--> Abstract: Transition from Convergence to Escape: Field Evidence from the West Carpathians, by M. Nemcok, K. H. Fleischmann, and J. F. Keith, Jr.; #91004 (1991)

Datapages, Inc.Print this page

Transition from Convergence to Escape: Field Evidence from the West Carpathians

NEMCOK, MICHAL, Geologicky Ustav Dionyza Stura, Bratislava, Czechoslovakia, and KARL H. FLEISCHMANN and J. FRANK KEITH, JR., Earth Sciences & Resources Institute, University of South Carolina, Columbia, SC

A large data base of gravimetric, magnetic, seismic, paleomagnetic, lithostratigraphic, sedimentologic, fission-track, bore-hole, and structural information has been used to analyze the structural development of the West Carpathians. These data support a structural model for the evolution of this orogen from convergence to tectonic escape.

The West Carpathians resulted from Cretaceous-Miocene convergence of the European and Apulian plates. Paleocene convergence was northeast directed. With progressive deformation, the central mountain front encountered a shallow wedge-shaped portion of the subducted European plate, which caused a sinistral deflection of convergence trajectories in the western portion of the chain. Beginning with Egerian/Eggenburgian collision and continuing to the present time, the orogen has consisted of two zones: a frontal shortening zone and an internal extensional/strike-slip zone. A cycle of deformation patterns is recognized along the frontal part of the orogen in which remained normal to the West Carpathian front: orogen-vergent thrusting, intermediate back-thrusting, and strike-slip faulting.

Tectonic escape along strike-slip fault sets oriented sub-parallel to the suture zone begun in early Badenian time in the westernmost West Carpathians. The final phase of thrusting becomes younger to the east. The principal compressive stress orientations in areas affected by escape were sub-horizontal and pointed to the location of the last thrust movements along the orogen front. With increased distance from the active collision-suture zone, the principal compressive stress orientations plunged more steeply, indicating a continuous change from a transtensional to an extensional stress regime.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)