Genesis of hydrothermal stockwork-type magnesite deposits associated with ophiolite complexes in the Kutahya-Eskisehir region, Turkey

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

“…Here, we describe the source of the carbon and the precipitation temperature of the magnesite deposits in the Eskişehir area. Similar studies by Ece et al (2005) nearby, by Zedef et al (2000) in southwest Turkey, and by Kadir et al (2013) in northeast Turkey reveal controversies regarding the origin of the magnesite, the source of the carbon, and the precipitation temperature. In this study, we use stable isotope analysis to constrain the source of the mineralizing fluids and to assess the conditions of formation of the magnesite deposits.…”

“…For these models, supergene, hypogene, and combined processes have been proposed (Frank and Fielding, 2003). Fallick et al (1991), Zedef et al (2000), Ece et al (2005), Mirnejad et al (2008), and Kadir et al (2013) explained the formation of magnesite deposits related to ultramafic rocks in the Alpine orogenic belt as reflecting a combination of supergene and hypogene processes. Gartzos (1990) proposed a mixing model of ascending CO 2 -rich fluids with descending meteoric water, precipitation of magnesite occurs below 60 °C, based on isotopic data.…”

“…Atmospheric CO 2 (e.g., O'Neil and Barnes, 1971;Zedef et al, 2000), 2. Decarboxylation of organic-rich sediments (e.g., Fallick et al, 1991;Brydie et al, 1993;Zedef et al, 2000;Ece et al, 2005), 3. Thermal decarbonation of limestone (e.g., Fallick et al, 1991;Zedef et al, 2000;Ece et al, 2005), 4.…”

“…These values show that the source of oxygen in all magnesite deposits (Süleymaniye, Margı, and Tutluca) came from marine limestone and metamorphic rocks (Criss, 1999; Figure 7). Zedef et al (2000) and Ece et al (2005) Gartzos, 1990;Zedef et al, 2000;Ece et al, 2005). The δ 13 C values of the Süleymaniye, Margı, and Tutluca magnesite deposits are given in Table 1 C values obtained indicate that the sources of CO 2 in magnesites in the study area were atmospheric CO 2 , dissolved inorganic carbon (from underground), freshwater carbonate, and mantle derived CO 2 (Clark and Fritz, 1997; Figure 8).…”

“…These higher δ 13 C isotopic values are related to the more effective mantle derived CO 2 . Fallick et al (1991), Zedef et al (2000), Brydies et al (1993), and Ece et al (2005) all suggest that δ 13 C V-PDB values between -10‰ and -15‰ indicate a contribution of carbonate from decarboxylation of organic-rich sediments, which may be overthrust by the ultramafic rocks. Curtis (1978) and Emergy and Robinson (1993) indicate that the decarboxylation of organic-rich sediments begins at temperatures of around 70 to 75 °C.…”