Central Taurides Research Articles

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 ±1σ). 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 (2σ) 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.

Geochemistry and timing of post‐metamorphic dyke emplacement in the Mersin Ophiolite (southern Turkey): New age constraints from 40Ar/39Ar geochronology

ABSTRACTThe Mersin ophiolite, which is a relic of the late Cretaceous Neotethyan ocean domain in the eastern Mediterranean, is situated on the southern flank of the central Tauride belt. The ophiolite body is cross‐cut at all structural levels by numerous mafic dyke intrusions. The dykes do not intrude the underlying melange of platform carbonates. Therefore, dyke emplacement post‐dates the formation of the opholite and metamorphic sole but pre‐dates the final obduction onto the Tauride platform. The post‐metamorphic dyke swarms suggest the geochemical characteristics of Island Arc Tholeiites (IAT). 40Ar/39Ar geochronology of the post‐metamorphic microgabbroic‐diabasic dykes cutting both mantle tectonites and metamorphic sole revealed ages ranging from 89.6 ± 0.7–63.8 ± 0.9 Myr old, respectively, indicating widespread magmatic activity during the Late Cretaceous‐early Palaeocene in the Neotethyan ocean. These data suggest that island arc development in the Neotethyan ocean in southern Turkey was as early as Late Cretaceous.

The Obduction Direction of the Mersin Ophiolite: Structural Evidence from Subophiolitic Metamorphics in the Central Tauride Belt, Southern Turkey

The Mersin ophiolite is an ∼6-km-thick oceanic crustal sequence in the central Taurides (southern Turkey), forming large outcrops on the southern flank of Bolkardag. It comprises a sequence of units and includes, in ascending structural order, the Mersin melange, subophiolitic metamorphics, tectonics, ultramafic and mafic cumulates, and pillow lavas interlayered with deep-marine sediments. Thin beds of ophiolite-related metamorphics occupy a constant stratigraphic position at the base of the thick ultramafic unit and include a characteristic rock association of amphibolite and amphibolitic schist, epidote-amphibole schist, quartz-mica schist, calcschist, and marble, which exhibits a typical inverted metamorphic zonation from upper amphibolite to greenschist facies. The protoliths of these metamorphics are oceanic-island basaltic rocks and associated pelagic sediments. They are cut by a swarm of approximately E-W-trending, post-metamorphic, MORB-type tholeiite, microgabbroic-diabasic dikes, which are seen ...