Role of fluid mixing in deep dissolution of carbonates


Autoria(s): Corbella i Cordomí, Mercè; Ayora, Carles
Contribuinte(s)

Universitat de Barcelona

Data(s)

09/03/2011

Resumo

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.

Identificador

http://hdl.handle.net/2445/16888

Idioma(s)

eng

Publicador

Universitat de Barcelona (UB). Institut de Ciències de la Terra Jaume Almera (ICTJA). Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDEA). Universitat Autonònoma de Barcelona (UAB). Consejo Superior de Investigaciones Científicas (CSIC)

Direitos

(c) Corbella et al., 2003

info:eu-repo/semantics/openAccess

Palavras-Chave #Roques carbonatades #Dipòsits minerals #Geoquímica #Carbonate rocks #Mineral deposits #Geochemistry
Tipo

info:eu-repo/semantics/article