Sulfur isotopes in Finnish nickel-copper occurrences

Abstract

The sulfur isotope composition of the Hitura, Kotalahti and Kylmä-koski Ni-Cu ores was analyzed. The results have been compared with earlier sulfur isotope analyses of the Vammala, Laukunkangas and Oravainen Ni-Cu occurrences. Altogether 183 analyses were performed. The magmatic origin of sulfides is supported by the isotope compositions that deviate only slightly from the meteoritic value. It is suggested that the initial sulfur isotope composition was homogeneous, ö® 4 S values being ca. + 2.5 at Hitura, + 2.0 at Kotalahti, close to zero at Kylmäkoski and at Laukunkangas, -1 at Vammala and + 2.8 at Oravainen. The metamorphic redistribution of sulfides and the mixing of magmatic Ni-Cu sulfides with wall-rock iron sulfides cause local variations in <5 84 S values.

Syn-mineralization hydrous fluid activity in giant Jinchuan magmatic Ni-Cu sulfide deposit in North China Craton

“…Majority of the δ 34 S values of the sulfide of the Jinchuan deposit range from − 2 to +2 ‰ (Duan et al, 2016;Gao et al, 2022;Ripley et al, 2005), similar to that of the orogenic magmatic Ni-Cu sulfide deposits. Examples include Hongqiling (δ 34 S = − 2.2 to +0.9 ‰, Hao et al, 2014), Piaohechuan deposit (δ 34 S = − 0.5 to +1.0 ‰, Wei et al, 2019), Kalatongke (δ 34 S = − 1.86 to +1.74 ‰, Tang et al, 2020) in the Central Asian Orogenic Belt and many Ni-Cu deposits (δ 34 S = − 1 to +2.8 ‰, Papunen and Mäkelä, 1980) in the Kotalahti and Vammala belts in Finland. These values are close to the range characteristic of mantle-derived sulfur δ 34 S, which undermine the effect of external sulfur on the sulfide saturation.…”