Weeno

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Ag; Cu; Pb; Zn
Ore minerals chalcopyrite; galena; pyrite; pyrrhotite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale C-1
Latitude 64.5641
Longitude -141.0972
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Weeno prospect is located in the headwaters of Weeno and Karen Creeks, which are not labeled on the U.S. Geological Survey topographic map of the Eagle C-1 quadrangle (1956). The prospect is centered just east of hill 4048 in the southeast part of the Eagle C-1 quadrangle. The coordinates are the approximate center of the Weeno prospect area in section 15, T. 4 S., R. 33 E of the Fairbanks Meridian. The location is accurate only within 2 miles. The Weeno prospect is located within Doyon, Ltd. selected or conveyed land.

Geologic setting

Geologic description

The rocks in the vicinity of the Weeno prospect are chert, weakly metamorphosed siltstone and carbonaceous shale, argillite, and graywacke, limestone, chlorite-quartz-muscovite-talc schist, and graphitic schist (WGM Inc., 1998 [DLR 98-12]). These rocks have been correlated with the Nasina assemblage of Devonian and (or) Mississippian age (Dusel-Bacon and others, 1998). At the Weeno prospect, a sulfide-bearing chert horizon that is at least 200 feet thick appears to dip moderately to the west-northwest and grades stratigraphically downward into interlayered siltstone and carbonaceous shale. The banded texture of the sulfides, the chert host rock, and the association with a contact between metavolcanic schist and graphitic schist suggest that the sulfides are of volcanogenic or sedimentary exhalative origin. The weakly metamorphosed carbonaceous siltstone and shale near the creek bottom and on east-facing slopes resemble rocks at the Lead Creek prospect nearby to the southwest (EA057).
Galena was first observed in the southeast Weeno prospect area by Foster and Clark (1969). Anomalous copper, lead, zinc, and silver were found in stream sediments near the headwaters of Weeno Creek and in tributaries to Karen Creek, located about one-half mile to the south (WGM Inc., 1998 [DLR 98-12]. An assay of an iron-rich seep draining chlorite-quartz-muscovite-talc schist assayed 16 ppm silver, 133 ppm copper, 2,520 ppm lead, and 1,340 ppm zinc. Two bedded chert outcrops 1.5 miles apart that contain pyrite and pyrrhotite, and trace galena, sphalerite, and chalcopyrite contain as much as 6,358 ppm zinc and 1,500 ppm copper.
Lead, zinc, copper and silver anomalies in soils collected on a grid at the Weeno prospect trend northeast for 4,000 feet and are as much as 800 feet wide (WGM Inc., 1998 [DLR 98-12]). Silicified siltstone underlies the south part of the soil grid. Elsewhere, chlorite-quartz-muscovite-talc schist is thrust over chert. The lead anomaly on the upper plate of the thrust is wide but weak and trends southwest. On the lower plate, the lead anomaly is narrow and has two strong, 4,500-foot-long, northeast trends with as much as 1,825 ppm lead. The zinc anomaly (greater than 100 ppm zinc) is very broad on the upper plate and is open to the north and south. Zinc is elevated along the trace of the thrust fault, indicating possible remobilization of metals. The lower-plate zinc anomaly (as much as 2,390 ppm zinc) coincides with the lead anomaly and is open to the north and south. The copper anomaly (as much as 444 ppm) is uphill from the lead and zinc anomalies. It is broad, irregular, and weak on the upper plate but narrower and stronger on the lower plate. The silver anomaly is coincident with the other base metals and is open to the north and south (WGM Inc., 1998 [DLR 98-12]).
Airborne geophysical data indicate a zone of high resistivity over silicified rocks at the Weeno prospect, but the zone of highest resistivity is located approximately 3,000 feet west of the soil anomaly (WGM Inc., 1998 [DLR 98-12]). An area of high magnetic susceptibility is located south of the silicified zone, suggesting ultramafic rocks may underlie the siltstones.
WGM Inc. conducted reconnaissance stream-sediment sampling in the Weeno prospect area in 1976 (Dashevsky and others, 1986). Exploration of the Weeno prospect by WGM Inc. in the mid-1990s included stream-sediment sampling, geologic mapping, and soil and rock sampling (WGM Inc., 1998 [DLR 98-12]). In 1996, WGM Inc. conducted soil sampling on a 5,000 foot by 6,000 foot grid.
Geologic map unit (-141.099490753669, 64.5638195893935)
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a).
Mineral deposit model number 28a
Age of mineralization Host rocks of sulfides at the Weeno prospect have been correlated with the Nasina assemblage of Devonian and (or) Mississippian age (Dusel-Bacon and others, 1998); hence, if the sulfides are stratiform, they may also be Devonian-Mississppian.
Alteration of deposit Siltstone at the Weeno prospect has been silicified (WGM Inc., 1998 [DLR 98-12]).

Production and reserves

Workings or exploration WGM Inc. conducted reconnaissance stream-sediment sampling in the Weeno prospect area in 1976 (Dashevsky and others, 1986). Exploration of the Weeno prospect by WGM Inc. in the mid-1990s included stream-sediment sampling, geologic mapping, and soil and rock sampling (WGM Inc., 1998 [DLR 98-12]). In 1996, WGM Inc. conducted soil sampling on a 5,000 foot by 6,000 foot grid.
Indication of production None

Additional comments

The Weeno prospect is located within Doyon, Ltd. selected or conveyed land. For more information contact Doyon, Ltd., Fairbanks, Alaska.

References

References

Dashevsky, S.S., Nicol, D.L., and Bond, J., 1986, Mines, prospects, and geochemical anomalies on Doyon Limited regional overselection lands, Alaska, Blocks 1-8: Doyon, Ltd. Report 86-01a, 300 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).
WGM Inc., 1977, Doyon Project, 1976 annual progress report, volume 1a, Blocks 1, 4, 5, 7, 8: Doyon, Ltd. Report 77-02a. (Report held by Doyon, Ltd., Fairbanks, Alaska).
WGM Inc., 1998, Ventures Resource Alaska projects, 1997 progress report, Champion property exploration: Doyon, Ltd. Report 98-12, 64 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Reporters M.B. Werdon; R.L. Flynn
Last report date 5/1/2002