|Quadrangle map, 1:250,000-scale||EA|
|Quadrangle map, 1:63,360-scale||A-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is at an elevation of about 2,600 feet on a ridge about 2.6 miles southeast of the old town of Franklin. The occurrence is in section 8, T. 27 N., R. 19 E., of the Copper River Meridian. The location is accurate.|
Geologic descriptionThe rocks in the vicinity of this occurrence are interlayered Paleozoic amphibolite-facies paragneiss, schist, amphibolite, orthogneiss, and minor marble that have been intruded by small Jurassic plutons and dikes (Werdon and others, 2001). The Jurassic igneous rocks are generally white, fine-grained, aplitic- to graphic-textured granite dikes, but they transition westward into a tan, fine- to medium-grained, equigranular, biotite granite. Both the white and tan granites are cut by stockwork milky, quartz veins. Most quartz veins do not contain visible sulfides, but many of the white granites contain as much as 2 percent disseminated limonite (pseudomorphs after pyrite?). Calc-silicate skarn float is present above the intrusions; it contains pyrrhotite, pyrite, and an unknown silver-gray mineral (hematite or molybdenite?); ore samples contain 120 ppm tungsten. An iron-stained, color-banded quartzite (or former quartzose gneiss?) with pyrite(?) or pyrrhotite along fracture surfaces contains 45 ppm molybdenum and 212 ppm zinc; a quartzite or hornfels with iron-sulfides and unknown silver-gray mineral contains 26 ppm molybdenum, 276 ppm lead, and 550 ppm zinc (Werdon and others, 2000).
|Geologic map unit||(-141.722085814342, 64.1356740620719)|
|Mineral deposit model||Pb-Zn skarn.|
|Age of mineralization||Probably related to a Jurassic pluton.|
|Alteration of deposit||Hornfelsing and the development of a calc-silicate skarn on the margin of the pluton.|
|Indication of production||None|
Werdon, M.B., Newberry, R.J., and Szumigala, D.J., 2001, Bedrock geologic map of the Eagle A-2 quadrangle, Fortymile mining district, Alaska: Alaska Division of Geological and Geophysical Surveys Preliminary Interpretive Report 2001-3b, 1sheet, scale 1:63,360.
Werdon, M.B., Szumigala, D.J., Newberry, R.J., Grady, J.C., and Munly, W.C., 2000, Major oxide, minor oxide, trace element, rare-earth element, and geochemical data from rocks collected in Eagle and Tanacross quadrangles, Alaska in 2000: Alaska Division of Geological and Geophysical Surveys Raw-Data File 2000-4, 27 p., 3 sheets, scale 1:63,360.
|Last report date||5/1/2002|