|Quadrangle map, 1:250,000-scale||CR|
|Quadrangle map, 1:63,360-scale||C-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This occurrence is about 0.3 mile southwest of the center of Jarvis Island in the NW1/4 section 31, T. 73 S., R. 85 E. The location is accurate.|
Geologic descriptionSainsbury (1961) identified chalcopyrite in recrystallized limestone, and chalcopyrite, pyrrhotite, and pyrite in quartz veinlets in skarn at the contact of a quartz diorite body that intrudes the Ordovician and Silurian Descon Formation. Sainsbury mapped the intrusion as Cretaceous but it probably is part of the large pluton to the northwest across Twelvemile Arm, which has recently been dated as Devonian (S.M. Karl, oral communication, 2003). Maas and others (1991) took two samples of skarn that contained negligible metal values.
|Geologic map unit||(-132.556303538945, 55.5027189623232)|
|Mineral deposit model||Skarn with quartz veinlets.|
|Age of mineralization||Probably related to the contact zone of a Devonian (?) granitic intrusion.|
|Alteration of deposit||Skarn developed at contact of a Devonian (?) granitic intrusion.|
|Workings or exploration||Only limited surface sampling by government geologists.|
|Indication of production||None|
Additional commentsThis occurrence is on land that has been conveyed to the Sealaska Corporation, who hold the surface and subsurface rights, or the land is under application for transfer to them.
Cobb, E. H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Craig quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-869, 262 p.
Maas, K.M., Bittenbender, P E., and Still, J.C., 1995, Mineral investigations in the Ketchikan mining district, southeastern Alaska: U.S. Bureau of Mines Open-File Report 11-95, 606 p.
Maas, K.M., Still, J.C., Clough, A.H., and Oliver, L.K., 1991, Mineral investigations in the Ketchikan mining district, Alaska, 1990: southern Prince of Wales Island and vicinity: U.S. Bureau of Mines Open-File Report 33-91, 139 p., 12 sheets, scale 1:63,360.
|Reporters||D.J. Grybeck (Applied Geology)|
|Last report date||5/1/2004|