Marmot, upper basin

Prospect, Inactive

Commodities and mineralogy

Main commodities Ag; Cu; Mo; Pb
Other commodities Au; Zn
Ore minerals chalcopyrite; galena; molybdenite; pyrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale BC
Quadrangle map, 1:63,360-scale A-2
Latitude 56.026
Longitude -130.369
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Marmot upper basin prospect (Berg and others, 1977, p. 106) is in Section 26 on the southeast side of Banded Mountain at an elevation of about 4600 to 4750 feet. This location is accurate to within about a quarter of a mile.

Geologic setting

Geologic description

The country rocks in the general area of this prospect (Berg and others, 1977, p. 15-18, 22; Koch, 1996) are banded variegated pelitic hornfels, phyllite, and fine-grained schist of the Jurassic or older Mesozoic Hazelton Group. The metasedimentary rocks are intruded by andesite dikes that may be apophyses of the Triassic Texas Creek Granodiorite, and by aplite dikes that may be apophyses of Eocene Hyder Quartz Monzonite.
The mineral deposit (Berg and others, 1977, p. 100, 106, 110, 112; Elliott and Koch, 1981, p. 9, loc. 19) consists of a stockwork(?) of quartz [-calcite] veins up to about 3 feet thick in locally iron-stained dark pelitic hornfels of the Hazelton Group. The veins contain pyrite, chalcopyrite, molybdenite, and galena. The highest assay values reported from vein and hostrock samples collected by the U.S. Bureau of Mines in 1972 were 2000 ppm Mo, 5000 ppm Pb, 3000 ppm Cu, 150 ppm Ag, and 0.1 ppm Au.
Lead-isotope studies of the galena at the Marmot upper basin prospect (Maas and others, 1995, p. 229-248) indicate that the deposit is Eocene in age, contemporaneous with emplacement of the Hyder Quartz Monzonite.
Geologic map unit (-130.37070559074, 56.0256806716444)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization Lead-isotope studies of the galena at the Marmot upper basin prospect (Maas and others, 1995, p. 229-248) indicate that the deposit is Eocene in age, contemporaneous with emplacement of the Hyder Quartz Monzonite.
Alteration of deposit Local intense iron staining.

Production and reserves

Workings or exploration Highest assay values reported from veins and hostrock samples collected by U.S. Bureau of Mines in 1972 were 2000 ppm Mo, 5000 ppm Pb, 3000 ppm Cu, 150 ppm Ag, and 0.1 ppm Au.
Indication of production None

Additional comments

The Marmot group of 51 claims that were staked in 1969 covered all or parts of the old Jumbo (Banded Mountain) (BC021), Galena (BC022), and Edelweiss (BC023) prospects, which are described separately in this report. The Marmot upper basin prospect area was only recently exposed by retreat of glacial ice. The prospect was active in 1973.
Site is in Misty Fiords National Monument.

References