MULTIPLE SULFUR ISOTOPES IN ARCHEAN GRANITOIDS AND GREENSTONE, NORTH CHINA CRATON, LUXI AREA
Seminars
Semester 2
Mass-independent fractionation(MIF) of sulfur is a unique signal that was almost exclusively produced on the Earth’s surface before the great oxidization event. This distinctive feature makes it an excellent tracer of surface materials Archean lithosphere and mantle. In this study, we measured multiple sulfur isotopes in 2.7Ga-2.5Ga Archean granitoids and greenstone from Luxi area, North China Craton. Most samples have Δ33S around -0.05‰, and δ34S around 1‰, slightly deviate from the mass dependent fractionation line and the MORB value from modern mid ocean ridges. Granitoids with the lowest Δ33S values also display the highest sulfur concentrations, and their geochemical characteristics suggest interaction with mantle peridotite. Based on these observations, we interpret that granitoids with geochemical features of TTGs inherited their Δ33S values from metabasaltic rocks similar to the amphibolite samples analyzed in this study, while granitoids with features of sanukitoids may inherit their sulfur isotopic signals from a different source, possibly slab-derived fluid that metasomatized the upper mantle.
Additional information: Mr. SHANG Kun, kshang@connect.hku.hk