GEOCHEMISTRY OF VERCENIK MOUNTAIN (RIZE) GRANITOIDS IN EASTERN PONTIDE IGNEOUS TERRANE, TURKEY: CONSTRAINS ON I-TYPE, HYBRIDE MAGMATISM

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 1, 57 - 74 pp

ABSTRACT

The outcropping granitoids in the Eastern Pontides, ranging from upper Cretaceous to
Eocene in age, consisting of various intrusive rock units, have been defined as the
composite Kaçkar Batholith. These rock units showing a high variety from granites
through syenite and even to gabbros in composition are the plutonic equivalents of the
Eastern Pontide Magmatism. This variety in both of the composition and age
accompanies with a wide spectrum in genesis, from arc through collision and even to
post-collisional within plate magmatism. The subunits of granitoids, The Ortaköy quartz
monzonite, Kumlagölü monzogranite and Leğenderesi micro granite, outcropping in the
southern parts of the Kaçkar Batholith, the north of Verçenik Mountain, are the products
of a K-rich calcalkaline, mostly metaluminous characterized, excessively continental
crust contaminated, I-typed, and hybrid magma source’s differentiation. According to
some the HFSE, LILE and REE geochemistry data, such a single and hybrid magma is
asserted to have a post-collisional genesis related to certain processes, like fractional
crystallization and magma mixing. Late and post magmatic stages were dominated by
strong hydrothermal activity. Granitoids of the studied area may be related to the
igneous activity of the extensional regime in Eocene, after the collision of Anatolide –
Pontide platforms, during a term of the well-known arc magmatism.

Keywords: Post-collisional magmatism, Eastern Pontides, HFS, LIL elements,
fractional crystallization, magma mixing/mingling.