Search

Extensive Late Miocene to Pliocene Erenlerdagi volcanism produced lava domes, nuee ardentes and ignimbrite deposits in west and southwest of the Konya. The domes may contain various enclaves, which range in size from a few cm to a few meters, and in shape cornered to spherical. The volcanic rocks are made up of plagioclase (15-45%), brown amphibole (3-15%), brown biotite (5-10 %), quartz (0-5%), sanidine (0-5%), clinopyroxene (0-5 %), epidote (0-8%), opaque iron ore (3-20%), and accessory acicular apatite and zircon in a holocrystalline porphyric texture. Geochemical data shows that all samples are high-K calc-alkaline, mostly metaluminous, and rhyodacite to andesite in composition. They are characterized by an enrichment in Large Ion lithophile Elements (e.g. Cs, K), and a depletion in High Field Strength Elements (e.g. Ti, Y). In Harker variation diagrams, SiO2 increases with increasing K2O, Na2O, Rb, Th, U, Nb, Zr contents; and decreasing TiO2, FeOt, MgO, CaO contents, suggesting fractional crystallisation of hornblende (± pyroxene, olivine) and titanite. The REE pattern of the samples shows an enrichment in Light Rare Earth Elements, and a depletion in Heavy Rare Earth Elements, resultant with high ((La/Lu)N= 8.2-18.0) ratios. Existence of slight Eu anomaly (Eu/Eu*: 0.66-0.80 ) may suggest plagioclase fractionation in the samples. Based on field, mineralogical and geochemical data, it has been suggested that the Erenlerdagi volcanics could have formed by chemical mixing of felsic and mafic magmas possibly coupled with fractional crystallisation of hornblende (± pyroxene, olivine), plagioclase and titanite, in relation with the subduction of the African plate underneath the Anatolian plate during Miocene.

Turkey hosts essential bauxite deposits, typically of the karstic-type. The most economically important bauxite deposits of Turkey form in the Seydisehir-Akseki region of the central Taurides Mountains. The Mortas and Dogankuzu deposits are the most important deposits in that region. The bauxite beds contain boehmite, hematite, rutile, smectite, quartz, diaspore, calcite, pyrite, marcasite and goethite. Brown to red-colored bauxite minerals are massive, oolitic – pisolitic textured. The Seydisehir schists could be possible parent rocks of bauxites, and have unearthed acidic source (mostly granite) with hornblende and plagioclase minerals. The schists were compositionally mature with minimal alkali feldspar sediments. The Mortas deposit is 400 m long and up to 40 m thick; it averages 10 m thick. It has about 5 million tons of ore reserves, with ~50 percent Al2O3. The Dogankuzu bauxite deposit is situated 2 km southwest of the Mortas deposit, with 14.9 million metric tons of ore at 61 percent Al2O3. The Dogankuzu ore was deposited on a fault-controlled karst surface of Cenomanian limestone succession, which was overlain by 5- to 10-cm-thick Santonian limestones. The bauxite has been mined by the Seydisehir aluminum factory, which was founded in 1973, and privatized in 2005. The plant is capable to produce 65.000 ton liquid aluminum per year, around 15% of Turkey’s Aluminum demand.

URL:http://sujest.selcuk.edu.tr/sumbtd/article/view/457 DOI: 10.15317/Scitech.2017.98, The natural rocks used today as well as in the history for a variety of purposes were a subject of different alteration, weathering and deterioration conditions. These conditions are strictly controlled by environment and nature of rock varieties (marble and stone). This study is a first approach to understand the relation between some geological features and behavior against salt (Na2SO4) decay of Moroccan marbles and stones. For this purpose, widely used four dolomitic limestones, two crystalline limestones, one limestone and one basalt sample (total 8) were chosen from Morocco. Extra attention paid to choose locations being a representative of all Moroccan country. The carbonate samples (limestone and dolomite) consist of mainly dolomite and calcite with micritic and sparitic cement. The sole, non-carbonaceous sample is basalt of Khenifra containing mainly plagioclase and pyroxene. In general, both bulk-dry and powder density values of the studied rock samples are homogeneous. The limestone of Bir Jdid has the highest (10.81 %) effective porosity and dry weight loss value (4.61 %). The loss on ignition value of the Khenifra basalt has the lowest value with 1.26 %. The loss on ignition values are also relatively uniform. The obtained data indicate that outdoor uses (especially in coastal areas) of limestones of Bir Jdid and dolomitic limestones of Taza are more risky than the others., Hem geçmiş dönemlerde hem de günümüzde çok çeşitli amaçlar için kullanılan doğal taşlar farklı ayrışma, dağılma ve bozunmaya uğramaktadırlar. Bu şartlar çevre ve kayacın türüne (mermer ve taş) sıkı sıkıya bağlıdır. Bu çalışma Fas mermerleri ve taşlarını tuza (Na2SO4) karşı dayanımlarını ve bazı jeolojik özelliklerini anlamak için yapılan ilk çalışmadır. Bunun için Fas’tan getirilen çok kullanılan 4 dolomit, 2 kristalize kireçtaşı, 1 kireçtaşı ve bir bazalt (toplam 8 adet) örneği seçilmiştir. Örnekler mümkün mertebe Fas’ın değişik yerlerinden seçilmiştir. Karbonat kayaçları (kireçtaşı ve dolomit) temel olarak dolomit ve kalsit minerallerinden müteşekkil olup çimento mikrit ve sparittir. Karbonatsız tek kayaç olan Khenifra bazaltı esasen plajiyoklas ve piroksen içerir. Genel olarak örneklerin kuru ve öğütülmüş ağırlıkları birbirlerine benzer. Bir Jdid kireçtaşları en yüksek etkili porozite (% 10.81) ve kuru ağırlık kaybına (%4.61) sahiptir. En düşük ateş zayiatı Khenifra bazaltlarındadır (%1.26). Ateş zayiatları genel olarak homojendir. Eldeki veriler Bir Jdid kireçtaşları ve Taza dolomitik kireçtaşlarının dışarda (özellikle sahil bölgelerinde) kullanımlarının diğerlerine göre daha riskli olduğuna işaret etmektedir.

