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    Ar-40/Ar-39 dating of ignimbrites and plinian air-fall layers from Cappadocia, Central Turkey: Implications to chronostratigraphic and Eastern Mediterranean palaeoenvironmental record
    (ELSEVIER GMBH, 2014) Lepetit, Petra; Viereck, Lothar; Piper, John D. A.; Sudo, Masafumi; Gurel, Ali; Copuroglu, Ibrahim; Gursoy, Halil
    Magmatism forming the Central Anatolian Volcanic Province of Cappadocia, central Turkey, records the last phase of Neotethyan subduction after similar to 11 Ma. Thirteen large calc-alkaline ignimbrite sheets form marker bands within the volcano-sedimentary succession (the Urgup Formation) and provide a robust chronostratigraphy for paleoecologic evaluation of the interleaved paleosols. This paper evaluates the chronologic record in the context of the radiometric, magnetostratigraphic and lithostratigraphic controls. Previous inconsistencies relating primarily to K/Ar evidence were reason for the initiation of an integrated study which includes Ar-40/Ar-39 dating, palaeomagnetic and stratigraphic evidence. The newly determined Ar-40/Ar-39-ages (Lepetit, 2010) are in agreement with Ar/Ar and U/Pb data meanwhile published by Pauquette and Le Pennec (2012) and Aydar et al. (2012). The Ar-40/Ar-39-ages restrict the end of the Urgup Formation to the late Miocene. The paleosol sequence enclosed by the ignimbrites is thus restricted to the late Miocene, the most intense formation of pedogene calcretes correlating with the Messinian Salinity Crisis. (C) 2014 Elsevier GmbH. All rights reserved.
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    GEOLOGICAL CHARACTERISTICS OF BOLKARDAĞI BAUXITE DEPOSITS IN AYRANCI, THE TAURUS MOUNTAIN, TURKEY
    (2023) Yalcın, Mustafa Gurhan; Copuroglu, Ibrahim
    The aim of this study is to determine the stratigraphic position of the bauxite deposits in the Ayrancı region, where the most important bauxite mineralization of the Bolkardağı region is located. In this context, the age of bauxite will be determined by determining the erosion surface associated with stratigraphic features during the formation of bauxite and the age of bauxite according to its side rocks. In the region, there are Permian-Cretaceous aged rocks belonging to the Bolkardağı Union, one of the main tectonic units forming the Central Taurus Mountains. Miocene units covering these rocks are surfaced in the study area. Karamanoglu ophiolite and older units are uncomfortably covered by Miocene aged Mazı and Divlek formations. Bauxite deposits are clearly seen in the Upper Permian aged Dedeköy formation. According to the field studies, the bauxites were formed in the Late Triassic - Early Jurassic interval, on the Upper Permian aged carbonate rocks and Lower Triassic aged shale - sandstone - limestone units and then deposited in caves and dolines within the carbonate rocks. The fact that bauxites are located above dolomites and below, within and above limestones is thought to be due to the different behavior of carbonate rocks.
