1 Introduction The Central Anatolia region, variously called the Central Anatolian Massif (Ketin, 1955), Kırşehir Crystalline Massif (Seymen, 1982), Kırşehir Block (Şengör, 1984), Kırşehir Massif (Erler et al., 1991) and Central Anatolian Crystalline Complex (Göncüoğlu et al., 1991), consists of an assemblage of magmatic and metamorphic rocks outcropping in a triangular area. The numerous Late Cretaceous granitoid plutons occur in the Central Anatolia (Turkey), and are interpreted as resulting from syn- to post-collisional tectonics related to the closure of the Neotethys ocean (Köksal et al., 2012, and reference therein). Located in the southern part of the Kırşehir Massif, the Late Cretaceous Üçkapılı granitoid is one of the intrusive suites in the Central Anatolia. The age and petrogenesis of the Üçkapılı granitoid have been studied by few researches, and the rocks were interpreted as crustal-derived melts (Göncüoğlu, 1986; Whitney et al., 2003). Although previous studies provided good age and petrological data from the granitoid, they lacked information on enclaves of the granitoid. This study focuses on both the Üçkapılı granitoid and its mafic enclaves to constrain their origins. For this purpose, we present new data of mineral chemistry and whole rock geochemistry (major, trace and rare earth elements, and 87 Sr/ 86 Sr- 143 Nd/ 144 Nd isotopes). Our findings indicate that the Üçkapılı granitoid is H-(hybrid) type granitoid developed by mixing/mingling processes between crustal melts and mantle-derived mafic magmas. 2 Geological Setting and Stratigraphy The study area is located to northeast of Niğde, Central Anatolia (Turkey). The region belongs to the Kırşehir Massif which is surrounded by the suture zones developed as a result of the closure of various branches of Neotethys (Fig. 1a). The basement in the Central Anatolia comprises pre-Mesozoic metamorphic rocks consisting of a complex of amphibolites, gneisses, schists, calc-schists, phyllites and marbles. The metamorphic rocks are tectonically overlain by Mesozoic ophiolitic melanges representing the remnants of Neotethyan ocean floor (Şengör and Yılmaz, Petrogenesis of the Üçkapılı Granitoid and its Mafic Enclaves in Elmalı Area (Niğde, Central Anatolia, Turkey) Hüseyin KURT 1,* , Kerim KOÇAK 1 , Kürşad ASAN 1 and Mustafa KARAKAŞ 2 1 Department of Geological Engineering, Selçuk University, 42079, Konya, Turkey 2 Central Anatolia Directorate of Mineral Research and Exploration, Konya, Turkey Abstract: The Late Cretaceous Üçkapılı Granitoid including mafic microgranular enclaves intruded into metapelitic and metabasic rocks, and overlain unconformably by Neogene ignimbrites in the Niğde area of Turkey. It is mostly granite and minor granodiorite in composition, whereas its enclaves are dominantly gabbro with a few diorites in composition. The Üçkapılı Granitoid is composed mainly of quartz, K-feldspar, plagioclase, biotite, muscovite and minor amphibole while its enclaves contain mostly plagioclase, amphibole, minor pyroxene and biotite. The Üçkapılı Granitoid has calcalkaline and peraluminous (A/CNK= 1.0–1.3) geochemical characteristics. It is characterized by high LILE/HFSE and LREE/HREE ratios ((La/Lu) N = 3–33), and has negative Ba, Ta, Nb and Eu anomalies, resembling those of collision granitoids. The Üçkapılı Granitoid has relatively high 87 Sr/ 86 Sr (i) ratios (0.711189–0.716061) and low εNd (t) values (-5.13 to -7.13), confirming crustal melting. In contrast, the enclaves are tholeiitic and metaluminous, and slightly enriched in LILEs (K, Rb) and Th, and have negative Ta, Nb and Ti anomalies; propose that they were derived from a subduction-modified mantle source. Based on mineral and whole rock chemistry data, the Üçkapılı granitoid is H-(hybrid) type, post-collision granitoid developed by mixing/mingling processes between crustal melts and mantle-derived mafic magmas. Key words: H-type granitoid, mafic enclave, geochemistry, Central Anatolia, Turkey Vol. 87 No. 3 pp.801–840 ACTA GEOLOGICA SINICA (English Edition) June 2013 2013-5-21打印 * Corresponding author. E-mail: hkurt@selcuk.edu.tr 完成作者一校并发出二校