Webfoot

Prospect, Inactive

Alternative names

Reed and Fiske
Grimes

Commodities and mineralogy

Main commodities Au
Other commodities Cu
Ore minerals gold; malachite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale AN
Quadrangle map, 1:63,360-scale D-6
Latitude 61.811
Longitude -149.246
Nearby scientific data Find additional scientific data near this location
Location and accuracy 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).

Geologic setting

Geologic description

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 vein 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).
Geologic map unit (-149.24821013701, 61.8104716440718)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Late Cretaceous or younger; vein cuts the Late Cretaceous Willow Creek Pluton.
Alteration of deposit 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 and reserves

Workings or exploration 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 vein 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.
Indication of production None
Production notes No record of production (Cobb, 1972).

Additional comments

Capps (1915) refers to Webfoot or area very near Webfoot as the Grimes prospect and Katz (1911) uses the name Reed and Fiske.

References

MRDS Number A011621
Reporters D.P. Bickerstaff (USGS contractor); S.W. Huss (USGS)
Last report date 7/30/1998