Boundary; Boundary Glacier Prospect, Haines, Alaska, USAi

Regional Level Types
Boundary; Boundary Glacier Prospect	Prospect
Haines	City Borough
Alaska	State
USA	Country

Location: This prospect is on and immediately to the east of the Alaska-Canada border, 1.75 miles south of Mt. Henry Clay at 5,700 to 6,000 feet in elevation. It is shown as numbers 116 to 121 by Still and others (1984); numbers 247 and 248 of Still and others (1987); and site P by Gilbert and Redman (1989).
Geology: Still and others (1991) describe this prospect as: 'Narrow bands of iron-stained metasedimentary rocks and altered metabasalt that crop through glacial ice.' 'Float and bedrock samples of sedimentary and volcanic rocks contain up to 0.034 ppm gold, 1.214 ppm silver, 280 ppm zinc, 1,390 ppm copper, 390 ppm cobalt, 400 ppm arsenic, and 200 ppm nickel.' 'A barite rich band hosted in white phyllite contained 47% barium.' Rubicon Minerals (1998) in an unpublished Executive Summary, cites work by Kennecott Alaska Exploration that describes Boundary as: '...quartz-sericite-pyrite schist and felsite with chalcopyrite.' Rubicon also cites Kennecott samples with maximum values of 6.5% copper, 16 ppm lead, 3,610 ppm zinc, 12 ppm silver, and 1.980 ppm gold. Sample descriptions from Still and others (1984) mention phyllite, white phyllite, sericite schist, greenstone and quartzite. These rock types are similar to those at baritic massive sulfide prospects like the Main Zone/Palmer (SK066) and RW Zone (SK067) deposits, and Rubicon Minerals (1998) considers Boundary to be a volcanogenic massive-sulfide system. The phyllitic rocks may reflect a felsic volcanic or altered mafic volcanic protolith. If Boundary is a volcanogenic massive sulfide system correlative with the Windy Craggy deposit in Canada and the Greens Creek deposit on Admiralty Island, then this prospect and others like it in the Mt. Henry Clay area are probably Late Triassic (Still, 1984 [OF 118-84]; Newberry and others, 1997).
Age: If Boundary is a volcanogenic massive-sulfide deposit correlative with the Windy Craggy deposit in Canada and the Greens Creek deposit on Admiralty Island, then this prospect and others like it in the Mt. Henry Clay area are probably Late Triassic (Still, 1984 [OF 118-84]; Newberry and others, 1997).
Alteration: Quartz-sericite (?).

Commodities (Major) - Barite, Cu; (Minor) - As, Co, Zn
Development Status: None
Deposit Model: Besshi- or Kuroko-type massive sulfide (?) (Cox and Singer, 1986; models 28a? o

Other Databases

Link to USGS - Alaska:	SK057

Other Regions, Features and Areas containing this locality

References