Motion at the junction of the Dinarides and Hellenides in light of new thermochronological ages (northern Albania, Kosovo and Montenegro)

Résumé fourni par la source

The timing of motion at the junction of the Dinarides and Hellenides is constrained by combining low-temperature thermochronology (ZFT, ZHe and AFT), RSCM estimates of peak temperature (Tp) and sedimentary ages near the Shkoder-Peja Normal Fault (SPNF). ZFT and ZHe ages constrain cooling of the West Vardar Ophiolite and its underlying mélange from Tp of 238-337°C in Early Cretaceous time (103-108 Ma), well after latest Jurassic to earliest Cretaceous obduction onto the Adriatic passive margin. Fragments of the margin beneath the mélange experienced upper greenschist-facies mylonitization. Subsequent accretion of the Adriatic margin involved SW-directed Dinaric nappe stacking and post-nappe folding (Tp of 183-221°C) between 46-49 Ma as constrained by ZHe cooling ages. Higher RSCM temperatures (300-460°C) are restricted to Middle Triassic granitoids yielding scattered Cretaceous ZFT and ZHe ages. These reflect the precipitation of carbonaceous matter during post-intrusive fluid activity. Orogen-parallel extension along the SPNF was accompanied in its footwall by doming and mylonitic overprinting of the Dinaric folds. ZHe and AFT ages bracket the SPNF’s age at 48 and 21 Ma. Within this range, a Late Oligocene-to-Miocene age is favored on stratigraphic grounds. Continued extension involved cataclastic overprinting along the SPNF and Mid-Miocene to Pliocene (16-5 Ma) sedimentation in the Metohia-Dukagjini Basin. Subsequent extension in Plio-Pleistocene time (5-3 Ma) migrated into the southern part of this basin. The SPNF is part of a system of Neogene normal faults that continues to accommodate clockwise arcuation and attenuation of the Dinaric-Hellenic chain in response to slab tearing and Hellenic roll-back subduction.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.