Lamb claims Occurrence (Nos. 1-6), Valdez Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Lamb claims Occurrence (Nos. 1-6)	Occurrence
Valdez Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Location: The Lamb claims occurrence is on a steep slope between 5,500 and 6,000 feet elevation. It is about one-quarter mile north-northwest of peak 6440 in the NW1/4NW1/4 section 17, T. 18 S., R. 5 E., Fairbanks Meridian. The occurrence corresponds to locality 14 of Cobb (1979 [OFR 79-238]) and to a malachite location reported by Smith and others (1975). It also corresponds to locality A3 of Kurtak and others (1992). The location is probably accurate within one-quarter mile.
Geology: Rock at the occurrence consists mainly of pegmatite and amphibolite gneiss (Nokleberg and others, 1981). Chalcopyrite, molybdenite, and possibly an unidentified tungsten mineral are sparsely disseminated in the pegmatite and gneiss. Malachite is locally abundant as fracture coatings on weathered amphibolite (Smith and others, 1975; Cobb, 1979 [OFR 79-238]). The rocks are locally iron stained from oxidation of sulfides or possibly biotite. The locality was sampled by the U.S. Bureau of Mines (Kurtak and others, 1992). Sample 1682 of biotite gneiss containing disseminated chalcopyrite assayed 0.5 percent copper and contained slightly anomalous amounts of gold (145 parts per billion) and silver (2.5 parts per million [ppm]); it also contained 170 ppm tungsten. A molybdenite-bearing granite gneiss (sample 618) contained 0.17 percent molybdenum. Intrusion of the pegmatite, regional metamorphism of amphibolite, and introduction of metallic minerals probably occurred in the Late Cretaceous or early Tertiary (Nokleberg and others, 1981).
Workings: The area has been mapped and sampled, but there are no substantial physical workings.
Age: Probably Late Cretaceous or Early Tertiary, the age of intrusion and metamorphism of the Maclaren complex (Nokleberg and others, 1981).

Commodities (Major) - Cu; (Minor) - Mo, W
Development Status: None
Deposit Model: Porphyry Cu-Mo (Cox and Singer, 1986; model 21a).

Other Databases

Link to USGS - Alaska:	MH027

Other Regions, Features and Areas containing this locality

References