Active metasomatism in the Cerro Prieto geothermal system, Baja California, Mexico: a telescoped low pressure/temperature metamorphic facies series
In the Cerro Prieto geothermal field, carbonate-cemented, quartzofeldspathic sediments of the Colorado River delta are being actively metasomatized into calc-silicate metamorphic rocks by reaction with alkali chloride brines between 200/sup 0/ and 370/sup 0/C, low fluid and lithostatic pressures, and low oxygen fugacities. Petrologic investigations of drill cores and cutting from over 50 wells in this field identified a prograde series of calc-silicate mineral zones which include as index minerals: wairakite, epidote, prehnite, and clinopyroxene. Associated divariant mineral assemblages are indicative of a very low pressure/temperature metamorphic facies series which encompasses the clay-carbonate, zeolite, greenschist, and amphibolite facies. This hydrothermal metamorphic facies series, which is becoming increasingly recognized in other active geothermal systems, is characterized by temperature-telescoped dehydration and decarbonation mineral equilibria. Its equivalent should now be sought in fossil hydrothermal systems.
- Research Organization:
- California Univ., Riverside (USA). Inst. of Geophysics and Planetary Physics; Michigan Technological Univ., Houghton (USA). Dept. of Geology and Geological Engineering; Stanford Univ., CA (USA). Dept. of Geology
- DOE Contract Number:
- FC07-80ID12145
- OSTI ID:
- 6011812
- Report Number(s):
- UCR/IGPP-83/6; ON: DE83016725
- Country of Publication:
- United States
- Language:
- English
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Active hydrothermal metamorphism in the Cerro Prieto geothermal system, Baja California, Mexico: a telescoped low P/T facies series. [Abstract only]
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Related Subjects
150202* -- Geology & Hydrology of Geothermal Systems-- Non-USA-- (-1989)
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
AMPHIBOLITES
CALCIUM COMPOUNDS
CALCIUM SILICATES
CERRO PRIETO GEOTHERMAL FIELD
CLAYS
DRILL CORES
EPIDOTES
GEOLOGY
GEOTHERMAL FIELDS
Geothermal Legacy
HYDROTHERMAL ALTERATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON COMPOUNDS
IRON SILICATES
MATERIALS
METAMORPHIC ROCKS
METAMORPHISM
MINERALOGY
MINERALS
OXYGEN COMPOUNDS
PETROLOGY
ROCKS
SCHISTS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
WAIRAKITE
WATER WELLS
WELLS
ZEOLITES