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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/16888
Role of fluid mixing in deep dissolution of carbonates
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The presence of cavities filled with new minerals in carbonate rocks is a common feature in oil reservoirs and lead-zinc deposits. Since groundwater equilibrates rapidly with carbonates, the presence of dissolution cavities in deep carbonate host rocks is a paradox. Two alternative geochemical processes have been proposed to dissolve carbonates at depth: hydrogen sulfide oxidation to sulfuric acid, and metal sulfide precipitation. With the aid of geochemical modeling we show that mixing two warm solutions saturated with carbonate results in a new solution that dissolves limestone. Variations in the proportion of the end-member fluids can also form a supersaturated mixture and fill the cavity with a new generation of carbonate. Mixing is in general more effective in dissolving carbonates than the aforementioned processes. Moreover, mixing is consistent with the wide set of textures and mineral proportions observed in cavity infillings.
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CORBELLA I CORDOMÍ, Mercè and AYORA, Carles. Role of fluid mixing in deep dissolution of carbonates. Geologica Acta. 2003. Vol. 1, num. 4, pags. 305-313. ISSN 1695-6133. [consulted: 16 of June of 2026]. Available at: https://hdl.handle.net/2445/16888