The timing of polyphase Miocene tectonics in Northern Romania

Abstract

This study addresses the polyphase Miocene tectonic evolution in the Maramures area (northern Romania) by combining field observations, stratigraphic arguments and fission-track analysis (Tischler et al. in press). Fission-track analysis has been carried out on basement samples from the Rodna horst, situated in the East Carpathians (Bucovinvian nappes). This area was affected by Cretaceous medium- to low-grade metamorphism, followed by post-collisional exhumation and renewed moderate thermal overprint due to the deposition of Eocene to Early Miocene sediments. Based on paleostress analyses of mesoscale structures, three main tectonic phases can be disdinguished in the study area, all of which are postdate the earliest Miocene (Aquitanian, 20.5 Ma). In late Early Miocene (Burdigalian) the Pienide nappes, nonmetamorphic flysch series, were emplaced onto the Paleogene to Early Miocene sedimentary cover of the Bucovinian nappes...