Hydrothermal alteration facies within the intrusive-hosted Salave gold prospect, NW Spain
The Salave gold prospect occurs within an Hercynian granodioritic complex intruding Cambro-Ordovician metasediments and a heterogeneous gabbroic body. Mineralization consists mostly of disseminated and veinlet pyrite, arsenopyrite, molybdenite, stibnite, and lesser sphalerite associated with a zoned sequence of hydrothermal alteration. Gold occurs as free particles and/or intergrown with the sulfides. Mathematical appraisal of analytical data suggests that the hydrothermal alteration resulted from largely isochemical redistribution processes imposed on the mineralogy of the host granodiorite by influxes of sporadically boiling fluids rich in CO/sub 2/. Hydrothermal alteration is described in terms of a zonal sequence inward from unaltered host rock through (1) chlorite-sericite alteration-(2) propylitic to advanced propylitic alterations-(3)albitites-(4) an auriferous (greater than or equal to 1g/t Au) sericite-carbonate-albite-(+/-)quartz-sulfide cataclastic facies. The zonation corresponds to increasing carbonatization, sericitization, albitization, desilification, and destruction of the original igneous texture. Aventurine alteration is common and is thought to be the product of late stage hydrothermal oxidizing conditions. Potassic alteration in the form of K-feldspar or biotite was occasionally observed.
- Research Organization:
- BP Minerals Ltd., Edinburgh (England)
- OSTI ID:
- 6593661
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GOLD ORES
MINERALIZATION
MINERALOGY
GRANODIORITES
HYDROTHERMAL ALTERATION
SPAIN
CAMBRIAN PERIOD
CHLORITE MINERALS
GABBROS
ORDOVICIAN PERIOD
ROCK-FLUID INTERACTIONS
SULFIDE MINERALS
DEVELOPING COUNTRIES
EUROPE
GEOLOGIC AGES
GRANITES
IGNEOUS ROCKS
MINERALS
ORES
PALEOZOIC ERA
PLUTONIC ROCKS
ROCKS
SILICATE MINERALS
WESTERN EUROPE
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)