The Black Gossan occurrence is located on a north-northwest–trending ridge, approximately 5.8 kilometres north of Black Lake.
The area lies within the Omineca-Cassiar Mountains at the southern end of the Toodoggone gold camp. It occurs within a Mesozoic volcanic arc assemblage that lies along the eastern margin of the Intermontane Belt, a northwest-trending belt of Paleozoic to Neogene sediments, volcanics and intrusions bounded to the east by the Omineca Belt and to the west and southwest by the Sustut and Bowser basins.
Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Takla Group andesite flows and pyroclastic rocks. Takla volcanics have been intruded by Lower Jurassic granodiorite to quartz monzonite of the Black Lake Suite and are in turn unconformably overlain by or faulted against Lower Jurassic calc-alkaline volcanics of the Toodoggone Formation (Hazelton Group).
The dominant structures in the area are steeply dipping faults that define a prominent regional northwest structural fabric trending 140 to 170 degrees. In turn, high-angle northeast-striking faults (approximately 060 degrees) appear to truncate and displace northwest-striking faults. Collectively these faults form a boundary for variably rotated and tilted blocks underlain by monoclinal strata.
Locally, strong propyltic alteration is pervasive, with argillic alteration assemblages on fault surfaces. Strong oxidized pyritic and gossanous alteration forms a prominent supergene cap over the target.
Work History
The area has been explored in conjunction with the nearby Baker (MINFILE 094E 026) occurrence since the late 1960s and a complete exploration history can be found there.
In 1997, drilling on the North Black Gossan zone yielded 0.59 gram per tonne gold over 19.8 metres, including 1.54 grams per tonne gold over 6.42 metres in hole 97-9 (Assessment Report 25619).
In 2002, at the Black Gossan, 9 Diamond Drill holes were drilled by Sable Resources Ltd, two trenches were excavated and a soil grid was expanded. Drilling yielded only low values with one of the best being 0.14 gram per tonne gold and 2.2 grams per tonne silver and 88 parts per million copper (Assessment Report 27127). This 1.83 metre drill interval contained pyritic veins with up to 8 per cent pyrite.
In 2004, Sable Resources drilled three holes into the Black Gossan Zone. This was to be a progressive program that explored deeper into the zone. The deepest hole that was to go 600metres was stopped at 166.76 metres due to squeezing ground. The drilling did demonstrate that a copper-gold system exists and is increasing in grade with depth. Drilling intercepts on the Black Gossan area yielded broad anomalous copper-gold mineralization including 0.0095, 0.0037 and 0.0192 per cent copper with 0.08, 0.09 and 0.13 gram per tonne gold over 291.77, 185.06 and 166.76 metres in holes 04-26, -27 and -28, respectively (Assessment Report 27653).
In 2006, at the Black Gossan, Sable Resources drilled two NQ sized diamond drill holes, totaling 170.7 metres. These were abandoned at the porphyry target due to poor ground conditions. The holes intersected propylitically altered Takla Group volcanics over their entire length. Pyrite accounted for 1 to 2 per cent and was the only sulphide noted. No assays were completed.
In 2012, a program of prospecting, geological mapping and rock sampling was completed on the Baker claim group. Twelve rock samples from the Black Gossan area yielded values of up to 0.40 gram per tonne gold and 10.1 grams per tonne silver (Assessment Report 34394).
In 2015 and 2016, programs of prospecting, geological mapping and rock sampling were completed on the area. In 2017, drill hole BK17-04 yielded 0.12 gram per tonne gold, 0.017 per cent copper and 0.003 per cent molybdenum over 43.4 metres (Smith, A. (2019-04-04): Technical Report on the Baker Gold Project).
In 2020, TDG Gold Corp. completed a 11.9 line-kilometre ground induced polarization survey on the area northwest of Oxide Peak and an airborne geophysical survey on the area as part of the Baker-Shasta-Oxide Peak property.
