“Comparative Petrogenetic Investigation of Composite Kaçkar Batholith Granitoids In Eastern Pontide Magmatic Arc- Northern Turkey.”


YILMAZ ŞAHİN S. , GÜNGÖR Y. , Boztuğ D.

Earth, Planet and Space, vol.56, pp.429-446, 2004 (Journal Indexed in SCI)

  • Publication Type: Article / Article
  • Volume: 56
  • Publication Date: 2004
  • Title of Journal : Earth, Planet and Space
  • Page Numbers: pp.429-446

Abstract

The Pontides are an east-west trending orogenic belt which is subdivided into west, middle and eastern sectors

according to their different tectonostratigraphy. The Eastern Pontides are represented by west-east-trending tectonic

zones resulted from a common Mesozoic-Tertiary history, comprises dominantly of magmatic rocks. The magmatic

belt in the Eastern Pontides includes a large batholith, termed the Composite Kac¸kar Batholith (CKB) in which there

are various granitic facies. The emplacement of CKB occurred in pulses between the Early Cretaceous and Eocene

period during the development of the eastern Pontide magmatic arc and following collisional events. The members

of the CKB are Dereli-S¸ ebinkarahisar (Giresun) in the west, southern Araklı (Trabzon) in the middle and Kac¸kar

Mountain and its surrounding area (Rize) in the east. The plutons ranging from syenite through monzonite to

granite are typically medium-high K calc-alkaline rarely tholeiitic and metaluminous I-type. The studied members

of the CKB intrudes into the Late Cretaceous arc volcanics and are determined to be Late Cretaceous-Eocene

(75

 

.7 ± 1.55; 41.2 ± 0.89) in K-Ar age. The tectono-magmatic setting of the granitoids has been interpreted as an

arc-related granitic suite, a post-collisional granitic suite and a post-orogenic granitic suite. Some plutons including

mafic magmatic enclaves (MME) and K-feldspar megacrystals suggest magma. mixing/mingling. HFS and LIL

element geochemistry of the granitic intrusions also suggest that fractional crystallization, magma mixing/mingling

and crustal contamination played an important role in the evolution of the CKB. All the data mentioned above

show that the granitoids in the three different regions may have been derived from an arc, developed in response to

the northward subduction of the northern branch of neo-Tethyan oceanic crust beneath the Eurasian plate in Late

Cretaceous and a collision between the Pontide arc and the Anatolide-Tauride platform in Paleocene.

Key words:

 

 

Granite, Turkey, arc magmatism, collision; Eastern Pontides.