Precise Ar-40/Ar-39 ages from the metamorphic sole of the Mersin ophiolite (southern Turkey)


Parlak O. , DELALOYE M.

TECTONOPHYSICS, cilt.301, ss.145-158, 1999 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The Mersin ophiolite is located on the southern flank of the E-W-trending central Tauride belt in Turkey. It is one of the Late Cretaceous Neotethyan oceanic lithospheric remnants. The Mersin ophiolite formed in a suprasubduction zone tectonic setting in southern Turkey at the beginning of the Late Cretaceous. The Mersin ophiolite is one of the best examples in Turkey in order to study reconstruction of ophiolite emplacement along the Alpine-Himalayan orogenic belt. Ar-40/Ar-39 incremental-heating measurements were performed on seven obduction-related subophiolitic metamorphic rocks. Hornblende separates yielded isochron ages ranging from 96.0 +/- 0.7 Ma to 91.6 +/- 0.3 Ma tall errors +/-1 sigma). Five of the seven hornblende age determinations are indistinguishable at the 95% confidence level and have a weighted mean age of 92.6 +/- 0.2 (2 sigma) Ma. We interpret these ages as the date of cooling below 500 degrees C. Intraoceanic thrusting occurred (similar to 4 Ma) soon after formation of oceanic crust, The sole was crosscut by microgabbro-diabase dikes less than 3 m.y. later The final obduction onto the Tauride platform occurred during the Late Cretaceous-Early Paleocene. Our new high-precision ages constrain intraoceanic thrusting for a single ophiolite (Mersin) in the Tauride belt. (C) 1999 Elsevier Science B.V. All rights reserved.