|Quadrangle map, 1:250,000-scale||BC|
|Quadrangle map, 1:63,360-scale||A-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Swennings Greenpoint mineral occurrence is in Section 33 above Greenpoint Glacier at an elevation of about 4200 feet (Berg and others, 1977, p. 92; Elliott and Koch, 1981, p. 13, loc. 36). This location is accurate to within about a quarter of a mile.|
The country rocks in the area of this occurrence are pelitic metasedimentary strata of the Jurassic or older Mesozoic Hazelton Group, which are underlain and locally intruded by the Triassic Texas Creek Granodiorite; and the Eocene Hyder Quartz Monzonite, which intrudes the Hazelton and Texas Creek rocks (Smith, 1977; Berg and others, 1977, p. 15-17, 22-23; Koch, 1996).
The deposit consists of quartz veins in Hazelton hornfels about 50 feet from the contact of a dike of Hyder Quartz Monzonite (Berg and others, 1977, p. 92-93). The veins, which strike N 30 W and dip 65-70 NE, are iron stained and contain scattered knots of galena and molybdenite. Assays of samples collected in 1972 by the U.S. Bureau of Mines showed as much as 100 ppm Ag, 350 ppm Cu, 4.5 percent Pb, 1000 ppm Zn, and 2000 ppm Mo.Lead-isotope studies of galena from the Swennings Greenpoint occurrence (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||(-130.265705060052, 56.0146886749071)|
|Mineral deposit model||Polymetallic veins (Cox and Singer, 1986; model 22c).|
|Mineral deposit model number||22c|
|Age of mineralization||Lead-isotope studies of galena from the Swennings Greenpoint occurrence (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 of quartz veins.|
|Workings or exploration||Assays of samples collected in 1972 by the U.S. Bureau of Mines (Berg and others, 1977) showed as much as 100 ppm Ag, 350 ppm Cu, 4.5 percent Pb, 1000 ppm Zn, and 2000 ppm Mo.|
|Indication of production||None|
Claims were inactive in 1973.Site is in Misty Fiords National Monument.
Berg, H.C., Elliott, R.L., Smith, J.G., Pittman, T.L., and Kimball, A. L., 1977, Mineral resources of the Granite Fiords Wilderness Study Area, Alaska, with a section on aeromagnetic data by Andrew Griscom: U.S. Geological Survey Bulletin 1403, 151 p.
|Reporters||H. C. Berg (Fullerton, California)|
|Last report date||5/17/1998|