Contemporaneous Late Cretaceous Calc-alkaline and Alkaline Magmatism in Central Anatolia, Turkey: O Isotope Constraints on Petrogenesis

Authors : Mustafa Kemal University, İskenderun Campus, Faculty of Engineering, TR

Pages : 529-547

Doi:10.3906/sag-1204-81

View : 12 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :A wide variety of rock types were produced by the latest Cretaceous magmatism in the Central Anatolian Crystalline Complex. These rocks can be divided into three distinct units: insert ignore into journalissuearticles values(i); calc-alkaline, insert ignore into journalissuearticles values(ii); subalkaline/transitional, and insert ignore into journalissuearticles values(iii); alkaline. The calc-alkaline rocks are mainly metaluminous insert ignore into journalissuearticles values(I-type); ranging from monzodiorite to granite. The subalkaline/transitional rocks are also metaluminous insert ignore into journalissuearticles values(I-type); ranging from monzonite to granite. The alkaline rocks are mainly peralkaline insert ignore into journalissuearticles values(A-type);, ranging from feldspathoid-bearing monzosyenite to granite. Whole-rock oxygen isotope data from the complex have a considerable range of d18O values between 6.5 per thousand and 14.8 per thousand. Initial 87Sr/86Sr versus 143Nd/144Nd ratios, and both ratios versus d18O values diagrams show that the intrusive rocks are derived from a subduction-modified mantle and also have experienced fractional crystallisation coupled with crustal assimilation. Delamination of a thermal boundary layer, and/or slab breakoff is the likely mechanisms for the initiation of the diverse magmatism in the complex.
Keywords : I type granite, A type granite, oxygen isotope, Kaman Kırşehir region, central Anatolia, Turkey