Subduction/obduction processes prior to collision: records from the Tavsanli zone (western Turkey)
Abstract
The tectono-metamorphic evolution of the ~80Ma high-pressure low-temperature (HP-LT) Tavsanli zone (Western Anatolia, Izmir-Ankara suture zone) is herein reappraised to highlight processes occurring along a fossil subduction interface, from initial intra-oceanic subduction to continental subduction and soft collision. Structural and petrological data allow in particular (i) to constrain the nature, internal structure and PT conditions of the oceanic accreted oceanic unit sandwiched between the continental Orhaneli unit and the non-metamorphic obducted ophiolite on top; (ii) to revaluate the peak-pressure conditions for the subducted northern margin of the Anatolide-Tauride Block (the Orhaneli unit). In the ocean slices, two distinct, extensive oceanic complexes (OC1 and OC2) are recognised on top of one another, incipient HP-LT imprint (OC1) to blueschist facies conditions (OC2). Based on the first occurrence of Fe-Mg carpholite and on pseudosection calculations, PT estimates of 250-350°C and 11-13 kbar are inferred for OC2. The internal structure of the accretionary complex points to the underplating of kilometre-scale units at different depths along the plate interface and to contrasting dynamics with respect to both the underlying continental unit and the ophiolite. PT conditions for the continental Orhaneli unit are reappraised at 22 kbar and 500°C using both Raman spectroscopy on carbonaceous matter and pseudosection modelling and are similar to PT conditions known for the leading edge of the continental Arabian margin in Oman. Inter-plate mechanical coupling within the Tavsanli zone is finally compared to the Oman case to shed light on regional scale tectonics, accretionary dynamics and (rapid) thermal reequilibration of the subduction interface.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.T11A2426P
- Keywords:
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- 8170 TECTONOPHYSICS Subduction zone processes;
- 3613 MINERALOGY AND PETROLOGY Subduction zone processes