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    MINERALOGICAL - PETROGRAPHIC AND GEOCHEMICAL INVESTIGATION OF CHROMITE DEPOSITS ASSOCIATED WITH KAYSERI (PINARBASI) OPHIOLITES
    (STEF92 TECHNOLOGY LTD, 2015) Sahinoglu, Alperen; Copuroglu, Ibrahim; Til, Baris
    The ophiolite of Pinarbasi covers an approximate area of 500 km(2) in the Kayseri-Pinarbasi area, South of the Central Anatolia Region and in the middle section of the Eastern Taurus Mountains. The rocks in this region consist of magmatic, metamorphic and sedimentary blocks enclosed within ophiolitic melanges and serpentinites of Upper Campanian - Maastrichtian age. The magmatic rocks within the melange are serpentinized harzburgite, tectonic dunite, gabroic cumulates, diabase dikes and volcanic rocks. Metamorphic rocks are represented with amphibolites. Sedimentary rocks mostly consist of volcanic sandstone, radiolaritine and shale. The ophiolites that surface in the vicinity of Kilicmehmet village that is the study area, consist of serpentinized harzburgite, diabase dikes, gabbro with olivine content, listvenites and serpentinites. Dunites and harzburgite in the area are observed to be serpentinized and exhibit sieve texture. Diabases on the other hand are holocrystalline granular textured, consist of plagioclase, pyroxene, low rates of amphibole and opaque minerals and exhibit subophitic texture. Gabbros have holocrystalline-hypidiomorph granular texture and are formed of 68% plagioclase (labrador), 22% clinopyroxene and 6% olivine. In this region ophiolite-based chromite mineralization are usually observed to be in banded form. Chromite bands are observed to be regular and in parallel zones. Ore-bearing zones stretch in N 10 degrees-30 degrees D direction and are sloped almost perpendicularly to SE. Ore-bearing zones exhibit thicknesses between 1 and 7 meters, direction lengths between 65 and 150 meters and slope lengths between 50 and 100 meters. Grates of chromites vary between 12.25% and 28.95%. Currently, chromite production activities continue in the region. In consequence of the interpretation and evaluation of the ratios calculated with trace element (ppm) and oxide % values obtained from chemical analyses, microprobe and SEM analyses, the determinations below were made. The average Cr2O3, Al2O3 and MgO contents of chromite samples are 22.21%, 6.03% and 22.56% respectively. The banded form of the examined chromites explains the relatively low rates of Cr2O3, Al2O3 and MgO. With the % Fe2O3, Al2O3 and Cr2O3 values obtained from the analysis of chromite minerals, it was determined that while 7 of the samples fall into the ferrochromite area, one sample falls into the chromemagnetite area of Stevens' triangular diagram that separates between chromemagnetite, ferrospinel, ferrochromite, chromospinel and aluminum magnetite. The interpretation of the 100Cr/(Cr + Al) and 100Mg/(Mg+Fe+2) values found in chemical analyses shows that none of the samples were in the stratiform and podiform chromite area. TiO2 values vary between 0.02% and 0.92%. According to these values, ophiolitic-stratiform chromite separation of chromite minerals was made on the TiO2-Cr2O3 diagram, and chromite minerals were found to be in the ophiolitic chromite area. In addition, since the Cr/Fe rates of the chromites in the study area are between 0.67 and 3.17, and their average Cr ratio is 2.03, it is considered that they also bear the quality of podiform chromite.
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    Mineralogical - Petrographic and geochemical investigation of chromite deposits associated with Kayseri (Pinarbasi) ophiolites
    (International Multidisciplinary Scientific Geoconference, 2015) Sahinoglu, Alperen; Copuroglu, Ibrahim; Til, Baris
    The ophiolite of Pinarbasi covers an approximate area of 500 km2 in the Kayseri- Pinarbasi area, South of the Central Anatolia Region and in the middle section of the Eastern Taurus Mountains. The rocks in this region consist of magmatic, metamorphic and sedimentary blocks enclosed within ophiolitic melanges and serpentinites of Upper Campanian - Maastrichtian age. The magmatic rocks within the melange are serpentinized harzburgite, tectonic dunite, gabroic cumulates, diabase dikes and volcanic rocks. Metamorphic rocks are represented with amphibolites. Sedimentary rocks mostly consist of volcanic sandstone, radiolaritine and shale. The ophiolites that surface in the vicinity of Kilicmehmet village that is the study area, consist of serpentinized harzburgite, diabase dikes, gabbro with olivine content, listvenites and serpentinites. Dunites and harzburgite in the area are observed to be serpentinized and exhibit sieve texture. Diabases on the other hand are holocrystalline granular textured, consist of plagioclase, pyroxene, low rates of amphibole and opaque minerals and exhibit subophitic texture. Gabbros have holocrystalline-hypidiomorph granular texture and are formed of 68% plagioclase (labrador), 