Coastal submarine hydrothermal activity off northern Baja California

Journal Article · Mon Apr 10 00:00:00 EST 1978 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB083iB04p01757· OSTI ID:6933005

Vidal, V M.V.; Vidal, F V; Isaacs, J D; Young, D R

In situ observations of submarine hydrothermal activity have been conducted in Punta Banda. Baja Califronia, Mexico, approximately 400 m from the coast and at a seawater depth of 30 m. The hydrothermal activity occurs within the Agua Blanca Fault, a major transverse structure of Northern Baja California. Hot springwater samples have been collected and analyzed. Marked differences exist between the submarine hot springwater, local land hot springwaters, groundwater, and local seawater. SiO/sub 2/, HCO/sub 3/, Ca, K, Li, B, Ba, Rb, Fe, Mn, As, and Zn are enriched in the submarine hot springwater, while Cl, Na, So/sub 4//sup 2/, Mg, Cu, Ni, Cd, Cr, and perhaps Pb are depleted in relation to average and local seawater values. Very high temperatures, at the hydrothermal vents, have been recorded (102/sup 0/C at 4-atm pressure). Visible gaseous emanations rich in CH/sub 4/ and N/sub 2/ coexist with the hydrothermal solutions. Metalliferous deposits, pyrite, have been encountered with high concentrations of Fe, S, Si, Al, Mn, Ca, and the volatile elements As, Hg, Sb, and Tl, X ray dispersive spectrometry (1500-ppm detection limit). X ray diffraction, and scanning electron microscopy of the isolated metalliferous precipitates indicate that the principal products of precipitation are pyrite and gypsum accompanied by minor amounts of amorphous material containing Si and Al. Chemical analyses and XRD of the reference control rocks of the locality (volcanics) versus the hydrothermally altered rocks indicate that high-temperature and high-pressure water-rock interactions can in part explain the water chemistry characteristics of the submarine hydrothermal waters. Their long residence time, the occurrence of an extensive marine sedimentary formation, their association with CH/sub 4/ and their similarities with connate waters of oil and gas fields suggest that another component of their genesis could be in cation exchange reactions within deeply buried sediments of marine origin.

• Research Organization: Scripps Institution of Oceanography, La Jolla, California 92093
• OSTI ID: 6933005
• Journal Information: J. Geophys. Res.; (United States), Vol. 83:B4
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
SEA BED
HYDROTHERMAL SYSTEMS
GEOTHERMAL FLUIDS
GYPSUM
HEAT FLUX
HOT SPRINGS
METHANE
NITROGEN
PYRITES
ROCK-FLUID INTERACTIONS
SEDIMENTS
ALKALINE EARTH METAL COMPOUNDS
ALKANES
CALCIUM COMPOUNDS
CALCIUM SULFATES
CHALCOGENIDES
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
GEOTHERMAL SYSTEMS
HYDROCARBONS
MINERALS
NONMETALS
ORES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SULFATES
SULFIDES
SULFUR COMPOUNDS
SULFUR ORES
THERMAL SPRINGS
580100* - Geology & Hydrology- (-1989)
580500 - Oceanography- (1980-1989)