|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Bird Beak prospect is at an elevation of about 5,900 feet, about 1,600 feet southwest of peak 6120 and about 0.8 mile west of lower Eureka Glacier. It is in about 0.7 mile northwest of the center of section 34, T. 18 S., R. 7 E., of the Fairbanks Meridian. Bittenbender and others (2007, figure 14) show an aerial view of the prospect.|
The Bird Beak prospect is in an Upper Triassic ultramafic and mafic sill-like complex in fault contact with a Tertiary to Cretaceous composite granitic to dioritic pluton (Nokleberg and others, 1991). Rose (1966) mapped dunite bodies associated with diorite, quartz diorite, and gabbro in this area. Mafic and ultramafic rocks in the Broxson Gulch thrust may have lubricated the footwall of the thrust (Kurtak and others, 1992). The hanging wall of the thrust consists of schist. Olivine metagabbro and serpentinized dunite host the ore minerals at the prospect.
The U.S. Bureau of Mines collected samples of dunite and gabbro from the prospect (Kurtak and others, 1992). Sample 3038 of olivine gabbro with disseminated pyrrhotite and chalcopyrite assayed 0.15 percent copper, 0.21 percent chromium, 0.36 percent nickel, 550 parts per billion (ppb) palladium, and 80 ppb platinum. Sample 2644 of limonite-stained serpentine contained 0.13 percent copper, 896 parts per million (ppm) nickel, 280 ppb palladium, and 570 ppb platinum. A pentlandite(?)-bearing pyroxenite sample assayed 0.2 percent nickel and 25 ppb platinum.
Foley (1992) reported similar values in red, iron-oxide-stained, sulfide-rich, olivine gabbro; microprobe examination of the gabbro showed minute particles of moncheite (PtTe) along grain boundaries between chalcopyrite and ferromagnesian silicate minerals.
Bittenbender and others (2007) sampled the prospect. Their best samples were from a gabbro sill that cuts peridotite. Two selected samples contained up to 167 ppm gold, 462 ppb platinum, 385 ppb palladium, 1,820 ppm copper, and 4,450 ppm nickel. A more representative sample of approximately a 10 by 10 foot area of the gabbro contained 34 ppb gold, 105 ppb platinum, 94 ppb palladium, 592 ppm copper, and 1,815 ppm nickel. They indicate that the mineralization is well exposed but is unlikely to be of significant size.In 2001, the prospect was on claims of the MAN project of Pure Nickel Inc. Pure Nickel sampled the Bird's Beak showing in 2011 and grab samples returned values of 1.39 percent nickel, 0.48 percent copper, and 7.0 grams of platinum group elements + gold + silver per tonne (Pure Nickel Inc., 2011).
|Geologic map unit||(-146.398866482896, 63.3169743826383)|
|Mineral deposit model||Nickel-copper-PGE mineralization in a differentiated mafic-ultramafic complex.|
|Age of mineralization||Probably Late Triassic; synchronous with emplacement of the mafic-ultramafic complex (Nokleberg and others, 1991).|
|Alteration of deposit||All of the ultramafic rock units are moderately to strongly serpentinized (Bittenbender and others, 2007).|
|Workings or exploration||
The prospect was sampled by the U.S. Bureau of Mines (Kurtak and others, 1992) and the Bureau of Land Management (Bittenbender and others, 2007).In 2001, the prospect was on claims of the MAN project of Pure Nickel Inc. Pure Nickel sampled the Bird's Beak showing in 2011 and grab samples returned values of 1.39 percent nickel, 0.48 percent copper, and 7.0 grams of platinum group elements + gold + silver per tonne (Pure Nickel Inc., 2011).
|Indication of production||None|
Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
Foley, J.Y., 1992, Ophiolite and other ultramafic metallogenic provinces in Alaska (west of the 141th meridian): U.S. Geological Survey Open-File Report 92-20-B, 55 p.
Kurtak, J.M., Southworth, D.D., Balen, M.D., and Clautice, K.H., 1991, Mineral investigations in the Valdez Creek Mining District, south-central Alaska: U.S. Bureau of Mines Open-File Report 1-92, 658 p., 2 sheets, scale 1:250,000.
Nokleberg, W.J., Lange, I.M., Roback, R.C., Yeend, Warren, and Silva, S.R., 1991, Map showing locations of metalliferous lode and placer mineral occurrences, mineral deposits, prospects, and mines, Mount Hayes quadrangle, eastern Alaska Range, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1996-C, 42 p., 1 sheet, scale 1:250,000.
Pure Nickel Inc., 2011, Pure Nickel MAN Alaska Exploration Update: http://www.purenickel.com/s/NewsReleases.asp?ReportID=497855 (News release, December 21, 2011, as of December 2, 2014).
|Reporters||W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group); W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS); V.C. Zinno (Alaska Earth Sciences, Inc.)|
|Last report date||12/10/2014|