Akademik Veri Yönetim Sistemi
GEOLOGICAL MAGAZINE, cilt.142, sa.2, ss.187-207, 2005 (SCI-Expanded)
Collision-related rocks intrude metamorphic rocks overthrust by ophiolitic units to make up the Central Anatolian Crystalline Complex. A wide variety of rock types were produced by the latest Cretaceous magmatism in the complex. These rocks can be divided into three distinct units: (1) calc-alkaline (Agacoren, Behrekdag, Cefalikdag, Celebi, Ekecikdag, Halacli, Karamadazi, Kosefakili, Terlemez, Uckapili, Yozgat); (2) sub-alkaline (Baranadag); and (3) alkaline (Atdere, Davulalan, Egrialan, Hamit, Idisdagi, Karacayir). The calc-alkaline rocks are metaluminous/peraluminous I- to S-type plutons ranging from monzodiorite to granite. The sub-alkaline rocks are metaluminous I-type plutons ranging from monzonite to granite. The alkaline rocks are metaluminous to peralkaline plutons, predominantly A-type, ranging from foid-bearing monzosyenite to granite. These plutons crystallized under varying pressures (5.3-2.6 kbar) and a wide range of temperatures (858-698 degrees C) from highly oxidized magmas (log f O-2 -17 to - 12). All intrusive rocks display enrichment in LILE and LREE compare to HFSE and have high Sr-87/Sr-86 and low Nd-143/Nd-144 ratios. These characteristics indicate that these rocks are derived from a mantle source containing large subduction components, and have experienced assimilation coupled with fractional crystallization (AFC) during uprise through crust. The coexistence of cale-alkaline and alkaline magmatism in the complex may be ascribed to mantle source heterogeneity before collision. Either thermal perturbation of the metasomatized lithosphere by delamination of the thermal boundary layer or removal of a subducted plate (slab breakoff) are the likely mechanisms for the initiation of the collision-related magmatism in the complex.