Syn- and post-orogenic exhumation of metamorphic rocks in North Aegean

Robin Lacassin (1) , Nicolas Arnaud (2) , Philippe-Hervé Leloup (3) , Rolando Armijo (1) , Bertrand Meyer (4)

1 IPGP - Institut de Physique du Globe de Paris
2 LDL - Laboratoire Dynamique de la Lithosphère
3 LST - Laboratoire de Sciences de la Terre
4 LT - Laboratoire de tectonique

The Olympos-Ossa-Pelion (OOP) ranges, in NW Aegean, encompass Greece highest summit and are located near the extremity of the North Anatolian Fault (NAF). Structural and thermochronological data gathered in the OOP ranges show that the main exhumation of metamorphic nappes occurred in the Eocene, at ca. 43–39 Ma. This early exhumation, associated with ductile, then brittle-ductile normal faulting with northeastward transport, is coeval with orogenic shortening in the close area. Cooling rates, and likely exhumation, have been low between 40 Ma and 20 Ma. 40Ar/39Ar crystallization ages (between 20 and 15 Ma) appears related to brittle-ductile normal faulting and likely associated with Neogene Aegean back-arc extension. The dating of a diabase dyke, and the geometry of associated brittle jointing, of onshore and offshore active normal faults suggest a shift in extension direction after 4Ma, possibly in relation with the propagation of the NAF in northern Aegean.

Keywords: Tectonics; extension; orogeny; exhumation

Domains: Tectonics; Global Changes

Robin Lacassin, Nicolas Arnaud, Philippe-Hervé Leloup, Rolando Armijo, Bertrand Meyer. Syn- and post-orogenic exhumation of metamorphic rocks in North Aegean. eEarth, 2007, 2, pp.51-63. ⟨insu-00226378⟩