Tectonique quaternaire de la dépression d'Orava (Carpates occidentales) / Quaternary tectonics of the Orava Basin (Western Carpathians)

摘要

Abstract The fault-bounded Orava Basin was formed during the Neogene (Late Badenian to Pliocene) and enlarged during the Quaternary. It is a pull-apart basin filled with very fine-grained fluvial material reaching thickness of up to 930 m. Tectonic uplift in the Western Carpathians started in the Late Pliocene and affected the area of Orava Basin. Extensional activity manifested itself in the NE part of the present-day Orava Basin and the graben was filled with 112 m of Quaternary fluvial and glacio-fluvial deposits. The analysis of Quaternary terraces indicates that the SWpart of the Orava Basin floor was uplifted and dissected, thereby generating a system of 6 cut- and-fill terraces. The NE part of the Orava Basin consists of the large fluvial and glacio-fluvial fan of the Czarny Dunajec River. The Late-Wistulian and Holocenefan is related to active subsidence. Seismic refraction and reflection profiles document E-W Quaternary graben and horst structures. Recent earthquakes confirm ongoing tectonic activity. The opening of the Orava Basin started at ca 14 Ma and was synchronous with the onset of the uplift of the Tatra crystalline massif from depths of 5 km according to fission track data.