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Öğe Characteristics of the amphibolites from Nigde metamorphics (Central Turkey), deduced from whole rock and mineral chemistry(GEOCHEMICAL SOC JAPAN, 2007) Kocak, Kerim; Kurt, Huseyin; Zedef, Veysel; Ferre, Eric C.Whole rock and mineral chemistry of amphibolites are presented for the lower (Gumusler Formation) and higher parts (Kaleboynu Formation) of the Nigde Massif with the aim to constrain protolith genesis and metamorphic P-T-conditions. The amphibolites, associated with a series of supracrustal metasediments, as thin layers and discontinuous pod/small lenses, are of igneous origin with composition of subalkaline and tholefitic basalts. Based on immobile elements content and ratios, amphibolites from both formations are thought to have formed mostly by fractional crystallisation of pyroxene +/- spinel, amphibole, plagioclase as well as apatite and titanite; coupled with minor crustal contamination. Contamination is particularly clear for the Gumusler Formation formed in a back-arc basin (Paleothetys) during magmatic ascent through the thickened Central Anatolian crust. The basic rocks could have been metamorphosed later at 7.5-3 +/- 0.6 kb and 850-420 degrees C, with the temperature gradient ranging from 35 to 122 degrees C/km at different depths in the Neo-Tethyan subduction zone, and exhumed from depths of approximately 20 km via regional extension.Öğe Constraints on the Age of Metasediments from the Western Part (Ortakoy, Aksaray) of the Central Anatolian Crystalline Complex, Turkey(SPRINGER INT PUBLISHING AG, 2014) Kocak, KerimThe Central Anatolian Crystalline Complex (CACC) is the largest metamorphic domain, a similar to 300 9 200 km triangular region, exposed in Turkey. The basement is composed mainly of migmatites, paragneisses, alternations of marble and paragneiss, and a thick metacarbonate sequence. The sequence in the area starts with graphite-bearing paragneiss with interlayers of marble, and metabasics (Tamadag Formation), and continues with marble containing paragneiss, and rare metabasics (Bozcaldag. Formation). The basement is overlain by Cretaceous ophiolites, which are cut by voluminous Late Cretaceous-Palaeocene granitoids. Neogene formations complete the rock sequence in the area. The first certain macrofossil, Heliolitinae (Heliolitidae fam.) Paeckelmannophora sp., has been discovered in the marble of the Tamadag Formation. Also found are Acritarchs Leiosphaeridia sp. and Lophosphaeriduim sp. together with possible graptolite fragments (questionably of Retiolites sp.) in the marble residue obtained by treatment with acetic acid. Paeckelmannophora sp. and fragments of Retiolites sp. have been found, pointing to a Silurian-Devonian age. The Bozdag Formation, overlying conformably the Tamadag Formation, could hence be late Palaeozoic in age. Based on the age of the metasediments and the geochemistry of the amphibolites in the Nigde Massif, it has been suggested that the CACC could have undergone Hercynian metamorphism, whose effects may have been destroyed by intensive polyphase Alpine metamorphism. The Tamadag Formation may be correlated with the Silurian-lower Carboniferous Bozdag Formation of the Konya Complex (Afyon-Bolkardag. Zone), 200 km WSW of the study area.Öğe Effect of salt crystallization on stones of historical buildings and monuments, Konya, Central Turkey(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Zedef, Veysel; Kocak, Kerim; Doyen, Adnan; Ozsen, Hakan; Kekec, BlIgehanIn this study, we investigated the chemical and physical properties of the volcanic rocks used as building stones in historical places and monuments. The chemical weathering effect of salt crystallization on these stones was measured on the laboratory conditions (in most cases, used samples were very small). For this purpose, the dry weight loss (DWL) test was conducted. The rocks of dacite, andesite and tuffs of volcanic origin have different durability against salt crystallization. The most stable rocks are dacites (DWL 2.06%) which were used in the construction of Hittite monuments at Eflatun. The durability of the stones is closely related to their chemical, mineralogical, petrographical and mechanical properties. The stones used in the historical buildings are generally much more stable than present-day building stones. (c) 2005 Elsevier Ltd. All rights reserved.