USGS Professional Paper 1697 - Alaska Resources Library

238 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera
ene-sphalerite-rich skarn distal to the dike swarm. Garnetrich
skarn grades 0.5 to 1 percent Cu and 1 to 2 oz/t Ag, and
negligible Zn and Pb. Pyroxene-rich skarn generally contains
5-20 percent Zn, 0.1-3 percent Pb, 0.5-2 percent Cu, and 2 to
9 oz/t Ag. In a single outcrop, skarn pyroxene becomes more
Fe-rich, and sulfides increase towards marble. Sulfide veins
occur locally in dikes and wall rocks. Many dikes are lacking
associated skarn, and many dikes possess skarn only along one
contact.The deposit has a resource of an estimated 230,000
tonnes with 16 percent combined Pb and Zn.
Map
Cross section
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Kijik River Porphyry Cu Deposit
The Kijik River porphyry Cu deposit consists of a large
area of low-grade, disseminated chalcopyrite, pyrite, and
minor molybdenite that occur in and adjacent to an early
Tertiary dacite porphyry (Eakins and others, 1978; Nelson
and others, 1985; T.K. Bundtzen, written commun., 1984).
The deposit contains a distinctive orange gossan that extends
over a 3 km 2 area. The gossan contains an extensive stockwork
and zones of sericite and silicic alteration and sulfides.
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Conglomerate (Tertiary)
Skarn
Hornblende hornfels
Porphyritic quartz
monzodiorite
Quartz monzodiorite to
quartz monzonite
Marble
Northern metabasalt
Southern metabasalt
Fault
Contact
Endoskarn
Metabasalt (altered to endoskarn)
Massive garnet
Garnet-pyroxene skarn
Idocrase-wollastonite skarn
Garnet-pyroxenewollastonite-skarn
Cu sulfides
Magnetite
Quartz diorite (Cretaceous)
Marble (Triassic)
Cretaceous
Triassic
Figure 113. Zackly Cu-Au skarn deposit, southern Alaska metallogenic belt, southern Alaska. Schematic geologic
map and cross section. Adapted from Nokleberg and others (1986) and Newberry and others (1997). See figure 103
and table 4 for location.