Trace Metals Distribution in Sulfide Minerals of the Ultramafic-Hosted Hydrothermal Systems: Example from the Kairei Vent Field, Central Indian Ridge

• DOI: 10.20944/preprints201809.0064.v1
• Publication Date: 2018-09-06T21:44:41Z
• Authors: Yejian Wang; Xiqiu Han; Sven Petersen; Matthias Frische; Zhongyan Qiu; Yiyang Cai; Peng Zhou
• Keywords: Ultramafic rock; Sulfide Minerals; Trace element

The ultramafic-hosted Kairei vent field, located at 25°19′S, 70°02′E towards the northern end of segment 1 Central Indian Ridge (CIR-S1) in a water depth ~2450 m. This study aims to investigate distribution trace elements among sulfides differing textures, and discuss possible factors controlling element those minerals by using LA-ICP-MS spot analyses as well line scans. Our results show that there are distinct systematic distributions throughout different minerals：(1) Pyrite is divided into three types Kairei, including early-stage euhedral pyrites (py-I), sub-euhedral (py-II), colloform (py-III). generally enriched Mo, Au, As, Tl, Mn, U. py-I have higher contents Se, Te, Bi, Ni, py-II Au relative py-III, but poor py-III Pb, U Au. Variations concentrations Bi pyrite likely governed strong temperature gradient. Ni lower than Co pyrites, indicates our samples precipitated high-temperature condition, whereas extreme enrichment from magmatic heat source combined serpentinization reactions underlie deposits. (2) Chalcopyrite characterized high Co, Te. abundant Se Te chalcopyrite cause solubilities incorporated lattice fluids. concentration Sb, As relatively low field. (3) Sphalerite both Zn-rich chimney Sn, Ga, Ge, Ag, Cd, depleted Ba, V, comparison with other minerals. Cd caused substitution Cd2+ Co2+ for Zn2+ sphalerite. A Pb accompanied Ag sphalerite indicating occurs microinclusions Pb-bearing such galena. correlate suggesting its presence correlation Ge suggests they might precipitate under medium- low-temperature moderately reduced conditions. (4) Bornite-digenite very most elements, except Bi. all sulfide was observed bornite-digenite can be explained Bi-selenide inclusions. Serpentinization hydrothermal systems play an important role on contents. Compared felsic-hosted seafloor massive (SMS) deposits, deposits attributed contribution volatile input. Significant has been found mafic-hosted SMSs indicate primary factor controls temperature-controlled mobility