Öğe GEOCHEMICAL AND PETROLOGICAL FEATURES OF THE PRECAMBRIAN METAMAFIC ROCKS IN MUTKI (BITLIS MASSIF) AREA, SE-TURKEY(INT SCIENTIFIC CONFERENCE SGEM, 2009) Kocak, Kerim; Ceran, Fatih M.The metamafic rocks are represented by amphibolite, garnet-bearing amphibolite and amphibole-bearing schists, associated with a series of supracrustal metasediments in Pan-African basement of the Bitlis massif. The geochemical data of the samples propose different igneous protolithes varying from calcalkaline basalt to andezite. The samples can be classified as Group-1(low Zr) and Group-2 (high Zr), all displaying various enrichments in large ion lithophile (LIL) and light rare earth (LRE) elements and depletion in high field strength (HFS) elements. High LILE/HFSE and LREE/HREE ratios, a variety of tectonomagmatic diagrams offer clearly a destructive plate margin geotectonic setting for the samples. The metamafic rocks are suggested to have formed mostly by fractional crystallization of plagioclase, apatite and titaniferous magnetite +/- olivine +/- clinopyroxene +/- amphibole; coupled with minor crustal contamination in relation with subduction-related magmatism neighboring the Andean-type active margins of Gondwana. The samples were then regionally metamorphosed at amphibolite facies conditions, between 540-610 degrees C at similar to 5 kb.Öğe Hybridization of mafic microgranular enclaves: mineral and whole-rock chemistry evidence from the Karamadazi Granitoid, Central Turkey(SPRINGER, 2006) Kocak, KerimOn the Eastern Tauride Belt, the Cretaceous calc-alkaline Karamadazi Granitoid consists of quartz diorite containing mafic microgranular enclaves (MME) and leucocratic granite. The quartz diorite consists of plagioclase (An(8-65)), hornblende, biotite, K-feldspar, quartz, epidote and titanite. Subrounded MME in the quartz diorite are holocrystalline, fine-grained, quartz diorite to diorite in composition, and display a similar mineral assemblage to their host. Large crystals in MME and quartz diorite show various disequilibrium microstructures indicative of hybridization. Plagioclase crystals exhibit inverse, normal, and oscillatory zoning with maximum core-to-rim An content increase up to 38% in the enclave and 40% in the quartz diorite. Both hornblende and augite exhibit normal and reverse zoning even in the same sample. The new field, textural, mineral compositional, and geochemical evidence leads to the conclusion that MME could have formed through injection of successive pulses of basic magma into upward mobile magma chambers containing cooler, partially crystalline quartz diorite magma. The quartz diorites show similarity to high-Al TTG (tonalites-trondhjemites-granodiorites), with their high Na2O, Sr, LREE, and low Mg#, Cr, HREE contents, and are suggested to be produced by extensive interaction between the crustal and mantle-derived melts through mixing at depth. In contrast, leucogranites have geochemical characteristics distinct from the quartz diorites and MME, and are probably not involved in MME genesis.Öğe Interaction of the lithospheric mantle and crustal melts for the generation of the Horoz pluton (Nigde, Turkey): whole-rock geochemical and Sr-Nd-Pb isotopic evidence(ESTONIAN ACADEMY PUBLISHERS, 2016) Kocak, Kerim; Zedef, VeyselThe Horoz pluton includes granitic and granodioritic rocks, with widespread mafic microgranular enclaves (MMEs). Petrochemically, the rocks of the pluton show calc-alkaline to shoshonitic and metaluminous to slightly peraluminous composition. The rocks also exhibit an enrichment in large ion lithophile elements, e.g. Rb, K, and depletions of high field strength elements such as Y, Lu, and Mg#, Ni, with a slightly concave-upward rare earth element pattern. Both granitic and