Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Variscan Belt

Sortuj według:

Ogranicz wyniki do:

The Sudetic geological mosaic : Insights into the root of the Variscan orogen

Kryza R., Mazur S., Oberc-Dziedzic T.

Przegląd Geologiczny

2004

Vol. 52, nr 8/2

761-773

The Sudetes in the NE part of the Bohemian Massif stretch between the NW–SE-trending Odra Fault Zone and Elbe Fault Zone and represent a structural mosaic which was shaped, predominantly, during the Variscan orogeny. They are composed of various geological units, including basement units in which Neoproterozoic to Carboniferous rocks are exposed, and a post-orogenic cover of younger deposits. During the long history of geological research, the Sudetes have become a “type locality” for a range of important geological phenomena, such as granites and orthogneisses, ophiolites and (meta)volcanic sequences, granulites, eclogites and blueschists, nappe tectonics and terrane concepts. In spite of significant recent achievements, many key problems need further study, and a selection of them is proposed in this paper: (a) the presence of older, Neoproterozoic (Cadomian) rocks and their position within the Variscan collage, (b) the character and emplacement setting of Palaeozoic, pre-Variscan sedimentary successions and magmatic complexes (including ophiolites), (c) structural evolution, metamorphism (in particular HP/T grades) and exhumation of deeper crustal blocks during the Variscan orogeny, and (d) post-orogenic development. Future investigations would require an interdisciplinary approach, combining various geological disciplines: structural geology, petrology, geochemistry, geophysics and geochronology, and, also, multilateral interlaboratory cooperation.

Fold-and-thrust shortening in the western part of the Upper Silesian Coal Basin

Jura D., Kuzak R.

Polish Geological Institute Special Papers

2002

Vol. 7

133-142

The western frame-margin of the Upper Silesian Coal Basin provides good case studies for structural evolution of the fold-and-thrust belt. This study is concerned with tectonic junctions taking place on the Late Variscan front of the Moravosilesian Fold Zone and coal basin. Clues of evolution of fold-and-thrust belt were reconstructed on the base of six cross-sections and using balancing procedure to calculate the shortening. These structural cross-sections illustrated the two principal positive and negative inversion processes of Upper Silesian Coal Basin. The fold shortening varies in range of 25 up to 30% and in low range of 4 up to 18%. The thrust shortening is contrary to fold shortening and changed range of about 10% up to 50%. In the central part of fold-and-thrust belt summarised shortening is 55%, which gradually decreases northward up to 35% and southward up to 30%.