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

Authors

NURDANE İLBEYLİ
JULIAN A. PEARCE
IAN G. MEIGHAN
ANTHONY E. FALLICK

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: (i) calc-alkaline, (ii) subalkaline/transitional, and (iii) alkaline. The calc-alkaline rocks are mainly metaluminous (I-type) ranging from monzodiorite to granite. The subalkaline/transitional rocks are also metaluminous (I-type) ranging from monzonite to granite. The alkaline rocks are mainly peralkaline (A-type), ranging from feldspathoid-bearing monzosyenite to granite. Whole-rock oxygen isotope data from the complex have a considerable range of \delta18O values between 6.5 per thousand and 14.8 per thousand. Initial 87Sr/86Sr versus 143Nd/144Nd ratios, and both ratios versus \delta18O 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.

DOI

10.3906/yer-0811-8

Keywords

I-type granite, A-type granite, oxygen isotope, Kaman-Kırşehir region, central Anatolia, Turkey

First Page

529

Last Page

547

Recommended Citation

İLBEYLİ, NURDANE; PEARCE, JULIAN A.; MEIGHAN, IAN G.; and FALLICK, ANTHONY E. (2009) "Contemporaneous Late Cretaceous Calc-alkaline and Alkaline Magmatism in Central Anatolia, Turkey: O Isotope Constraints on Petrogenesis," Turkish Journal of Earth Sciences: Vol. 18: No. 4, Article 3. https://doi.org/10.3906/yer-0811-8
Available at: https://journals.tubitak.gov.tr/earth/vol18/iss4/3