The Late Cretaceous Uckapili 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 Uckapili 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 Uckapili 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 Uckapili Granitoid has relatively high 87 Sr/ 86 Sr(i) ratios (0.711189-0.716061) and low eNd(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 Uckapili granitoid is H-(hybrid) type, post-collision granitoid developed by mixing/mingling processes between crustal melts and mantle-derived mafic magmas.

Mafic 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 An18–An64 in the cores to An17–An29 in the rims, while that of the host rocks varies from An17 to An55 in the cores to An07 to An33 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 fO2 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 >730°C.

The rocks form as amphibolite ± garnet ± epidote and orthogneisses in the Pan-African basement of the Bitlis Massif. The petrochemical data of the studied metamorphic rocks suggest different igneous protoliths ranging from calcalkaline basalt to andesite in composition. Petrochemically, the rocks can be classified as group 1 (low Zr and La) and group 2 (high Zr and La), all showing various enrichments in large ion lithophiles and light rare earth elements, and a depletion in high-field strength elements, suggestive of a destructive plate margin setting. The protoliths of the all samples might have formed mostly by the partial melting of an enriched source, possibly coupled with the fractional crystallization of plagioclase, apatite, and titaniferous magnetite ± olivine ± clinopyroxene ± amphibole in relation with subduction-related magmatism neighboring the Andean-type active margins of Gondwana. The group 2 samples could, however, be generated by a relatively lower degree of the partial melting of an inhomogeneous source with a preponderance of a high-level, fractional crystallization process in comparison to group 1. The protoliths of the samples were metamorphosed up to amphibolite facies conditions, which destroys original igneous texture and mineral assemblages. Geothermobarometric calculations show that the metamorphic rocks are finally equilibrated between 540 and 610°C and ∼5 kbars, following a clockwise P-T-t path.

The leucogranite is the major constituent of the bimodal Late Cretaceous Karamadazı 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 (An12–20), 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 (2O 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.

On 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 (An8-65), 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.

Many Neo-Tethyan ophiolitic bodies are well exposed as thrust-slices in Central Anatolia and are predominantly represented by massive hornblende gabbros, most of which are cut by Supra Subduction Zone (SSZ) plagiogranites. The allochthonous gabbros are distinct from their autochthonous counterparts, with their mineralogy including both igneous hornblende, relict diopside rimmed by replacement hornblende and their chemical composition corresponding mostly to gabbro rather than diorite. The results of major and trace element analyses of forty-two samples, and REE analyses of nine samples, indicate that the hornblende gabbros are SSZ-type and formed from a wet magma by high-degree partial melting of peridotite possibly coupled with contamination by predominantly neighbouring-slab derived fluids within an intra-oceanic back-arc basin. The mafic magmas then underwent high-level fractional crystallization involving titaniferous magnetite, diopside, tschermakite and possibly olivine. Emplacement was followed by extensive ocean–floor metamorphism, which has induced crystallization (or recrystallization) of chlorite, biotite, amphiboles and mobilisation of most of the major elements such as alkali and alkali earth elements, and some LREE.

The 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.

The geological history of a regionally metamorphosed sequence of Silurian on early Devonian sediments, now calcite marbles, quartzites, semipelitic, psammitic and migmatitic gneisses containing K-feldspar, sillimanite, and garnet with later andalusite and cordierite, is outlined with chemical analyses of the rocks and minerals, the latter suggesting peak metamorphic conditions about 600 to 700° C at 4kb. Deposition was in part at an active continental margin and in part probably at a passive margin and was followed by basic intrusions, now amphibolites. Later gabbroic rocks are shown for the first time by their geochemistry, especially REE, to be probably part of a major ophiolite sheet, tectonically emplaced and containing late magmatic or metamorphic hornblende. Later intrusive hornblende diorite, with appinitic (diorite dykes with voluminous euhedral hornblende) and calc-alkaline lamprophyric affinites, immediately preceded the intrusion of voluminous granitoids (granite, tonalite, quartz monzonite) of probably late Cretaceous to Palaeocene age, whose geochemistry indicates a continental volcanic arc setting. Neogene formations completed the rock sequence.

WOS: 000249189600003, 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.