Origin and geodynamic environments of the metamorphic sole rocks from the zmir-Ankara-Erzincan suture zone (Tokat, northern Turkey)


CORTUK R. M. , ÇELİK Ö. F. , OZKAN M., SHERLOCK S. C. , MARZOLI A., ALTINTAŞ İ. E. , et al.

INTERNATIONAL GEOLOGY REVIEW, cilt.58, ss.1839-1855, 2016 (SCI İndekslerine Giren Dergi)

  • Cilt numarası: 58 Konu: 15
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1080/00206814.2016.1181991
  • Dergi Adı: INTERNATIONAL GEOLOGY REVIEW
  • Sayfa Sayısı: ss.1839-1855

Özet

The Late Cretaceous accretionary complex of the zmir-Ankara-Erzincan suture zone, near Artova, is composed mainly of peridotites (variably serpentinized), amphibolite, garnet-micaschist, calc-schist, marble, basalt, sandstones, neritic limestones. The metamorphic rocks were interpreted as the metamorphic sole rocks occurring at the base of mantle tectonites, because: (i) amphibolites were observed together with the serpentinized peridotites suggesting their occurrences in the oceanic environment; (ii) foliation in amphibolites and serpentinized peridotites run subparallel to each other; (iii) all these metamorphic rocks and serpentinized peridotites are cross-cut by the unmetamorphosed dolerite dikes with island arc tholeiite-like chemistry. Geochemical characteristics of the amphibolites display enriched mid-ocean ridge basalt (E-MORB)- and ocean island basalt (OIB)-like signatures. The dolerite dikes, on the other hand, yield an island arc tholeiite-like composition. Geothermobarometric investigations of the metamorphic sole rocks suggest that the metamorphic temperature was similar to 650 +/- 30 degrees C and the pressure condition was less than 0.5GPa. Dating of hornblende grains from amphibolite yielded age values ranging from 139 +/- 11 to 157 +/- 3.6Ma (2 sigma). The oldest weighted average age value is regarded as approximating the timing of the intra-oceanic subduction. These cooling ages were interpreted to be the intra-oceanic subduction/thrusting time of the zmir-Ankara-Erzincan oceanic domain.