Mineralogical and Chemical Characteristics of Clay Areas,Gümüşhane Region (NE Turkey), and Their Detection Using the Crósta Technique with Landsat 7 and 8 Images

Natural Resources Research - The clay areas in Gümü?hane (NE Turkey) were examined in mineralogical and geochemical terms, and by remote sensing methods. X-ray diffraction, scanning...     

Geochemistry of dacitic volcanics in the Eastern Pontides (NE Turkey)

Dacitic rocks that crop out around the Zigana Mountain (Gümü?hane) in the eastern Pontide (NE Turkey), are mainly composed of quartz, plagioclase, sanidine, amphibole, muscovite, and biotite as the main minerals. Zircon and rutile are the accessory minerals. Pyrite, chalcopyrite, and covellite are the opaque components. On the basis of trace-element data, dacites have been classified as Dacite-I and Dacite-II. Dacite-I is tholeitic-transitional, whereas Dacite-II is transitional-calc-alkaline. The geochemical variation can be explained by the fractionation of the common mineral phases, such as plagioclase, hornblende, magnetite, and apatite. Dacites also show island-arc properties, with negative Nb, Sr, P, and Ti anomalies. The trace-element distrubitions of the dacitic rocks reflect the typical characteristics of rocks from the subduction-related tectonic setting, with enrichment of large-ion lithofile elements and light rare-earth element, but depletion in high-field-strength elements. The dacitic rocks are developed through plagioclase ± hornblende-controlled fractionation from the same parental magma that settled in two successive stages and are derived from an enriched source, probably by the mixing of slab-derived and lithospheric melts.     

Petrogenesis of the late Cretaceous Turnagoel intrusion in the eastern Pontides： Implications for magma genesis in the arc setting

A series of Cretaceous plutons is present in the eastern Pontides of northeastern Turkey.The Turnagl intrusion is the least studied and,thus,the least understood plutons in the orogen.This intrusion consists of hornblende-biotite granodiorites emplaced at 78 Ma based on LA-ICP-MS U-Pb zircon dating.It is of sub- alkaline affinity,belongs to the medium- to high-K calc-alkaline series,and displays features typical of Itype granites.The rocks of the intrusion are enriched in large-ion lithophile elements and light rare earthelements with negative Eu anomalies（Eu/Eu^*= 0.69-0.82）,but are deficient in high-field-strength elements.They have a small range of (⁸⁷Sr/⁸⁶Sr)_i（0.7060-0.7063）,ε_Ndi（-2.6 to -3.1）,and δ¹⁸O（+8.1 to +9.1） values.Their Pb isotopic ratios are ²⁰⁶Pb/²⁰⁴Pb = 18.63-18.65,²⁰⁷Pb/²⁰⁴Pb = 15.62-15.63,and ²⁰⁸Pb/²⁰⁴Pb = 38.53-38.55.The fractionation of plagioclase,hornblende,and Fe-Ti oxides had key functions in the evolution of the Tumagl intrusion.The crystallization temperatures of the melts ranged from 758 to 885℃ as determined by zircon and apatite saturation thermometry.All these characteristics,combined with the low values of K₂O/Na₂O and（Na₂O + K₂O）/（FeO^t+MgO + TiO₂）,as well as the high values of （CaO + FeO^t + MgO + TiO₂）.suggest an origin by dehydration melting from a metabasaltic lowercrustal source.     

Trace and rare earth elements as indicators of provenance and depositional environments of Lias cherts in Gumushane,NE Turkey

Trace elements and rare earth elements (REEs) of Lias-aged cherts in the Gumushane area were studied in order to understand their origin and depositional environment. Twenty three chert samples from five stratigraphic sections were analysed by inductively coupled plasma-mass spectrometry, X-ray diffraction, and mineralogical investigation. Lias cherts in the study area are microcrystalline, cryptocrystalline quartz, and megaquartz depending on mineralogical content. Trace elements of the cherts were compared with PAAS, Co, Y, and Th had stronger depletions in the five sections, whereas V, Ni, Zr, Nb, and Hf had smaller depletions. The distribution of Zr, Hf, and Ta yields Zr/Hf, Zr/Ta and Hf/Ta ratios (25/645, 37/665, and 0.18/3, respectively) that differ from those of chondrites and average upper continental crust, suggesting that these elements are likely non-detrital but are sourced from seawater. Th/U ratios range from 0.04 to 0.45 and are lower than those of the upper continental crust (average: 3.9). Lias-aged cherts have low total REE abundances and stronger depletions in five sections of the PAAS and chondrite-normalised plots. The cherts are characterised by a positive Eu anomaly (average: 4.9) and LREE-enrichment (La_N/Yb_N = average: 3.5). In addition, about one-half of the cherts exhibit positive Ce anomaly (range: 0.25–2.58), chondritic Y/Ho values (range: 3.3–60), and low (La/Ce)_N values (average: 1.8). REE and trace element abundance in Lias cherts indicate that these elements were likely derived from hydrothermal solutions, terrigenous sources, and seawater. The REE patterns of the cherts show that they were probably deposited close to a continental margin.     

Investigation of the quality and physical-geochemical characteristics of the drinking water in Gümüşhane (Turkey) city central

The physical (turbidity, color, smell, taste, pH, and conductivity) and geochemical properties (Ca, Mg, Na, Fe, Mn, Al, K, Cl^?, HCO₃ ^?, SO₄ ^2?, Fe, Cu, Co, Ni, Zn, Cd, Pb, and Cr) of the drinking water in Gümü?hane city center were determined. This city center constitutes the study area. The pH levels of the water samples ranged from 6.3 to 8.2, and their conductivities ranged between 240 and 900 μS. These findings were concordant with the drinking water standards of the Turkey Standard Institute and the World Health Organization. The hardness of the water samples in the study area was between 18.1 and 115.1 °Fr. These samples were classified as extremely hard, hard, and quite hard. In addition, an assessment using the criteria for Inland Surface Water Classification indicated that considering certain parameters (pH levels, amount of Na, SO₄ ^2?, Fe, Mn, Al, Co, Ni, Cu, and Cr), the samples belonged to class I (high quality) water. When Cl^? amount and conductivity were considered, the samples belonged to the first and second classes (less polluted) of water. The water in the study area was generally classified as carbonated and sulfated (Ca + Mg > Na + K) water classes. This water contained more weak acids than strong acids (HCO₃ ^? + CO₃ ^2? > Cl^? + SO₄ ^2?). The pH levels (6.3–8.2) of the water in the study area were unrelated to the varying concentrations of metals in the water. Elements such as Fe, Ni, Cd, Pb, Zn, and Cu increase in the water through the water–rock interaction in the area in which water rises or through the mixture of water with either mine or industrial wastes. In addition, several water samples belonged to an acceptable water class for drinking and usage.