Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Acta Geologica Polonica

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Pieniny Klippen Belt (PKB)

Sortuj według:

Ogranicz wyniki do:

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

Jurewicz E., Hercman H., Nejbert K.

Acta Geologica Polonica

2007

Vol. 57, no. 2

187-204

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.

Geodynamic evolution of the Tatra Mts. and the Pieniny Klippen Belt (Western Carpathians) : problems and comments

Jurewicz E.

Acta Geologica Polonica

2005

Vol. 55, no. 3

295-338

The geodynamic evolution of the Pieniny Klippen Belt (PKB) and the Tatra Mts. assumes that: The Oravic-Vahic Basin developed due to Jurassic rifting processes with thinned continental crust. The oblique rift without rift-related volcanism had probably a WSW-ENE course. Late Cretaceous thrust-folding of the Choč, Križna and High-Tatric nappes took place underwater and at considerable overburden pressure (ok. ~6-7 km). The geometry of the structures was strongly disturbed by pressure solution processes leading to considerable mass loss. Nappe-folding in the PKB was connected with the slow and flat subduction of thinned continental crust of the Vahicum-Oravicum under the northern margin of the Central Carpathians Block.In the Tatra Mts. and the PKB, the nappe thrust-folding was influenced by a strike-slip shear zone between the edge of the Central Carpathians and the PKB and caused e.g. the counter-clockwise rotation of the Tatra block and relative changing directions of thrusting. The consequence of Miocene oblique subduction and subsequent collision of the North-European continental crust with the Central Carpathian Block was the activation of NNW-SSE deep fault zones. With one of these - the Dunajec Fault - were connected en echelon shears trading on the andesite dykes swarm. Miocene collision caused the disintegration of the Central Carpathian Block into individual massifs and their rotational uplift. The value of rotation around the horizontal axis for the Tatra Massif is estimated at ~40°.