Mineral Carbonation of Abyssal Serpentinites



This proposal seeks funds to conduct a systematic and comprehensive study of carbonatealtered serpentinites from mid-ocean ridges, continental rifted margins, forearc settings and an active shallow-water Lost City type serpentinization system. The composition and associations of secondary minerals in these rocks will be analyzed using a combination of classic and cutting edge analytical methods to unravel reaction pathways during CO2- sequestration. Phase petrology and geochemical reaction path modeling will be used to estimate gas fugacities, solute activities of intergranular fluids, temperature and overall water flux.

Furthermore, this proposal seeks funds to conduct a series of CO2-sequestration experiments to gain first insights into the, to date, poorly constrained evolution of fluid chemistry during mineral carbonation of serpentinite. Carbon-dioxide-enriched fluids will be reacted with serpentinized peridotite at constant temperature (T) and pressure (P). The role of the protolith composition and pCO2 will be explicitly addressed. Under well constrained P-T conditions the concentrations of relevant aqueous species can be used to deduce the dominant stable and metastable phase equilibria. The results will provide valuable new insights into the process of carbonate alteration in serpentinites, its consequences for CO2 exchange between the abyssal mantle and the oceans, and petrophysical property evolution during CO2- sequestration.