The origin of magnesite deposits from the Polish Foresudetic Block ophiolites: preliminary δ13C and δ18O investigations |
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| Authors: | M Orion Jedrysek Stanislaw Halas |
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| Institution: | Mass Spectrometry Laboratory, Institute of Physics, Maria Curie-Sklodowska University, 20–031 Lublin;Institute of Geological Sciences, Wroclaw University, 50–205 Wroclaw, Poland |
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| Abstract: | Twenty-three magnesite samples from vein deposits, found in ultramafic rocks related to ophiolites in the north-east Bohemian Massif, have been examined for carbon and oxygen isotope ratios. In these rocks two stages of antigorite serpentinization took place prior to magnesite precipitation. δ18OSMOW in magnesites ranges from 24.5 to 27.9%o (corrected for acid fractionation factor) which leads us to conclude a meteoric origin of the ore-forming solution. This inference is further supported by δ13C values (?18.7 to ?4.4%o) which point to a biogenic origin of carbon in the magnesites. |
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