Syn- and post-orogenic exhumation of metamorphic rocks in North Aegean
R. Lacassin 1, N. Arnaud 2, P. H. Leloup 3, R. Armijo 1, and B. Meyer 4.
1: Institut de Physique du Globe de Paris, UMR7174 CNRS, Paris, France
2: Lab. Dynamique de la Lithosph`ere, UMR 5573 CNRS, USTL, Montpellier, France
3: Lab. Sciences de la Terre, UMR5570 CNRS, UCB Lyon, France
4: Lab. Tectonique, UMR7072 CNRS, Univ. P. et M. Curie, Paris, France
Abstract: 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.
Earth, 2, 51–63, 2007
www.electronic-earth.net/2/51/2007/
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link for the final edited version and the discussion (eArth site) |
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P.H. Leloup page |