Geochemical and mineralogical studies of submarine hydrothermal systems in Lau Backarc Basin

Abstract

Active submarine hydrothermal activities have been located in Valu Fa Ridge, in the Lau Backarc Basin. In these sites, abundanta sulfide-sulfate deposits were observed associated with active venting of hydrothermal fluids. Among sulfide deposits, Cu-rich sulfides were associted with higher temperature venting (>300C), while Zn-rich sulfides were associted with moderate temperature (250-300C). Amond old deposits, significant amount of barite was notified. We will discuss relationship with fluid chemistry, which showed extremely low acid due to magmatic volatile involvement.