The significance of Gosau-type basins for the late Cretaceous tectonic history of the Alpine-Carpathian belt

A key feature of Late Cretaceous tectonics throughout the Alpine-Carpathian -Pannonian (ALCAPA) region is the synchronous formation of sedimentary basi ns (Gosau basins) and exhumation of metamorphic domes. Initial subsidence, spatially varying in time (Cenomanian-Santonian), withi n Gosau-type basins is associated with the development of a fluvial-lacustr ine to shallow marine environment and the deposition of conglomerates, sand stones, coal-bearing marls and rudist limestones were deposited. The progre ssive deepening of the marine basins is documented by a second subsidence p ulse during the Campanian-Early Maastrichtian leading to the establishment of an open marine environment. Gosau basins on top of the Northern Calcareo us Alps and equivalent nappes of the Western Carpathians which were located at or close to the northern to northwestern active margin of the Austroalp ine realm (external basins) locally subsided below the CCD. In contrast a d istinctly shallower water environment prevailed in Gosau basins in central areas of the actively evolving Alpine-Carpathian mountain chain (internal b asins). Deposition of flysch-type deposits is common for the deep-water fac ies. Subsidence analysis of internal Gosau basins were performed and their mutua l relationship to coevally exhuming metamorphic domes, documented by a numb er of geochronologic data, is emphasised. A compilation of these data revea led a diachronic evolution of the ALCAPA region. Major vertical movements post-dating nappe imbrication and metamorphism sta rted first in the Tisza-Dacia related orogenic compartments (East-, South C arpathians and Apuseni Mts.) as early as Late Aptian, whereas exhumation an d subsequent cooling of metamorphic crust in the East Alpine-West Carpathia n domain occurs from the Cenomanian onward. This characteristic basement-basin relationship suggests a strong coupling between lithospheric and surface processes, largely controlled by the rheol ogy of the orogenic system. Formation of internal Gosau basins is seen in c ontext with collapse of thickened and gravitationally unstable continental crust. (C) 1999 Elsevier Science Ltd. All rights reserved.