22% clinopyroxene and 6% olivine. In this region ophiolite-based chromite mineralization are usually observed to be in banded form. Chromite bands are observed to be regular and in parallel zones. Orebearing zones stretch in N 10°- 30° D direction and are sloped almost perpendicularly to SE. Ore-bearing zones exhibit thicknesses between 1 and 7 meters, direction lengths between 65 and 150 meters and slope lengths between 50 and 100 meters. Grates of chromites vary between 12.25% and 28.95%. Currently, chromite production activities continue in the region. In consequence of the interpretation and evaluation of the ratios calculated with trace element (ppm) and oxide % values obtained from chemical analyses, microprobe and SEM analyses, the determinations below were made. The average Cr2O3, Al2O3 and MgO contents of chromite samples are 22.21%, 6.03% and 22.56% respectively. The banded form of the examined chromites explains the relatively low rates of Cr2O3, Al2O3 and MgO. With the % Fe2O3, Al2O3 and Cr2O3 values obtained from the analysis of chromite minerals, it was determined that while 7 of the samples fall into the ferrochromite area, one sample falls into the chromemagnetite area of Stevens' triangular diagram that separates between chromemagnetite, ferrospinel, ferrochromite, chromospinel and aluminum magnetite. The interpretation of the 100Cr/(Cr + Al) and 100Mg/(Mg+Fe+2) values found in chemical analyses shows that none of the samples were in the stratiform and podiform chromite area. TiO2 values vary between 0.02% and 0.92%. According to these values, ophiolitic-stratiform chromite separation of chromite minerals was made on the TiO2- Cr2O3 diagram, and chromite minerals were found to be in the ophiolitic chromite area. In addition, since the Cr/Fe rates of the chromites in the study area are between 0.67 and 3.17, and their average Cr ratio is 2.03, it is considered that they also bear the quality of podiform chromite. © SGEM2015.
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    Provenance discrimination among foreshore, backshore, and dune environments in the black sand beaches along the Samandag/Hatay coasts, SE Turkey (E Mediterranean)
    (SPRINGER HEIDELBERG, 2018) Ergin, Mustafa; Karakas, Zehra S.; Tekin, Erdogan; Eser, Basak; Sozeri, Koray; Copuroglu, Ibrahim; Simsek, Barbaros
    The occurrence of beach placers, the chromite-rich black sand, and the factors controlling their distribution along the Samandag coasts, SE Turkey, was investigated. One hundred fifty-two surficial (upper 2 to 5 cm) samples of beach sediments from foreshore, backshore, and dune subenvironments; 24 river sediments; 25 samples from ophiolitic source rocks; and ore samples from 4 chromitite mines were collected between the years 2012 and 2015. In addition to hydrogeographic and geomorphological field observations, grain size analysis and total heavy mineral separation and conventional petrographic microscopy studies were carried out. Bimodal, well to moderately well sorted, fine to medium sands were predominant, and on the basis of grain size distribution, at least six sectors could be distinguished by their alongshore fining or coarsening tendencies. Obviously, spatial variations in drainage pattern of fluvial input, wave and current motions, and beach morphology played a crucial role in changing sediment texture. The total heavy mineral (THM) concentrations ranged from 1 to 92 wt% (avg. 40 wt%) in beach sediments and from 3 to 50 wt% in fluvial sediments whereby the bed load of the major and perennial Asi River contained lower THM (9-25 wt%) than its ephemeral tributaries (14-50 wt%) which are in much closer proximity to the source areas. Overall, the THM concentrations in foreshore, backshore, and dune subenvironments tend to decrease in southward direction, except for THM enrichment close to the Asi River mouth. This would reflect rather higher inputs from northerly ephemeral rivers draining the ophiolitic rocks with additionally net longshore sediment transport towards south. The coastal physical processes favoring heavy mineral enrichment such as spatial and temporal variations in swashzone wave dynamics with uprush, backwash, and infiltration effects on the beaches were also observed in the field. The opaque heavy mineral fractions are mostly found in grain size less than 0.25 mm and composed of chromite, magnetite, and ilmenite species with intergrowth textures. Non-opaque heavy mineral fractions were dominated by various species of pyroxenes and amphiboles with lesser amounts of serpentinized olivine. Formation of chromite-rich black sand placers along the Samandag beaches (SE Turkey) and also in river/stream beds resulted from the weathering of mafic-ultramafic rock complexes ("Hatay or Kizildag Ophiolites") and chromite-rich ores of the Amanos Mountains to define the provenance of placers and no considerable input was detected from the Asi River downstream from the Bassaer ophiolites of Syria.