New zircon U-Pb LA-ICP-MS ages and Hf isotope data from the Central Pontides (Turkey): Geological and geodynamic constraints
Abstract
The Central Pontides in northern Anatolia is located on the accretionary complex formed by the closure of Neotethyan Intra-Pontide Ocean between the southern Eurasian margin (Istanbul-Zonguldak Terrane) and the Cimmerian Sakarya Composite Terrane. Among other components of the oceanic lithosphere, it comprises not yet well-dated felsic igneous rocks formed in arc-basin as well as continent margin settings. In-situ U-Pb age results for zircons from the arc-basin system (öangaldağ Metamorphic Complex) and the continental arc (Devrekani Metadiorite and Granitoid) yield ages of 176 ± 6 Ma, 163 ± 9 Ma and 165 ± 3 Ma, respectively. Corresponding in-situ average (initial) 176Hf/177Hf initial ratios are 0.28261 ± 0.00003, 0.28267 ± 0.00002 and 0.28290 ± 0.00004 for these units and indicative of a subduction-modified mantle source. The new U-Pb ages and Hf isotope data from these oceanic and continental arc units together with regional geological constraints support the presence of a multiple subduction system within the Intra-Pontide Ocean during the Middle Jurassic.
- Publication:
-
Journal of Geodynamics
- Pub Date:
- May 2018
- DOI:
- 10.1016/j.jog.2018.01.004
- Bibcode:
- 2018JGeo..116...23C
- Keywords:
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- Intra-Pontide ocean;
- Jurassic;
- Arc magmatism;
- Central Pontides;
- N Turkey