUC) forms a large (ca. 8 × 1 km size) body of serpentinized harzburgite and dunite including minor garnet peridotite and is associated with partly amphibolitized eclogite bodies. The SBUC occurs in the core of an isoclinal, recumbent, northward closing antiform and is mantled by metasedimentary rocks, mostly gneisses and a few marbles, including isolated eclogite/amphibolite lenses. Before this folding, the SBUC formed the deepest part of the exposed terrane. We interpret the SBUC to be derived from near-MOHO, uppermost mantle which was intruded by gabbros in the subsurface of a Permian rift zone. During Cretaceous intracontinental subduction, the SBUC was most likely part of the footwall plate which experienced HP to UHP metamorphism and was folded during exhumation. In the Miocene, the Pohorje Pluton intruded and, subsequently, the metamorphic rocks together with the pluton were deformed probably due to east-west extension and contemporaneous north-south shortening, thus forming an antiformal metamorphic core complex.

scholarly journals Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps

2013 ◽  
Vol 608 ◽  
pp. 1201-1225 ◽  
Author(s):  
Shuyun Cao ◽  
Franz Neubauer ◽  
Manfred Bernroider ◽  
Junlai Liu ◽  
Johann Genser
Keyword(s):  
Eastern Alps ◽  
Metamorphic Core Complex ◽  
Core Complex ◽  
Metamorphic Core

scholarly journals Evidence for and significance of the Late Cretaceous Asteroussia event in the Gondwanan Ios basement terranes

Solid Earth ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 2255-2275
Author(s):  
Sonia Yeung ◽  
Marnie Forster ◽  
Emmanuel Skourtsos ◽  
Gordon Lister
Keyword(s):  
Late Cretaceous ◽  
Tectonic Evolution ◽  
Microstructural Analysis ◽  
Core Complex ◽  
Medium Temperature ◽  
Western Tethys ◽  
Pressure Medium ◽  
Extreme Extension ◽  
The Individual ◽  
Metamorphic Core

Abstract. The Late Cretaceous Asteroussia event as recorded in the Cyclades is a potential key to the tectonic evolution of Western Tethys. Microstructural analysis and 40Ar/39Ar geochronology on garnet–mica schists and the underlying granitoid basement terrane on the island of Ios demonstrates evidence of a Late Cretaceous high-pressure, medium-temperature (HP–MT) metamorphic event. This suggests that the Asteroussia crystalline nappe on Crete extended northward to include these Gondwanan tectonic slices. In this case, the northern part of the Asteroussia nappe (on Ios) is overlain by the terrane stack defined by the individual slices of the Cycladic Eclogite–Blueschist Unit, whereas in the south (in Crete) the Asteroussia slices are near the top of a nappe stack defined by the individual tectonic units of the external Hellenides. This geometry implies that accretion of the Ios basement terrane involved a significant leap of the subduction megathrust (250–300 km) southward. Accretion needs to have commenced at or about ∼38 Ma, when the already partially exhumed slices of the Cycladic Eclogite–Blueschist Unit began to thrust over the Ios basement. By ∼35–34 Ma, the subduction jump had been accomplished, and renewed rollback began the extreme extension that led to the exhumation of the Ios metamorphic core complex.

Influence of inherited Indian basement faults on the evolution of the Himalayan Orogen

2018 ◽  
Vol 481 (1) ◽  
pp. 251-276 ◽  
Author(s):  
Laurent Godin ◽  
Renaud Soucy La Roche ◽  
Lindsay Waffle ◽  
Lyal B. Harris
Keyword(s):  
Tectonic Evolution ◽  
Eastern Himalaya ◽  
Centrifuge Modelling ◽  
Himalayan Orogen ◽  
Basement Faults ◽  
Basement Fault ◽  
Indian Lithosphere ◽  
Metamorphic Core ◽  
The Himalaya ◽  
East West

AbstractIndian basement faults, which bound three orogen-perpendicular palaeotopographic ridges of Precambrian Indian basement south of the Himalaya, extend to the base of the Indian lithosphere and to the northern extent of the Indian lithosphere underneath Tibet. In the eastern Himalaya, the active orogen-perpendicular Yadong–Gulu graben is aligned with an earthquake-generating strike-slip fault in the high Himalaya. We argue that the graben results from crustal necking during reactivation of the underplated basement fault. In the central Himalaya, along-strike diachronous deformation and metamorphism within the Himalayan metamorphic core, as well as lateral ramps in the foreland thrust belt, spatially correspond to the Lucknow and Pokhara lineaments that bound the subsurface Faizabad Ridge in the Indian basement. Analogue centrifuge modelling confirms that offset along such deep-seated basement faults can affect the location, orientation and type of structures developed at various stages of orogenesis and suggests that it is mechanically feasible for strain to propagate through a melt-weakened mid-crust. We suggest that inherited Indian basement faults affect the ramp-flat geometry of the basal Main Himalayan Thrust, partition the Himalayan range into distinct zones, localize east–west extension resulting in the Tibetan graben and, ultimately, contribute to lateral variability in tectonic evolution along the orogen's strike.

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