An experimental investigation of high-temperature interactions between seawater and rhyolite, andesite, basalt and peridotite

摘要: Natural seawater was allowed to react with rhyolite, andesite, basalt, and peridotite at 200°–500° C, 1,000 bars water/rock mass ratios of 5 50 in order investigate the effects rock type, ratio, temperature on solution chemistry alteration mineralogy. The results indicate that interactions various igneous rocks are similar production a hydrous Mg-silicate anhydrite as major products. Fluids involved lose Mg phases while leaching Fe, Mn, Si from rocks. pH solutions is primarily controlled by Mg-OH-silicate formation therefore varies concentration system. Other reactions which involve (such Mg-Ca exchange) or produce free H+, cause differences fluid between different seawater/ systems. High ratio systems (50/1) generally more acidic efficient than low (5/1), due relatively available for Mgsilicate production. experiments show large-scale seawater/rock interaction could exert considerable control seawater, well producing large bodies altered associated ore-deposits.