Webfoot; Reed and Fiske; Grimes Prospect, Willow Creek Mining District, Matanuska-Susitna Borough, Alaska, USAi

Regional Level Types
Webfoot; Reed and Fiske; Grimes Prospect	Prospect
Willow Creek Mining District	Mining District
Matanuska-Susitna Borough	Borough
Alaska	State
USA	Country

Capps (1915) refers to Webfoot or area very near Webfoot as the Grimes prospect and Katz (1911) uses the name Reed and Fiske.
Location: On west side of upper Archangel Creek, marked with adit symbol and labeled 'Webfoot Prospect' on the Anchorage D-6 1:63,360-scale topographic map. Accurate within 400 ft. Locality 20 from Cobb (1972) and locality 17 of MacKevett and Holloway (1977).
Geology: A 2.5 to 5 ft wide auriferous quartz vein cuts the Late Cretaceous Willow Creek Pluton. The vein strikes due north and dips 33 to 40 W (Ray, 1954). Malachite staining was noted on some the quartz in dump (Capps, 1915). Kurtak (1986) reported that a 2.5-ft-wide chip sample across a quartz vien on the edge of a stope contained 0.44 ppm (0.013 oz/ton) Au, while a surface exposure contained 0.21 ppm ( 0.006 oz/ton) Au. The Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).
Workings: Vein explored by open cuts and about 300 ft of underground drifts. The ore is reported to be a large tonnage of low-grade material (Ray, 1954). Kurtak (1986) reported that a 2.5-ft-wide chip sample across a quartz vien on the edge of a stope contained 0.44 ppm (0.013 oz/ton) Au, while a surface exposure contained 0.21 ppm ( 0.006 oz/ton) Au.
Age: Late Cretaceous or younger; vein cuts the Late Cretaceous Willow Creek Pluton.
Alteration: Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954). Sericitic alteration on vein margins (Kurtak, 1986).
Production: No record of production (Cobb, 1972).

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

Other Databases

Link to USGS - Alaska:	AN047

Other Regions, Features and Areas containing this locality

References