granodioritic rocks exhibit geochemical characteristics of tonalite, trondhjemite and granodiorite assemblages, possibly developed by the partial melting of a thickened lower crust. The granitoids have high concentrations of Na2O (2.6-4.5 wt%), Sr (347-599 ppm), intermediate-high (La/Yb)(N) (8.2-18.1, mostly >11), Al2O3 (13.2-16.9 wt%, average 15.3 wt%), low MgO (0.2-1.4 wt%, average 0.84 wt%) and Co (0.7-10.3 ppm). The MMEs include higher Na2O (4.5-5.5 wt%), Sr (389-1149 ppm), Al2O3 (16.9-19.2 wt%, average 17.8 wt%), MgO (1.4-4.4 wt%, average 2.75 wt%) and Co (6.2-18.7 ppm) contents in comparison with that of their hosts. There is a lack of negative Eu anomalies, except a few samples. Both host rocks and MMEs have a low initial Sr-87/Sr-86 ratio (respectively 0.7046-0.7051 and 0.7047-0.7058), low epsilon(Nd) value (-1.8 to -0.2 and -0.6 to 0.7 at 50 Ma) and highly radiogenic Pb-208/Pb-204 ratios (39.43-39.47 and 39.39-39.54). Whole-rock chemistry and isotopic data suggest that parent magmas of both MMEs and their hosts have derived from melts of the mixing between the lithospheric mantle and crustal end members, than fractional crystallization processes in crustal levels.Öğe Magma mixing/mingling in the Eocene Horoz (Nigde) granitoids, Central southern Turkey: evidence from mafic microgranular enclaves(SPRINGER WIEN, 2011) Kocak, Kerim; Zedef, Veysel; Kansun, GurselMafic microgranular enclaves (MMEs) are widespread in the Horoz pluton with granodiorite and granite units. Rounded to elliptical MMEs have variable size (from a few centimetres up to metres) and are generally fine-grained with typical magmatic textures. The plagioclase compositions of the MMEs range from An(18)-An(64) in the cores to An(17)-An(29) in the rims, while that of the host rocks varies from An(17) to An(55) in the cores to An(07) to An(33) in the rims. The biotite is mostly eastonitic, and the calcic-amphibole is magnesio-hornblende and edenite. Oxygen fugacity estimates from both groups' biotites suggest that the Horoz magma possibly crystallised at fO(2) conditions above the nickel-nickel oxide (NNO) buffer. The significance of magma mixing in their genesis is highlighted by various petrographic and mineralogical characteristics such as resorption surfaces in plagioclases and amphibole; quartz ocelli rimmed by biotite and amphibole; sieve and boxy cellular textures, and sharp zoning discontinuities in plagioclase. The importance of magma mixing is also evident in the amphiboles of the host rocks, which are slightly richer in Si, Fe3+ and Mg in comparison with the amphiboles of MMEs. However, the compositional similarity of the plagioclase and biotite phenocrysts from MMEs and their host rocks suggests that the MMEs were predominantly equilibrated with their hosts. Evidence from petrography and mineral chemistry suggests that the adakitic Horoz MMEs could be developed from a mantle-derived, water-rich magma (> 3 mass%) affected by a mixing of felsic melt at P > 2.3 kbar, T > 730A degrees C.Öğe Mineralogy, geochemistry, and Sr-Nd isotopes of the Cretaceous leucogranite from Karamadaz (Kayseri), central Turkey: implications for their sources and geological setting(CANADIAN SCIENCE PUBLISHING, 2008) Kocak, KerimThe leucogranite is the major constituent of the bimodal Late Cretaceous Karamadaz granitoid, developed in relation with evolution of the Inner Tauride Ocean along the northern margin of the Taurides in central Turkey. New analyses of minerals major and trace elements (including rare-earth elements (REE)), and of Sr and Nd isotopes are performed to determine the origin and geochemical characteristics of the leucogranites. Medium-coarse-grained leucogranite contains normally zoned plagioclase (An(12-20)), mildly alkaline biotite, and xenocrystic magneziohornblende, actinolite, and ferrohornblende. It is characterized by concave-up REE patterns with respect to middle-heavy REE. Field relations, mineral chemistry, geochemical data, and isotopic data suggest that the leucogranite could have originated from an amphibole-bearing igneous source in lower