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File Created: 21-Jan-1988 by Mary McLean (MM)
Last Edit:  05-Jun-2020 by George Owsiacki (GO)

Summary Help Help

NMI
Name JED Mining Division Liard
BCGS Map 104I035
Status Showing NTS Map 104I06E
Latitude 058º 23' 42'' UTM 09 (NAD 83)
Longitude 128º 59' 54'' Northing 6472688
Easting 500097
Commodities Gold, Talc, Copper Deposit Types M02 : Tholeiitic intrusion-hosted Ni-Cu
M07 : Ultramafic-hosted talc-magnesite
I05 : Polymetallic veins Ag-Pb-Zn+/-Au
Tectonic Belt Intermontane Terrane Cache Creek, Plutonic Rocks
Capsule Geology

The Jed occurrence is in the valley of Wheaton Creek, just south of the Turnagain River, about 60 kilometres east of the community of Dease Lake. Access is by a bulldozer road which leads off the Cassiar-Stewart road in the Tanzilla River valley. Substantial quantities of gold are reported to have been recovered from placer mining on Wheaton Creek (104I 004).

The area is underlain by a 5 kilometre wide belt of upper Mississippian to Permian ultramafic rocks of the Cache Creek Complex consisting of peridotite, dunite and pyroxenite. Small areas consisting of sediments (chert, slate, argillite, graphitic schist, and limestone) occur and are probably part of the Mississippian to Triassic Kedahda Formation (Cache Creek Complex). These are believed to be in fault contact with the ultramafics. North of the Turnagain River, Lower Jurassic (Toarcian) granodiorite intrudes the ultramafics.

The ultramafics are completely altered to dark green to black serpentinite with small grains of magnetite and minor partially altered pyroxene. Apparently "considerable amounts" of talc occur with these rocks.

Drilling in 1984 on the Jed claim (for sulphides in quartz veins), revealed numerous talc zones. Drillhole 2 cut graphitic schist with narrow serpentine and talc zones from 53 to 87 metres. In drillhole 3, talc schist occurs from 5 to 38 metres, which is locally silicified and brecciated and has small concentrations and disseminations of amorphous mariposite. From 38 to 46 metres, narrow talc zones occur in graphitic schists. Drillhole 4 intersected 19 metres of talc schist with zones of serpentine from 39 to 57 metres (Assessment Report 13627). Pyrite occurs in veinlets and fracture fillings while pyrrhotite and chalcopyrite are more disseminated within graphitic schist in drillholes 2, 3 and 4.

In 1986, drilling was done to explore the downdip extension of surface exposures of quartz zones with gold values. A quartz-calcite breccia zone was intersected in drillhole 86-1 at between 14.6 to 32.3 metres. The rock is described as a graphitic schist, locally intensely silicified and containing pyrite, pyrrhotite and chalcopyrite. The interval from 29 to 32 metres assayed 5.38 grams per tonne gold (Assessment Report 16332). However, samples below and above (both 3 metre samples) yielded only traces of gold.

Bibliography
EMPR ASS RPT *13627, *16332
EMPR EXPL 1985-C388; 1987-C384
EMPR OF 1988-19, pp. 48-49; 1989-18; 1996-11
GSC OF 610; 2262; 2779
GSC BULL 504
GSC MAP 9-1957; 29-1962; 1418A; 1712A
GSC P 78-1A, pp. 25-27

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