Relationship of grade, tonnage, and basement lithology in volcanic-hosted epithermal precious-and base-metal quartz-adularia-type districts

Mining Geology
By: , and 

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Abstract

Examination of grades, tonnages, and basement rocks for 88 epithermal precious- and base-metal quartz-adularia-type districts in North, Central, and South America, and Japan reveals that the type of basement rock below the mineralized veins is useful for predicting grade and size of deposits. Epithermal districts overlying basement with salt and evaporites, or rocks with trapped sea water, have a median tonnage (production and reserves) of 1.4 million metric tons and median grades of 1.5g/t Au, 130g/t Ag, 2.5%Pb, 1.7%Zn, and 0.16%Cu. Districts overlying sedimentary basements have a median tonnage of 0.77 million metric tons and median grades of 7.5g/t Au, 110g/t Ag, <0.025%Zn, <0.005%Cu, and <0.001%Pb. Districts overlying igneous basements have a median tonnage of 0.3 million metric tons and median grades of 5.9g/t Au, 38g/t Ag, <0.25%Zn, <0.002%Cu, and <0.003%Pb. This investigation suggests that basement rocks affect vein components in epithermal precious- and base-metal quartz-adularia-type deposits.

Publication type Article
Publication Subtype Journal Article
Title Relationship of grade, tonnage, and basement lithology in volcanic-hosted epithermal precious-and base-metal quartz-adularia-type districts
Series title Mining Geology
DOI 10.11456/shigenchishitsu1951.36.245
Edition 264
Volume 36
Issue 245
Year Published 1986
Language English
Publisher J-STAGE
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 20 p.
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