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Ankara University (2017)

Isotope geochemistry (Sr-O-C-S) of Central Anatolian fluorite deposits

COŞANAY, Pelin

Titre : Isotope geochemistry (Sr-O-C-S) of Central Anatolian fluorite deposits

İç Anadolu florit yataklarının izotop (Sr-O-C-S) jeokimyası

Auteur : COŞANAY, Pelin

Université de soutenance : Ankara University

Grade : Master of Science (MS) 2017

Résumé
The Central Anatolian fluorite mineralizations are located on the northern part of Kırşehir Massif which is a part of Central Anatolian Crystalline Complex that is bordered by the İzmir-Ankara-Erzincan Suture Zone. The Kaman, Akçakent and Cankılı mineralizations are formed in association with syenite-nepheline syenite and monzonite/monzodiorite which are age of Upper Cretaceous. The Pöhrenk ore, is precipitated as space filling-breccia type within Eocene limestones and marl levels. The thickness of fluorite veins are quite variable and in these deposits fluorite occurs as a dark purple, green and yellow colored. Total REE+Y contents of fluorite mineralizations vary between 24-441 ppm. NTE concentrations of green fluorites are found to be greater than those of purple and yellow ones. Fluid inclusion studies indicated a range of homogenization temperature of 86-292°C and salinity range of 0 to 20 NaCl equivalent wt%. 87Sr/86Sr ratios imply that Kırşehir-Kaman fluorites are precipitated from a magmatic fluid or wall rocks significantly contributed Sr isotope input. The Pöhrenk fluorites are likely to be formed from Sr-poor fluids of marine origin. 143Nd/144Nd values of green fluorites are greater than purple ones. δ18O values of quartz samples are in the range of 14.3-15.4‰ whilst those for the Akçakent mineralization is 10.6-15.4‰ (VSMOW). These high δ18O values are conformable with granites from the upper crust. δ13C and δ18O values of calcites are -3.22 to -0.39 ‰ (VPDB) and 9.87 to 13.05‰ (VSMOW). Carbon in calcites is probably derived from marine sources. Low oxygen values indicate a systematic decrease as a result of interaction with meteoric water. δ34S values of barite and pyrite samples are between 2.9 and 20.3‰. Sulfur in pyrites has a magmatic origin while sulfur in barites is derived from marine sulfates

Mots clés : Florit, Orta Anadolu, jeokimya, radyojenik ve duraylı izotoplar, sıvı kapanım , Fluorite, Central Anatolia, geochemistry, radiogenic-stable isotope, fluid inclusion.

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Page publiée le 6 mai 2018