Gladstone

Prospect, Undetermined

Commodities and mineralogy

Main commodities Au; Cu
Ore minerals chalcopyrite; pyrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale A-1
Latitude 55.22538
Longitude -132.07047
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Gladstone property extends over 4 claims. The site is at the northern workings at an elevation of about 150 feet. It is about 0.7 mile east of triangulation station Lancaster and about 0.5 mile west-northwest of the center of section 6, T. 77 S., R. 89 E. The property extends for about a half mile south-southwest to an open cut at an elevation of about 400 feet.

Geologic setting

Geologic description

As originally described by Wright and Wright (1908), the Gladstone deposit consists of several brecciated quartz-calcite veins up to 6 feet thick, exposed over a distance of about a half mile. The veins contain pyrite and chalcopyrite; the host rock is mainly marble with schist layers that is part of the Wales Group of Late Proterozoic and Cambrian age (Eberlein and others, 1983; Brew, 1996). The property extended over four claims and included a tunnel and several open cuts. The deposit was examined by Maas and others (1991) and by Hedderly-Smith (1999 [Inventory]), who reinterpreted it as conformable gold- and copper-bearing breccia zones in carbonate rocks similar to deposits to the south in the Kael-7 Mile Trend (CR188). Maas and others (1991) examined the Gladstone adit, where a 10-foot-wide shear zone is exposed that contains quartz-marble breccia. The shear zone is up to 20 feet wide at the surface. Nine chip samples contained 19 to 190 parts per billion (ppb) gold and 1,742 parts per million (ppm) to 2.05 percent copper. A sample collected by Hedderly-Smith (1999 [Inventory]) across a 6-foot mineralized zone with about 5 percent pyrite and chalcopyrite contained 7,669 ppm copper and 11 ppb Au.
Geologic map unit (-132.072142043504, 55.225024951128)
Mineral deposit model Probably a stratiform Au-Cu breccia zone in marble.
Age of mineralization Younger than the Late Proterozoic or Cambrian host rock.
Alteration of deposit If this deposit is similar to those in the Kael-7 Mile Trend (CR188), it is associated with silicification and dolomitization of the marble host rock.

Production and reserves

Workings or exploration Workings consists of a short adit and several open cuts over a distance of at least 0.5 mile.
Indication of production None

References

MRDS Number A010026

References

Hedderly-Smith, D.A., 1992, Report of 1992 work in the Kael-Dolomi area-Sealaska minerals project: Sealaska Corporation, 60 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1993, Report of the 1992 field season-Sealaska minerals reconnaissance project: Sealaska Corporation, 60 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1993, Report of the 1992 work in the Brennan Bay-Kitkun Bay area-Sealaska minerals reconnaissance project: Sealaska Corporation, 24 p. (Unpublished report held by the Sealaska Corporation, Juneau, Alaska.)
Hedderly-Smith, D.A., 1999, Inventory of metallic mineral prospects, showings and anomalies on Sealaska lands, 1988 through 1998: Sealaska Corporation, Juneau, Alaska, 217 p. (internal report held by Sealaska Corporation, Juneau, Alaska).
Reporters D.J. Grybeck (Applied Geology)
Last report date 5/1/2004