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Turkish Journal of Earth Sciences

DOI

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Abstract

The Karamadazı Granitoid (Yahyalı-Kayseri) is a typical example of bimodal magmatism on the northern margin of the Eastern Tauride belt. The Karamadazı Granitoid intrudes the Palaeozoic-Mesozoic Yahyalı metamorphic rocks and is unconformably overlain by Upper Maastrichtian clastics. It consists of granodiorite-quartz diorite as the main intrusive phase, and includes leucogranites and aplitic dykes in its marginal parts. Samples from the Karamadazı Granitoid are calc-alkaline and calcic in character. The granodiorites are mainly metaluminous, whereas leucogranites and aplites are weakly peraluminous in nature. Plots of major-element oxides against SiO2 indicate a poor fractionation trend for the granodiorites. The leucogranites represent highly fractionated end-members. The Karamadazı Granitoid displays I-type characteristics based on geochemical and mineralogical compositions. LIL elements are enriched compared to the HFS elements and spider-diagram patterns are similar to those of upper continental crust rocks. The geochemical data also imply that the Karamadazı Granitoid is composed of two distinct magmas, derived from different sources that have undergone limited differentiation. Whatever the sources were, the magmas have interacted with the upper continental crust. On tectono-magmatic discrimination diagrams, the granodiorites plot in the arc region, while leucogranites plot in the triple-junction of the arc, syn-collisional and within-plate fields and thus can be classified as post-collisional granitoids. Geochemical comparison of the Karamadazı Granitoid with several H-type post-collisional granitoids from the northern Tauride margin (Horoz Granitoid) and central Anatolia (Yozgat, Ekecikdağ, and Terlemez granitoids) indicates clear similarities among these granitoids. This suggests that the granitoids are comparable not only in age, formation and emplacement processes, but also in the tectonic processes which led to their formation.

Keywords

Karamadazı Granitoid, Geochemistry, Granodiorite, Leucogranite, Eastern Tauride Belt, Central Turkey

First Page

103

Last Page

119

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