Although no significant bedrock mineralization is apparent, this occurrence has been created to represent a wide area, straddling lower Bluff Creek, of gossaneous outcrops and anomalous multi-element rock, soil and silt geochemical results. The geochemical signature was considered by explorationists to be indicative of both lead-zinc and nickel-zinc massive sulphide (SEDEX) potential (Assessment Reports 21160, 21980).
The occurrence is centred on a gossan on the north side of the creek, roughly in the middle of the anomalous area (Open File 1995-4; Assessment Report 21980, Figure 3). It is 6.5 kilometres northeast of the Gataga River and 7.5 kilometres east-southeast of Brownie Mountain in the Muskwa Ranges of the Northern Rocky Mountains.
The area lies at the northwestern extremity of the Gataga mineral district, in a belt of Paleozoic basinal-facies sedimentary strata known as the Kechika Trough, part of Ancestral North America (Map 38; Exploration and Mining Geology, Volume 1; Geological Survey of Canada Map 1713A). The Gataga mineral deposits are characterized by stratiform sedimentary-exhalative barite-sulphide mineralization, particularly in the Middle to Upper Devonian Gunsteel Formation (informal name) of the Devono-Mississippian Earn Group.
This region, which is just northeast of the Northern Rocky Mountain Trench, is underlain by Cambrian to Devono-Mississippian sedimentary rock units that have been deformed into tight, northeast-overturned folds and imbricated by thrust faults (Fieldwork 1994, Open File 1995-4; Geological Survey of Canada Map 1712A, Paper 88-1E). The general strike is northwest, and the dominant dip is moderately to steeply southwest. The oldest rocks in the immediate area are siliciclastics and limestone of an unnamed Middle to Upper Cambrian unit. Stratigraphically above these are slate and limestone of the Cambro-Ordovician Kechika Group; calcareous and non-calcareous siltstone and slate, and carbonate of the Ordovician to Lower Devonian Road River Group; and finally carbonaceous and siliceous slate and siltstone of the Earn Group.
The lower Bluff Creek valley cuts westwards through all these stratigraphic units; in fact, they are partly repeated in at least six thrust panels. Of interest is the Earn Group, probably mostly Gunsteel Formation, which outcrops in at least two narrow, mainly thrust-bounded belts over a width of 2 kilometres, halfway between the Netson Creek valley and the Gataga River. This belt is not well exposed but is marked by a number of ferricrete outcrops, gossans and locally calcrete or tufa deposits (some of them may actually rest on pre-Earn, Road River Group rocks). These deposits tend to have much more elevated values of zinc and nickel than lead or copper, reflecting the greater solubilities of those elements. High zinc values are also reported for some slate or shale samples in the vicinity, but without more detailed descriptions it cannot be assumed that they were not contaminated by the metal-enriched groundwaters (Assessment Report 7291). Outcrops of unaltered slate or siltstone are not mineralized except for disseminated pyrite, although bedded barite or small nodules of barite have been found in the Earn Group in a few places (Assessment Report 9468).
Work History
In 1978, Texasgulf Canada Ltd. completed a program of geological mapping and geochemical (rock, soil and silt) sampling on the area as the Red Bluff claims. Sampling of small spring iron gossans hosted in shale yielded up to 0.39 per cent zinc (Sample 921B/2/78) in the vicinity of the Spring iron Pit 78-A, whereas samples of white calcrete deposits yielded up to 4.00 per cent zinc (Sample 921B/6A/78; Assessment report 7291).
In 1981 and 1982, Noranda Mining and Exploration Inc. completed soil sampling programs on the surrounding area as the Heavy, Split, Top, Weight, New and Moon claims.
In 1990 and 1991, NDU Resources Ltd. completed a program of prospecting, geological mapping and geochemical (rock, silt and soil) sampling on the area as the Netson property. Rock samples from gossanous zones yielded up to greater than 1.00 per cent zinc, 0.41 per cent nickel and 26.2 grams per tonne silver (Assessment Report 21160).
A sample of ferricrete assayed 5.19 per cent zinc, 0.336 per cent nickel, 0.364 per cent magnesium, 5.23 per cent iron and 0.032 per cent cadmium (Geoscience Map 1998-9).
In 2011 and 2012, BCarlin Resources Ltd. completed regionally extensive programs of geochemical (rock, silt and soil) sampling on the area as the Netson Lake property. A float boulder sample (P421069) of possibly reworked calcrete from the occurrence area assayed 0.82 per cent zinc, whereas a rock sample (P421080) from a gossanous layer, located southeast of the previous sample, yielded 0.26 per cent zinc (Assessment Report 33582).