to middle crust by low-rate partial melting (< 40%) under low pressure and low H2O activity conditions, possibly coupled by mixing-mingling with mafic magma and high-level feldspar and minor biotite fractionation. In contrast, the quartz diorite and mafic microgranular enclave (MME) are probably developed from an enriched mantle, with possible mingling-mixing. MME, quartz diorite, and leucogranite may represent a magmatic suite, which formed in an extensional tectonic regime by bimodal magmatic activity probably because of lithospheric delamination or slab break off or after the Alpine thicken within the Gondwanan Tauride-Anatolide platform. Initial Sr data exhibit an age of 65 +/- 13 Ma for the leucogranite, but it does not indicate a true intrusion age of the magma due to isotopic modification of the magma.Öğe Petrogenesis of the uckapl Granitoid and its Mafic Enclaves in Elmal Area (Nide, Central Anatolia, Turkey)(WILEY, 2013) Kurt, Huseyin; Kocak, Kerim; Asan, Kursad; Karakas, MustafaThe Late Cretaceous uckapl Granitoid including mafic microgranular enclaves intruded into metapelitic and metabasic rocks, and overlain unconformably by Neogene ignimbrites in the Nigde 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 uckapl 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 uckapl 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 uckapl Granitoid has relatively high (SrSr(i))-Sr-87-Sr-86 ratios (0.711189-0.716061) and low epsilon Nd-(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 uckapl granitoid is H-(hybrid) type, post-collision granitoid developed by mixing/mingling processes between crustal melts and mantle-derived mafic magmas.Öğe Stratigraphic Characteristics of the Derinkuyu Area, Nevsehir, Turkey(SPRINGER INT PUBLISHING AG, 2014) Sogut, Ali Riza; Kocak, Kerim; Guzel, AhmetThe study area is located in the Derinkuyu area, central Anatolia. The oldest formation in the area is Cretaceous Karatepe hornblende gabbro, which is overlain by upper Miocene Melendizdagi tuffs, Melendizdagi andesites, Gostuk tuff and ignimbrite, and the Karakaya Formation. These units are followed by lower Pliocene Selime tuff, Kizilkaya ignimbrite, and the Agilli Formation, above which lie various Pleistocene ashes, namely, the Hasandagi ash, the Kumtepe ash, and the Golludag ash flow tuffs. Above these are the Pleistocene Kizildag basalts and Holocene basaltic cinder cones. Talus is the youngest unit in the area. The young volcanics and volcaniclastics in the area may have originated from the volcanism of Mts Erciyes, Melendiz, and Hasan.Öğe Stratigraphic Features of the Yesilova Ophiolite, Burdur, South-Western Turkey(SPRINGER INT PUBLISHING AG, 2014) Doyen, Adnan; Comlekciler, Fuat; Kocak, KerimThe Yesilova ophiolite is located in the Alpine zone as a major part of the Lycian nappes of western Taurus. It was formed at the southern branch of Neo-Tethys, and was abducted over the southern edge of the Menderes Massif during the Cenonian during Laramian orogenesis. The ophiolite in the study area starts with tectonite, consisting mainly of harzburgites (37.02 % MgO, 38.77 % SiO2, and 0.42 % Cr2O3) and smaller amounts of dunite and chromite pods. The sequence continues with cumulates, including (from bottom to top) dunite, wehrlite, clinopyroxenite, layered and nonlayered gabbro (45.53 % SiO2, 11.92 % Al2O3, and 13.11 % MgO), and plagiogranite (77.41 % SiO2, 0.25 % K2O). The tectonite and cumulates have been cut by isolated gabbro and diabase dikes. The altered volcanites are found at the top of ophiolitic sequence, and were abducted by the Upper Cretaceous Kizilcadag Melange, with limestone, chert-radiolarite blocks, and ophiolitic rock fragments. The upper Eocene Varsakyayla Formation rests over the melange; it contains abundant nummulites and is composed of conglomerate sandstone, limestone, and conglomerate towards the top. The stratigraphic sequence continues with the Pliocene-Quaternary Niyazlar Formation, consisting of terrigenous conglomerate intercalated with sandstone, and ends with rock talus and alluvium.
