Contemporaneous late cretaceous calc-alkaline and alkaline magmatism in Central Anatolia, Turkey: Oxygen isotope constraints on petrogenesis

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İLBEYLİ N., Pearce J. A., Meighan I. G., Fallick A. E.

Turkish Journal of Earth Sciences, vol.18, no.4, pp.529-547, 2009 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 18 Issue: 4
  • Publication Date: 2009
  • Doi Number: 10.3906/yer-0811-8
  • Journal Name: Turkish Journal of Earth Sciences
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.529-547
  • Keywords: A-type granite, Central Anatolia, I-type granite, Kaman-Ki{dotless}rşehir region, Oxygen isotope, Turkey
  • Hatay Mustafa Kemal University Affiliated: No

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 δ18O values between 6.5‰ and 14.8‰. Initial 87Sr/86Sr versus 143Nd/144Nd ratios, and both ratios versus δ18O 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. © Tübi̇tak.