|Quadrangle map, 1:250,000-scale||TR|
|Quadrangle map, 1:63,360-scale||B-5|
|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 descriptionThe 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).|
|Indication of production||None|
Clough, A.H., 1990, Bureau of Mines mineral investigations in the Juneau mining district, Alaska, 1984-1988, Volume 2, Detailed mine, prospect, and mineral occurrence descriptions, Section E, Coast Range subarea: U.S. Bureau of Mines of Mines Special Publication, 44 p.
Miller, L.D., Goldfarb, R.J., Snee, L.W., McClelland, W.C., and Klipfel, P.D., 1997, Paleocene molybdenum mineralization in the eastern Coast Batholith, Taku River region, and new age constraints on batholith evolution, in Dumoulin, J.A., and Gray, J.E., eds., Geologic studies in Alaska by the U.S. Geological Survey, 1995: U.S. Geological Survey Professional Paper 1574, p. 125-135.
|Reporters||J.C. Barnett and L.D. Miller (Juneau, Alaska)|
|Last report date||11/27/2001|