Interaction of the lithospheric mantle and crustal melts for the generation of the Horoz pluton (Niğde, Turkey): whole-rock geochemical and Sr–Nd–Pb isotopic evidence

The 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 87Sr/86Sr ratio (respectively 0.7046–0.7051 and 0.7047–0.7058), low eNd value (–1.8 to –0.2 and –0.6 to 0.7 at 50 Ma) and highly radiogenic 208Pb/204Pb 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

Genesis of vein stockwork and sedimentary magnesite and hydromagnesite deposits in the ultramafic terranes of southwestern Turkey: A stable isotope study

Vein stockworks and lacustrine developments of cryptocrystalline magnesium carbonates of Neogene and Quaternary age occur within the partially serpentinized, discontinuous ultramafic belts of southwestern Turkey. They are comparable to the Neogene cryptocrystalline magnesite bodies elsewhere in the Alpine orogen to the northwest and southeast. Our previous work (Fallick et al., 1991) suggested that cool (less than or equal to 100 degrees C) modified meteoric water was the mineralizer, that ultramafic rock was the source of the magnesium, but that there were three separate sources of the (bi)carbonate. These sources were distinguishable by their stable isotope composition as follows: (1) low-temperature carbonate with delta(18)O((SMOW)) values of similar to 36 per mil and delta(13)C((PDB)) values of similar to 4 per mil, derived from atmospheric CO2; (2) moderate-temperature carbonate with delta(18)O((SMOW)) values of +28 per mil and delta(13)C((PDB)) values of -15 per mil, derived by decarboxylation of organic-rich sediments; and (3) higher temperature carbonate with delta(18)O((SMOW)) values of similar to 19 per mil and delta(13)C((PDB)) values of similar to 3 per mil, assumed to have been generated by thermal contact metamorphism of Paleozoic marine limestone at depth. In general these magnesite deposits were found to fall into two groups, comprising carbonate generated on two mixing lines. The first group spanned the putative mixing line from the "atmospheric" source (1) to "organically derived" source of CO2 (2). The second group extended between atmospheric source (1) and the "thermal" source (3), although there were concentrations either around the atmospheric end, or precisely at the contact metamorphic end of the line. In the present study we found that large stockwork deposits at Helvacibaba and Koyakci Tepe have delta(13)C((PDB)) and delta(18)O((SMOW)) values averaging similar to-12 and similar to+27 per mil, respectively, indicating a derivation mainly by oxidation of organic-rich metasediments perhaps underthrust at depth (end-member 2), with some involvement of atmospheric carbon dioxide as bicarbonate in the circulating, hot, and modified meteoric water (end- member 1). Calcite veinlets in a meta-argillite of the Cambro- Ordovician Seydisehir Formation, most likely to have been underthrust beneath the stockworks, yielded delta(13)C((PDB)) values of -20 per mil, consistent with, though not proving, oxidized organic carbon being one of the sources of carbonate. The delta(18)O((SMOW)) values of these same veinlet carbonates are also rather low (22 parts per thousand), indicating precipitation from heated ground water, though their age is unknown. The major stratiform magnesite deposit at Hirsizdere in the center of the Menderes graben has delta(13)C((PDB)) and delta(18)O((SMOW)), values averaging similar to 3 and similar to 25 per mil, respectively and thus appears to be an example of the hydrothermal-sedimentary (i.e., exhalative) type (Ilich, 1968). In contrast, the hydromagnesite stromatolites presently growing in Salda Golu (Lake Salda) are apparently developing at cool ground-water seepages. The gross morphology of the Salda Golu stromatolites and the hydromagnesite sediments derived therefrom is reminiscent of that revealed in the Bela Stena magnesite pit in Serbia. These lacustrine deposits have mean delta(13)C((PDB)) values of similar to 4 and similar to 2 per mil and mean delta(18)O((SMOW)) values of similar to 36 and similar to 33 per mil, respectively, i.e., they both plot broadly over the atmospheric CO2-meteoric water field (end- member 1), consistent with microbially mediated precipitation at cool ground-water seepages in enclosed evaporating lakes

Effects of different drying temperatures on the physical and mechanical properties of some marbles (Muğla, Turkey) during salt crystallization tests

This study aims to understand the effects of drying temperatures during sodium sulphate salt crystallization tests on the physico-mechanical properties of some Mug. la marbles. Four commercially available and extensively used Turkish marbles, namely Mug. la white, Milas white, Derebag white and Milas Pearl, having different textural properties were subjected to sodium sulphate salt crystallization tests with 30, 60 and 100 degrees C drying temperatures. The change in the physico-mechanical properties of the marbles including weight, dry and saturated unit weights, water absorption, effective porosity, dry and saturated sonic velocities and dry uniaxial compressive strength has been determined for various stages of the salt crystallization tests. The results were evaluated in terms of drying temperatures and the textural properties of the marbles. Based on the test results, the salt crystallization with the drying temperature of 100 degrees C causes significant damage to all marbles. However, the drying temperature of the test at 60 degrees C gives rise to moderate damage, whereas the drying of the marbles at 30 degrees C gives the least damage. Therefore, the drying temperature of the salt crystallization tests should be less than 60 degrees C and preferably around 30 degrees C in order to avoid additional thermal effects on marbles. Furthermore, the fine-gained Milas pearl marble with irregular grain boundary is found to be the most resistant one against the salt crystallization

Assessment of Shoreline Changes using Historical Satellite Images and Geospatial Analysis along the Lake Salda in Turkey

WOS: 000527535700001This study was performed along the shorelines of Lake Salda in Turkey during the elapsed period from 1975 to 2019 in order to detect shoreline changes. Within this framework, geographic information system, digital shoreline analysis system, Modified Normalized Difference Water Index, and multi-temporal satellite images were utilized. The measurement of shoreline displacement was mainly divided into six analysis regions. In digital shoreline analysis system, several statistical parameters such as end point rate, linear regression rate, shoreline change envelope, and net shoreline movement were computed to measure the rates of shoreline displacement in terms of erosion and accretion. The maximum shoreline change between 1975 and 2019 was determined as 556.45 m by shoreline change envelope parameter. The maximum shoreline change was 16.35 m/year by end point rate parameter and 12.91 m/year by linear regression rate parameter. While erosion has been observed in 3rd, 4th and 6th segments, accretion has been observed in other segments. When all the transects were taken into consideration, an accretion observed. The results indicate that there is a decrease in area of the lake. Experiment results show that integrated use of multi-temporal satellite images and statistical parameters are very effective and useful for shoreline change analysis. It is thought that the structures such as irrigation pond and dam that are built on the streams that recharge the lake and average rainfall and average temperature conditions are the main reasons of the fluctuations and changes in the shorelines