Nature and significance of Late Cretaceous ophiolitic rocks and their relation to the Baskil granitic intrusions of the Elazig region, SE Turkey


Rizaoglu T., PARLAK O. , Hoeck V., İŞLER F.

TECTONIC DEVELOPMENT OF THE EASTERN MEDITERRANEAN REGION, cilt.260, ss.327-350, 2006 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 260
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1144/gsl.sp.2006.260.01.14
  • Dergi Adı: TECTONIC DEVELOPMENT OF THE EASTERN MEDITERRANEAN REGION
  • Sayfa Sayıları: ss.327-350

Özet

The Elazig region in SE Turkey comprises, in descending order, the Palaeozoic-Mesozoic Malatya-Keban platform, an ensimatic island arc unit (i.e. Elazig magmatic rocks-Yuksekova complex), and ophiolitic rocks (i.e. Komurhan) of Late Cretaceous age. All of these were intruded by the Baskil granitic rocks. These tectonomagmatic-stratigraphic assemblages were emplaced over the Middle Eocene volcano-sedimentary Maden complex to the south during the evolution of the SE Anatolian orogen. The Komurhan ophiolite exhibits an intact ophiolite pseudostratigraphy. The base of this has been metamorphosed to amphibolite facies during intraoceanic subduction-thrusting. The amphibolitic rocks were intruded by synkinematic granitic rocks (Baskil magmatic rocks). The ensimatic island arc volcanic rocks are widely distributed in the region. The contact of the volcano-sedimentary unit with the underlying Komurhan ophiolite is a thrust dipping to the north. The rock assemblages of the volcano-sedimentary unit suggest formation of small volcanic edifices above a subduction zone, coupled with debris-flow deposits and volcaniclastic turbidites. The whole-rock and mineral chemistry of the Komurhan ophiolite and the ensimatic island arc volcanic rocks suggests that they represent a comagmatic tholeiitic suite, formed in the Late Cretaceous in a suprasubduction zone (SSZ) setting. The amphibolites beneath the Komurhan ophiolite indicate derivation from an island arc tholeiite (IAT) protolith. The geological and geochemical evidence from the Elazig region suggests the following evolutionary scenario. The Komurhan ophiolite was formed above a north-dipping subduction zone between the Arabian platform to the south and the Tauride platform to the north in Late Cretaceous (c. 90 Ma). An ensimatic island arc assemblage was then built on the SSZ-type crust. The metamorphic sole was formed by metamorphism of IAT-type basalts that were detached from the front of the overriding Komurhan ophiolite and then underplated. These units were then accreted to the base of the Tauride active margin to the north, where both units were cut by the Baskil granitic rocks around 85 Ma.