Unnamed Occurrence (ARDF - MH088; east of Maclaren Glacier), Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - MH088; east of Maclaren Glacier)	- not defined -
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Location: This occurrence is on the east side of the Maclaren Glacier valley at about 4,250 feet elevation, in the SE1/4 section 25, T. 19 S., R. 6 E., Fairbanks Meridian. The location is approximate; it corresponds to locality A6 of Kurtak and others (1992), who gave a range of elevation of between 4,000 and 4,500 feet. The location is probably accurate within a quarter of a mile.
Geology: The rocks near the occurrence are schist, argillite, and slate of late Paleozoic protolith age (Nokleberg and others, 1991). Quartz-ankerite veins about 0.2 foot wide cut across the metamorphic structure. Quartz veins, as much as 0.3 foot wide, in zones as much as 30 feet thick, parallel schistosity. Sulfides are sparse; the rocks are locally stained with malachite, suggesting that chalcopyrite occurs locally in the quartz-ankerite veins (Kurtak and others, 1992, p. 92). Quartz and quartz-ankerite veins contain small concentrations of metals. Of six total samples collected at the site, five contained from 2 to 3 parts per million (ppm) silver; a malachite-stained quartz-carbonate vein contained 276 ppm copper and 80 parts per billion (ppb) gold. Another quartz vein contained 185 ppb gold. Antimony is slightly enriched; three of the six samples contain from 20 to 45 ppm antimony (Kurtak and others, 1992).
Workings: There are no workings. The veins were discovered during U.S. Bureau of Mines study of the area (Kurtak and others, 1992).
Age: Late Paleozoic or younger; possibly related to Cretaceous regional metamorphism (Nokleberg and others, 1982).
Alteration: Oxidation of iron- and copper-bearing minerals.

Commodities (Major) - Ag, Au; (Minor) - Cu, Sb
Development Status: None
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).

Other Databases

Link to USGS - Alaska:	MH088

Other Regions, Features and Areas containing this locality

References