Lucky Saddle

Prospect, Active

Commodities and mineralogy

Main commodities Ag; Au; Cu; Fe; Hg; Pb; Sb; Zn
Ore minerals arsenopyrite; chalcopyrite; galena; gold; pyrite; pyrrhotite; sphalerite; stibnite
Gangue minerals ankerite; quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale A-1
Latitude 63.1827
Longitude -147.2476
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Lucky Saddle prospect is about 0.3 mile south of the top of Lucky Hill between Roosevelt Creek and White Creek. It is about 0.2 mile north-north west of the center of section 18, T. 20 S., R. 3 E. The location is accurate.

Geologic setting

Geologic description

The Lucky Saddle prospect is one of four deposits that was explored by CanAlaska Resources Ltd. from 1983 to at least 1996 as the Rainbow Hill project. It and the nearby Gold Hill (HE209), Lucky Top (HE210), and TMC (HE211) prospects share a similar origin and general characteristics. The Rainbow Hill project is described in considerable detail by Adams (1996) and Freeman (2002); most of what follows is based on their work.
The rocks in the area consist of Jurassic to Cretaceous, argillite, graywacke, siltstone, and mafic tuff intruded by small stocks and dikes of Tertiary and Cretaceous gabbro and diorite (Smith, 1981). The rocks were subject to lower-greenschist-grade to amphibolite-grade metamorphism in the Cretaceous and early Tertiary. Airborne geophysical data suggest that the Gold Hill/Lucky Top area that roughly coincides with the Rainbow project is underlain by a shallow, structurally deformed, metamorphosed igneous complex. The regional structure is dominated by a set of east-west trending thrust faults and by cross-cutting high-angle faults. A set of northwest trending, high-angle faults and dikes associated with the mineralization is offset by northwest- and northeast-trending faults.
The mineralization in the Rainbow Hill area consists of zones of stacked sulfide-bearing, ankerite-quartz veins and stockworks that strike east and dip variably to the north and south. The sulfides in the veins and stockworks are mainly pyrite and arsenopyrite; minor amounts of pyrrhotite, chalcopyrite, galena, stibnite, and sphalerite occur widely, as does visible gold. Abundant sulfides usually indicate high gold values. The auriferous zones typically have a central area of intense silicification, sericitization, and carbonatization that weakens outward. Sericite from the veins has been dated at 57.6 to 63.1 Ma by argon-argon methods.
Although there had been some earlier work on the gold veins in the Gold Hill/Lucky Top area (Moffit, 1912; Ross, 1933; Tuck, 1938), the first intensive exploration in the area began in 1983 when CanAlaska began a program of surface mapping, outcrop sampling, soil geochemical surveys, trenching, and ground geophysical surveys. The work resulted in the discovery of the Lucky Saddle prospect on a northeast-trending soil anomaly in gold, about 3,400 feet long and 800 feet wide. Trenches dug across the prospect in 1989 exposed metamorphosed hornfels and diorite dikes cut by a shear zone about 200 feet wide. Chip samples in the trenches contained 0.415 ounce of gold per ton across 5 feet and 0.05 ounce of gold per ton across 20 feet. The samples were also highly anomalous in arsenic, lead, and zinc, and contained some antimony, silver, and mercury.
Geologic map unit (-147.249858680901, 63.182253596033)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization About 60 Ma based on the age of sericite from the quartz veins.
Alteration of deposit The mineralization is associate with pervasive sericite-carbonate-quartz alteration; local hornfelsing and tourmalinization.

Production and reserves

Workings or exploration Although there had been some earlier work on the gold veins in the Gold Hill/Lucky Top area ( Moffit, 1912; Ross, 1933; Tuck, 1938), the first extensive exploration in the area started in 1983 with a program of surface mapping, outcrop sampling, soil geochemical surveys, trenching, and ground geophysical surveys by CanAlaska. The work resulted in the discovery of the Lucky Saddle prospect on a northeast-trending soil anomaly in gold. Several trenches were dug on the mineralization in 1989.
Indication of production None

References

References

Reporters D.J. Grybeck (Port Ludlow, WA)
Last report date 6/5/2008