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

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. 40Ar/39Ar 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 (all errors ±1?). 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?) Ma. We interpret these ages as the date of cooling below 500°C. Intraoceanic thrusting occurred (~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.20-40240.94/1 Université de Genève: 21-37449.93This work is supported by the Swiss National Science Foundation Grant (20-40240.94/1). The University of Geneva 40 Ar/ 39 Ar Geochronology Laboratory was constructed in part with funds from the Swiss National Science Foundation grant (21-37449.93). Dr. Bradly Singer is greatly acknowledged for his help during the measurements and for his suggestions for the early version of the paper. Ö. Faruk Celik is acknowledged for his field assistance. We thank Edwin Gnos, Partick Monie and Jean-Pierre Burg for their critical and constructive reviews of the paper. Appendix