Source of the mineralizing fluids in ultramafic related magnesite in the Eskişehir area, northwest Turkey, along the İzmir–Ankara Suture: a stable isotope study

Authors : Asuman KAHYA, Mustafa KUŞCU

Pages : 1-15

Doi:10.3906/kim-1204-56

View : 16 | Download : 10

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The Eskişehir magnesite deposits insert ignore into journalissuearticles values(Süleymaniye, Margı, and Tutluca); are located in the western part of the İzmir-Ankara Suture Zone, northwestern Turkey. These vein and stockwork type magnesite deposits, which occur along major and minor fault systems, are hosted by Alpine-type ultramafic rocks. The purpose of this study was to understand the origin of the hydrothermal waters responsible and the source of carbon dioxide, and to compare these deposits with similar magnesite occurrences in Turkey and elsewhere. Petrographic and XRD analyses indicate that magnesite was the major carbonate mineral formed. Deposits are predominantly micritic and locally microsparitic, but some also contain secondary calcite and dolomite. The delta13C insert ignore into journalissuearticles values(V-PDB); values of the Süleymaniye magnesites insert ignore into journalissuearticles values(-2.7%o to -7.7%o);, the Margı magnesites insert ignore into journalissuearticles values(-7.6%o to -11.2%o);, and the Tutluca magnesites insert ignore into journalissuearticles values(-8.7%o to -10.4%o); indicate that sources of carbon may include atmospheric carbon, dissolved inorganic carbon, freshwater carbonate, and mantle derived CO2. The delta18O insert ignore into journalissuearticles values(SMOW); compositions of the magnesite range from 27.4%o to 30.8%o and show that the oxygen was derived from marine limestone and metamorphic rocks. The Süleymaniye magnesites have heavier carbon isotopic values than the others because of the greater contribution of mantle sourced CO2, while oxygen isotopic values were similar to those of other altered ultramafic related magnesites in Europe insert ignore into journalissuearticles values(Former Yugoslavia, Greece);. The Margı and the Tutluca magnesite deposits have carbon and oxygen isotopic values similar to those of other ultramafic-related magnesite deposits. Based on isotopic data, we argue that the magnesite deposits in the Eskişehir area formed in a near surface environment at low pressure and temperature. The estimated temperature, using average delta18O values, suggests that magnesite was precipitated from water at 37 °C.
Keywords : Key words Magnesite, stockwork, vein, Eskişehir, isotope geochemistry