|Quadrangle map, 1:250,000-scale||SK|
|Quadrangle map, 1:63,360-scale||B-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||
These occurrences are centered on a point approximately 2.8 miles, S70E from the village of Klukwan at an elevation of about 1,900 feet. This point is midway between two steep southwest flowing drainages in the SE1/4, section 4, T. 29 S., R. 57 E. of the Copper River Meridian. The location defines the approximate center of a group of anomalously high samples collected by Gilbert and others (1991). Their sample sites 778 to 780 on sheet 2 are in the more westerly drainage and sample sites F113 to F117 on sheet 1 are in the more easterly drainage. Samples F110 to F112 plot along or near the ridgetop between the two drainages.The area has been informally called 'Nineteenmile Ridge' by Still and others (1991) who reference the sample sites of Gilbert and others (1991). However, Still and others (1991) also refer to this site as being on the west slope of Tukago (Tukgahgo?) Mountain, which is about 9 miles to the southeast in the Takshanuk Mountains. The reference to 'Tukago' Mountain is probably an error.
Geologic descriptionThe following information is summarized from Gilbert and others (1991). Several float and bedrock samples at this site were collected from two steep drainages and along or near the ridgetop between the two drainages. The samples are mostly diorite, granodiorite and hornblende diorite with both primary and secondary copper minerals. The secondary copper minerals often occur as coatings along fractures. Samples contain up to 38,400 ppm copper, 18.90 ppm silver, and 2.43 ppm gold. The samples were collected about 3.4 miles southeast of the center of the Cretaceous, Klukwan zoned-ultramafic complex (SK030). The samples come from the outer dioritic phase of the zoned complex (Gilbert and others, 1987; MacKevett and others; 1974).
|Geologic map unit||(-135.82184989173, 59.3796686043542)|
|Mineral deposit model||Only an occurrence with little information; it appears to be primary copper sulfides in the outer dioritic phase of a zoned ultramafic complex, with secondary copper minerals along joints (Cox and Singer, 1986; model 9).|
|Mineral deposit model number||9|
|Age of mineralization||Cretaceous or younger based on age of the Klukwan ultramafic complex (MacKevett and others, 1974).|
|Indication of production||None|
Additional commentsThese occurrences are within one mile of the Alaska, Chilkat Bald Eagle Preserve.
Gilbert, W.G., Burns, L.E., Redman, E.C., and Forbes, R.B., 1987, Preliminary bedrock geology and geochemistry of the Skagway B-3 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 87-2, 2 sheets, scale 1:36,200.
Gilbert, W.G., Still, J.C., Burns, L.E., Wier, K.R., and Redman, E.C., 1991, Geochemistry of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-5, 75 p., 2 sheets, scale 1:63,360,
MacKevett, E.M., Jr., Robertson, E.C., and Winkler, G.R., 1974, Geology of the Skagway B-3 and B-4 quadrangles, southern Alaska: U.S. Geological Survey Professional Paper 832, 33 p., 1 plate.
Still, J.C., 1991, Section A: Haines - Klukwan - Porcupine subarea, in U.S. Bureau of Mines, Mineral investigations in the Juneau Mining District, Alaska, 1984-1988: Volume 2 - Detailed mine, prospect, and mineral occurrence descriptions: U.S. Bureau of Mines Special Publication VOL. 2A, 214 p., 9 sheets.
Still, J.C., Hoekzema, R.B., Bundtzen, T.K., Gilbert, W.G., Wier, K.R., Burns, L.E., and Fechner, S.A., 1991, Economic geology of Haines-Klukwan-Porcupine area, southeastern Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 91-4, 156 p., 5 sheets, scale 1:63,360.
|Reporters||T.C. Crafford (T. Crafford & Associates, Anchorage)|
|Last report date||2/4/2001|