Little Jarvis

Prospect, Active

Alternative names

RW

Commodities and mineralogy

Main commodities Ag; Cu; Zn
Other commodities Au
Ore minerals barite; chalcopyrite; pyrite; sphalerite
Gangue minerals chlorite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale B-4
Latitude 59.4001
Longitude -136.4133
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Little Jarvis prospect is probably the prospect that Rubicon Minerals drilled in 1999 as the RW. It is of the east side of the Little Jarvis Glacier about 0.7 mile northwest of peak 1745 (meters) which is locally called Mt. Moorian. It is about 0.2 mile southwest of the center of section 33, T. 28 S., R. 55 E.

Geologic setting

Geologic description

Mineralization in this area was discovered in 1969 by Merrill Palmer and associates and has been explored by a succession of companies including Alyu Mining in 1976 and 1977; Anaconda Minerals in 1979 and 1980; Southeastern Minerals from 1980 to 1983; Bear Creek Mining from 1983 to 1985; Newmont Exploration from 1987 to 1989; Granges Exploration Ltd. in 1989; Cominco Alaska from 1990 to 1993; Kennecott Minerals from 1993 to 1997, Rubicon Minerals from 1998 to 2000; and Toquima Minerals Corp. in 2004. It was also mapped and sampled by the U.S. Geological Survey (MacKevett 1974) and the U.S. Bureau of Mines (Still, 1984), and the Alaska Division of Geological and Geophysical Surveys (Still and others, 1991). In 2006, Constantine Metal Resources acquired the property under a long-term lease and they have been actively explored it to the present (early 2011). Their work has included detailed geologic mapping and sampling, ground geochemical and geophysical surveys, and through 2009 they had drilled 32 holes just a mile to the east on the Glacier Creek prospect (SK066). The Jarvis Creek prospect was probably found early in the history of the work in the area. Kennecott Minerals drilled one hole in 1994 and Rubicon Minerals Ltd. drilled 6 holes in 1999 under the name RW. It is now part of the large block of claims held by Constantine who call it the Little Jarvis prospect.
The rocks in the region are part of the Upper Triassic Hyd Group that hosts similar volcanic massive sulfide deposits the length of southeastern Alaska (Newberry and others, 1997). The rocks are predominantly massive and pillow basalts and fragmental basalt and andesite(?), intercalated with siltston, tuff, and rare rhyolite flows and dikes. They have been subject to greenschist-facies metamorphism; folding and faulting locally repeats the stratigraphy in places, and the rocks are highly altered.
The drilling by Rubicon Minerals in 1999 (Rubicon Minerals (1998) discovered massive sulfide mineralization. Mineralization intersected in drill holes occurs as: 1) chalcopyrite-sphalerite massive-sulfide mineralization, and 2) chalcopyrite-bearing, stringer in a zone of strong chloritic alteration. The massive-sulfide, drill-intersect thicknesses ranged from 7.2 feet to 15 feet and contained up to 13.48 percent zinc, 1.89 percent copper, 2.98 ounces of silver per ton, and 0.02 ounces of gold per ton. Massive-sulfide drill intercepts extend along a dip length of 420 feet. The stringer mineralization is beneath the massive sulfide horizon. One drill hole intersected 156 feet of stringer mineralization that included a 67.8-foot-thick interval with an average grade of 0.62 percent copper. In this interval, there was a 16.2-foot interval that contained 1.50 percent copper. There has not been any drilling on the Little Jarvis prospect since 1999, but there has been extensive drilling and exploration on the nearby Glacier Creek prospect (SK066) where the RW zone is extensive. Although it is likely that the mineralization at this prospect is a continuation of the mineralization of the Glacier Peak prospect whose orientation is controlled by a large overturned east-west-trending antiform, recent mapping by Constantine (figure 8 of Greig and Giroux, 2010) suggests that the Little Jarvis mineralization trends north-northwest.
There have been several published studies of the mineral deposits in the area by government and academe (MacKevett and others, 1974; Still, 1984, Still and others, 1991; Newberry and others, 1997; Greig and Giroux, 2010) and unpublished studies by industry. The consensus from early on was that the they are Late Triassic, stratiform volcanogenic massive-sulfide deposits.
Geologic map unit (-136.415165452015, 59.3997631768611)
Mineral deposit model Kuroko- or Besshi-type volcanogenic massive-sulfide deposit (Cox and Singer, 1986; models 28a or 24b).
Mineral deposit model number 28a or 24b
Age of mineralization Late Triassic by analogy with other similar deposits of that age along the length of southeastern Alaska and into Canada.
Alteration of deposit Intense sericitic and chloritic alteration associated with the layers of massive sulfides.

Production and reserves

Workings or exploration Mineralization in this area was discovered in 1969 by Merrill Palmer and associates and has been explored by a succession of companies including Alyu Mining in 1976 and 1977; Anaconda Minerals in 1979 and 1980; Southeastern Minerals from 1980 to 1983; Bear Creek Mining from 1983 to 1985; Newmont Exploration from 1987 to 1989; Granges Exploration Ltd. in 1989; Cominco Alaska from 1990 to 1993; Kennecott Minerals from 1993 to 1997, Rubicon Minerals from 1998 to 2000; and Toquima Minerals Corp. in 2004. It was also mapped and sampled by the U.S. Geological Survey (MacKevett 1974) and the U.S. Bureau of Mines (Still, 1984), and the Alaska Division of Geological and Geophysical Surveys (Still and others, 1991). In 2006, Constantine Metal Resources acquired the property under a long-term lease and they have been actively explored it to the present (early 2011). Their work has included detailed geologic mapping and sampling, ground geochemical and geophysical surveys, and through 2009 they had drilled 32 holes just a mile to the east on the Glacier Creek prospect (SK066). The Jarvis Creek prospect was probably found early in the history of the work in the area. Kennecott Minerals drilled one hole in 1994 and Rubicon Minerals Ltd. drilled 6 holes in 1999 under the name RW. It is now part of the large block of claims held by Constantine who call it the Little Jarvis prospect. It has undoubtedly been mapped, sampled, and covered by geochemical and geophysical surveys by several of the companies that have worked in the area. It is now part of the large block of claims held by Constantine who call it the Little Jarvis prospect.
Indication of production None
Reserve estimates None.
Production notes None.

References

MRDS Number 10308256

References

Constantine Metal Resources Ltd., 2008, Palmer property info: http://www.constantinemetals.com/projects/palmer/palmer/ (as of April 9, 2008).
Greig, C.J., and Giroux, G.H., 2010, Palmer VMS project, southeast Alaska; Mineral resource estimation and exploration update: Technical l report for Constantine Metal Resources Ltd. 82 p. (posted on www.sedar.com, Mar. 8, 2010).
Newberry, R.J., Crafford, T.C., Newkirk, S.R., Young, L.E., Nelson, S.W., and Duke, N.A., 1997, Volcanogenic massive sulfide deposits of Alaska, in Goldfarb, R.J. and Miller, L. D., eds., Mineral deposits of Alaska: Economic Geology Monograph 9, p. 120-150.
Rubicon Minerals, 1998, Palmer VMS Project, southeast Alaska, Executive Summary: Unpublished report by Rubicon Minerals Corporation, Vancouver, British Columbia, 25 p.
Reporters T.C. Crafford (T. Crafford & Associates, Anchorage); D.J. Grybeck (Contractor, USGS)
Last report date 2/28/2011