|
West Shasta - Balaklala, Shasta King, Keystone, Iron Mountain. East Shasta - Bully Hill, Rising Star |
|
|
California, USA |
| Main commodities:
Cu Zn S
|
|
 |
|
|
 |
Super Porphyry Cu and Au
|
IOCG Deposits - 70 papers
|
All papers now Open Access.
Available as Full Text for direct download or on request. |
|
|
The West Shasta district of northern California, USA hosts a linear belt of small massive sulphide bodies hosted by the early Devonian Balaklala Rhyolite (a high silica dacite) and underlain by the Copley Greenstone (basaltic andesite) which belong to the Palaeozoic basement rocks of the Klamath Mountains.
The massive sulphides are lensoid masses overlying domes, flows and proximal breccia of the Balaklala Rhyolite comprising predominantly pyrite with lesser quartz, chalcopyrite, sphalerite and rare galena.
The largest deposit was at Iron Mountain, which before it was split into five separate bodies by faulting, represented a single 1375 m long body with 23 Mt of massive sulphide ore.
Other deposits/mines in the district include: Balaklala, Shasta King, Keystone and Mammoth.
The East Shasta district is located some 15 to 30 km to the east and northeast of the West Shasta deposits. It includes a number of small volcanic hosted base metal deposits, the largest of which, Bully Hill and Rising Star accounted for 78% of the districts production, and yielded approximately 23 000 tonnes of copper, 12 000 tonnes of zinc, 70 tonnes of silver and 1 tonne of gold from 0.58 Mt of ore. The much smaller Copper City deposit produced 250 tonnes of high grade copper-silver-gold ore.
These deposits are hosted predominantly by the Permian Bully Hill Rhyolite which overlies a thicker andesite unit also of Permian age, and is overlain by a mafic volcanic unit. Ore occurs as massive and semi-massive sulphides with, in decreasing order of abundance, sphalerite, barite, pyrite, galena, chalcopyrite, tetrahedrite and traces of bornite and pyrrhotite.
For detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2000.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
|
|
|
|
Albers J P 1985 - Geology of the Brick Flat massive Sulfide body, Iron Mountain cluster, West Shasta district, California: in Econ. Geol. v80 pp 2092-2099
|
Albers J P, Bain J H C 1985 - Regional setting and new information on some critical geologic features of the West Shasta district, California: in Econ. Geol. v80 pp 2072-2091
|
Casey W H, Taylor B E 1982 - Oxygen, Hydrogen and Sulfur isotope geochemistry of a portion of the west Shasta Cu-Zn district, California: in Econ. Geol. v77 pp 38-49
|
Gustin M M, Eastoe C J 2000 - Geology and ore petrography of Permian Kuroko-type volcanogenic massive Sulfide deposits of the Bully Hill area, east Shasta district, California: in Econ. Geol. v95 pp 343-360
|
Howe S S 1985 - Mineralogy, textures, and relative age relationships of massive Sulfide ore in the West Shasta district, California: in Econ. Geol. v80 pp 2114-2127
|
Lapierre H, Cabanis B, Coulon C, Brouxel, Albarede F 1985 - Geodynamic setting of Early Devonian Kuroko-type Sulfide deposits in the eastern Klamath Mountains (northern California) inferred by the petrological and geochemical characteristics of the associated island-arc volcanic rocks: in Econ. Geol. v80 pp 2100-2113
|
Lindberg P A 1985 - A volcanogenic interpretation for massive sulfide origin, West Shasta district, California: in Econ. Geol. v80 pp 2240-2254
|
Reed M H 1984 - Geology, wall-rock alteration, and massive sulfide mineralization in a portion of the west Shasta District, California: in Econ. Geol. v79 pp 1299-1318
|
South B C, Taylor B E 1985 - Stable isotope geochemistry and metal zonation at the Iron Mountain mine, West Shasta district, California: in Econ. Geol. v80 pp 2177-2195
|
|
Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
|
Top | Search Again | PGC Home | Terms & Conditions
|
|
