Mt. Ogden

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Mo
Other commodities Au; Pb; W; Zn
Ore minerals arsenopyrite; galena; gold; molybdenite; scheelite; sphalerite
Gangue minerals fluorite; quartz; rhodochrosite

Geographic location

Quadrangle map, 1:250,000-scale TR
Quadrangle map, 1:63,360-scale B-5
Latitude 58.4374
Longitude -133.397
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the west flank of Mount Ogden near the international boundary. It is just under about the center of the north side of section 5, T.40 S., R.73 E. of the Copper River Meridian. This is location T006 of Wells and others (1986). The location is accurate within 1/2 mile.

Geologic setting

Geologic description

The Mount Ogden prospect is in a diorite porphyry stock that covers an area about 4,500 feet by 6,900 feet in size. The stock is marked by sericitic, potassic and chloritic alteration. Molybdenite occurs as sparsely disseminated crystals in the porphyry, in miarolitic cavities in the porphyry, along fractures, in quartz breccia bodies, and in quartz veins. Minor scheelite, fluorite, rhodochrosite, arsenopyrite, sphalerite, galena and gold are present (Wells and others, 1986). Most of this deposit is located on the Canadian side of the international boundary, where it is known as the Nan prospect (Miller and others, 1997). The U.S. Bureau of Mines describe the Mount Ogden prospect as an alaskite intrusive with molybdenite in stockworks, veins, and along fractures (Clough, 1990). Investigations on the Canadian portion of the deposit describe molybdenite clots and fracture coatings that are restricted to aplite dikes and hydrothermally altered felsite (Miller and others, 1997). U-Pb dates from a quartz monzonite porphyry on Mt. Eriksen in British Columbia give an age of 53.5 Ma. A K/Ar date on a biotite-rich, molybdenite-bearing granite dike at the nearby Boundary Creek 2, molybdenum occurrence (TR003) is 59.7 Ma (Miller and others, 1997).
Geologic map unit (-133.398732388472, 58.4370863139216)
Mineral deposit model Porphyry Mo (Cox and Singer, 1986; model 21b)
Mineral deposit model number 21b
Age of mineralization U-Pb dates from a quartz monzonite porphyry on Mt. Eriksen in British Columbia give an age of 53.5 Ma. A K/Ar date on a biotite-rich, molybdenite-bearing granite dike at the nearby Boundary Creek 2, molybdenum occurrence (TR003) is 59.7 Ma (Miller and others, 1997).
Alteration of deposit Sericitic, potassic, and chloritic alteration is present (Wells and others, 1986).

Production and reserves

Indication of production None

References