Experimental Simulations of Basalt-fluid Interaction at Supercritical Hydrothermal Condition (400°C - 500bar)

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• 作者：Mauro Passarella^a ; ^b ; ^{m.passarella@gns.cri.nz} ; Bruce W. Mountain^a ; Terry M. Seward^b
• 关键词：experimental geochemistry ; supercritical ; hydrothermal ; basalt-fluid interaction ; distilled water ; geothermal brine
• 刊名：Procedia Earth and Planetary Science
• 出版年：2017
• 出版时间：2017
• 年：2017
• 卷：17
• 期：Complete
• 页码：770-773
• 全文大小：489 K
• 卷排序：17

文摘

Two experimental simulations of basalt-fluid interaction under supercritical hydrothermal conditions have been carried out to examine the relationship between fluid and secondary mineral compositions with respect to pressure-temperature conditions and time. Fresh basalt was reacted with distilled water and geothermal brine at 400°C, 500bar using a flow-through high P-T hydrothermal apparatus. Results indicate that high silica concentrations, which reached quartz saturation, early in the experiments are due to the dissolution/devitrification of volcanic glass. Low pH is attributed to the release of sulfur from the glass. In the basalt-distilled water experiment, an assemblage of grossular - amphibole (possibly actinolite) - diopside was identified while in the brine experiment hornblende - biotite appeared as secondary phases. Fluid compositions are reasonably consistent with known mineral equilibria implying that reaction rates are extremely rapid at these conditions.