Evaporites and strata-bound tungsten mineralization
- Unocal Science and Technology Division, CA (USA)
Discoidal gypsum crystal cavities occur in quartzites that host varying amounts of strata-bound scheelite mineralization near Halls Creek in Western Australia. The host quartzites have been regionally metamorphosed to greenschist facies and are contained within a Middle Proterozoic sequence that includes pelites, mafic and felsic volcanics, and volcaniclastic rocks. Textural, fluid inclusion, and oxygen isotope data indicate that scheelite was present in the host quartzites prior to regional metamorphism. The presence of crystal cavities after gypsum in the quartzites implies an evaporitic origin for this sequence. The continental-sabkha playa basins of the Mojave Desert, California, are suggested to be possible modern analogs-e.g., Searles Lake, where the tungsten content is up to 70 ppm WO{sub 3} in brines and 118 ppm in muds, and exceeds the amount of tungsten in all known deposits in the United States. Metamorphism of a continental evaporitic sequence containing tungsten could produce an assemblage of rocks very similar to those reported from several stratabound tungsten deposits. Some of these, such as at Halls Creek, may be related to original accumulations of tungsten in nonmarine evaporitic environments.
- OSTI ID:
- 7014644
- Journal Information:
- Geology; (USA), Vol. 17:2; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
CALIFORNIA
GEOLOGIC DEPOSITS
METAMORPHISM
TUNGSTEN
MINERALIZATION
WESTERN AUSTRALIA
ECOLOGICAL CONCENTRATION
EVAPORITES
GEOLOGIC HISTORY
GEOLOGIC MODELS
ORIGIN
AUSTRALASIA
AUSTRALIA
ELEMENTS
FEDERAL REGION IX
METALS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
TRANSITION ELEMENTS
USA
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences