ALMOST THERE!. Help us with a final push needed to keep running. Click here to help.
Catawiki are hosting a benefit auction. All proceeds to! BID NOW
Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat Articles
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Unnamed Occurrence (ARDF - ID146; near hill 2825 on Granite Mountain), Iditarod District, Yukon-Koyukuk Borough, Alaska, USA

This page is currently not sponsored. Click here to sponsor this page.
Location: This occurrence is at an elevation of about 2,600 feet, about 0.7 mile southwest of peak 2923, the top of Granite Mountain. It is about 0.3 mile north of the center of section 29, T. 26 N., R. 40 W., of the Seward Meridian. The location is accurate.
Geology: This occurrence, also referred to as the Granite Mountain prospect (Bundtzen and Miller, 1997) consists of several sizable bodies of metasomatic axinite, anatase, and tourmaline at the contact between the Granite Mountain pluton and hornfelsed rocks derived from the Upper cretaceous Kuskokwim Group. The occurrence includes: 1) zones of tourmaline-bearing sheeted veins, 2) tourmaline-cemented breccias in hornfels; and 3) axinite-tourmaline-sulfide replacement bodies in both intrusive rocks and in hornfels. The nearby Granite Mountain pluton has a 40K/40Ar age of 62.6 Ma (Bundtzen and Miller, 1997). One large area of boron-rich tourmaline-axinite-anatase greisen is 1,300 feet long, about 50 feet wide, and cylindrical in cross section; it may contain 5.5 million tons of boron-enriched material of unknown grade. This zone also contains disseminated gray sulfide minerals. Grab samples from the occurrence contained 100 parts per million (ppm) tin, 500 parts per billion (ppb) silver, 50 ppb gold, 9.0 ppm bismuth, 28 ppm antimony, 80 ppm arsenic, and more than 2,000 ppm boron (McGimsey and others, 1988; Bundtzen and Miller, 1997).
Workings: Samples were collected by the U.S. Geological Survey and Alaska Division of Geological and Geophysical Surveys in 1984 (McGimsey and others, 1988; Bundtzen and Miller, 1997).
Age: The nearby Granite Mountain pluton has a A 40K/40Ar age of 62.6 Ma (Bundtzen and Miller, 1997).
Alteration: Development of axinite-tourmaline-quartz greisen.

Commodities (Major) - Ag, Sn; (Minor) - As, Au, Bi, Sb
Development Status: None
Deposit Model: Sn-polymetallic deposit or Polymetallic vein (Cox and Singer, 1986; model 20b o

Mineral List

4 entries listed. 2 valid minerals.

The above list contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286. McGimsey, R.G., Miller, M.L., and Arbogast, B.F., 1988, Paper version of analytical results, and sample locality map for rock samples from the Iditarod quadrangle, Alaska: U.S. Geological Survey Open-File Report 88-421-A, 110 p., 1 sheet, scale 1:250,000. Miller, M.L., and Bundtzen, T.K., 1994, Generalized geologic map of the Iditarod quadrangle, Alaska showing potassium-argon, major oxide, trace element, fossil, paleocurrent, and archeological sample localities: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-A, 48 pages; 1 sheet, scale 1:250,000. Miller, M.L., Bundtzen, T.K., and Gray, J.E., 2005, Mineral resource assessment of the Iditarod quadrangle, west-central Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-2219-B, scale 1:250,000, pamphlet.

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2018, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: December 13, 2018 13:21:12 Page generated: January 19, 2015 21:07:27
Go to top of page