2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM
Paper No. 141-23
Presentation Time: 8:00 AM-4:45 PM

Origin of Hydrothermal Fluids of the Shallow Submarine Vents of Bahía Concepción, Mexico: An Approach by Geochemical Modeling

VILLANUEVA ESTRADA, Ruth Esther1, PROL LEDESMA, Rosa María1, RODRÍGUEZ DÍAZ, Augusto Antonio2, GONZÁLEZ PARTIDA, Eduardo3, CANET, Carles1, and TORRES ALVARADO, Ignacio Salvador4, (1) Recursos Naturales, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, México D.F, México city, 04510, Mexico, ruth@geofisica.unam.mx, (2) Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, México D.F, México City, 04510, Mexico, (3) Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Juriquilla, Querétaro, 76230, Mexico, (4) Centro de Investigación en Energía, Universidad Nacional Autónoma de México, A.P. 34, Temixco, Morelos, 62580, Mexico

We use geochemical modeling to explain the origin of the fluids discharged in the submarine zone of Bahía Concepción, Baja California Sur, Mexico. The geochemical model was performed using REACT program of the computational program Geochemistxs Workbench (release 6.0). The program was executed assuming a polythermal path and a closed system. The selection of the components is based upon fluid inclusions measurements from veins that crop out around the vent discharges. These components are: (a) deep fluid of meteoric origin, (b) high salinity water trapped in the sediments, and (c) seawater. The first mix was between deep fluids with a high salinity fluid. The calculated chemical composition of such fluid fits to a thermal end-member, which mixes with seawater immediately before to be discharged. The fluid obtained by chemical modeling shows calcium, chloride and silica concentrations similar to those of the vent discharges, and salinity and density similar to those calculated from the fluid inclusions study. Geochemical modeling shows that at least three major water components mix in different proportions before the fluid is discharged. Approximately the thermal end-member is composed of 20-30% of the high salinity fluid. The other 70-80% corresponds to a deep fluid that is formed by meteoric water heated by deep penetration. The fluid resultant of the first modeling processes was mixed with seawater and it has a similar chemical composition of the hydrothermal manifestations.

2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM
General Information for this Meeting
Session No. 141--Booth# 23
Geochemistry; Geochemistry, Organic (Posters)
George R. Brown Convention Center: Exhibit Hall E
8:00 AM-4:45 PM, Sunday, 5 October 2008

Geological Society of America Abstracts with Programs, Vol. 40, No. 6, p. 133

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