From gondwana rifting to alpine orogeny

Ali Mohammadi (1) , Jonas Ruh (2) , Marcel Guillong (2) , Oscar Laurent (3, 2) , Lotfollah Aghajari

1 ITÜ - Istanbul Technical University
2 D-ERDW - Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich]
3 GET - Géosciences Environnement Toulouse

The Kopet Dagh mountains in NE Iran exhibit a 7-km-thick continuous sedimentary sequence recording detritus from exposed surrounding terranes from the last 175 Myr. This work presents a multidisciplinary geochronologic and provenance analysis in an attempt to identify and date major geologic events along the northern segment of the Tethys and reconstruct the regional tectonic history from Gondwana-related rifting until Alpine orogeny. Sandstone framework, heavy mineral analysis, U-Pb dating of detrital zircons, and Hf-isotope ratio measurements on dated zircons from Triassic to Paleocene sandstones indicate three main tectonic events that include early Silurian intracontinental rifting (opening of Paleo-Tethys), early Carboniferous rifting of a back-arc basin (Aghdarband Basin), and Late Triassic collisional to post-collisional magmatism(Paleo-Tethys collision). Mineralogical and age peak considerations indicate that detritus was supplied from the south into the extensional Kopet Dagh Basin during Middle Jurassic, while Cretaceous to Paleocene sandstones show signs of increasing cannibalism.

Mots clés: Gondwana; Kopet Dagh Basin; Paleo-Tethys; Neo-Tethys; Rifting; Collision; Detrital zircon; Hf isotopes; Provenance anlysis

Domaines: Sciences de la Terre; Géochimie; Pétrographie; Volcanologie

Ali Mohammadi, Jonas Ruh, Marcel Guillong, Oscar Laurent, Lotfollah Aghajari. From gondwana rifting to alpine orogeny. American journal of science, 2022, 322 (4), pp.561-592. ⟨10.2475/04.2022.02⟩. ⟨hal-03864243⟩