Resumen de A «mini-orogen» mirrored in detrital apatite FT ages of Alpine Miocene Molasse - The obscure Post-Gosau cooling event of the Eastern Alps

Istvan Dunkl, W. Frisch, J. Kuhlemann

• The post-Variscan mica K/Ar, Ar/Ar and Rb/Sr ages o f the Eastern Alps form two definite clusters: a Late Cretaceous and a Neogene one. These ages mark well the main periods o f the Alpine deformation and cooling.

  From the Paleogene we have a rather limited record. Only mica cooling ages are known from the Penninic windows, from their immediate vicinity andfrom the Periadriatic lineament (Läufer, et al., 1997; Handler et al., 2000; Müller et al., 1996). The scarcity o f data indicates the lack o f exhumation o f huge rock masses, and thus, gives a limit on the paleo-relief during the Paleogene times. However, paleogeographic and structural considerations suggest that a part o f the Eastern Alps was folded, exhumed and supplied siiic ¡clastic material into the surrounding basins (Oberhäuser, 1980). For the detection ofshallow erosion the apatite fission track (FT) thermochronology is a well accepted and useful method. However, the Neogene exhumation resulted in a high relief and as a consequence o f it the deep erosion frequently removed the topmost level with the thermochronologic record o f the pre-Neogene events