The Gifford’s Edge occurrence is located on a north-northeast–trending ridge, south of the Toodoggone River and approximately 1.1 kilometres north-northeast of Marmot Lake.
The area lies within the Omineca-Cassiar Mountains at the southern end of the Toodoggone gold camp. The area is situated 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.
The occurrence area is underlain by andesite crystal tuffs, volcaniclastic breccias and hypabyssal quartz trachyandesites, part of a larger package of Toodoggone Formation volcanics assigned to the Metsantan member and dacitic volcanic rocks of the Saunders member. Other lithologies of the Metsantan member include mostly latite lava flows with interflow lahar, and a mix of epiclastic and pyroclastic rocks (Bulletin 86).
Locally, a pervasively propylitic-altered volcanic hosts disseminated pyrite and potassic-altered northwest-southeast–trending structures with silica and pyrite veining.
Work History
The area has been explored in conjunction with the nearby Lawyers (MINFILE 094E 066) occurrence and a complete regional exploration history can be found there.
In 2018, Benchmark Metals Inc. and PPM completed a program of geochemical (rock and soil) and biogeochemical sampling, a 1272 line-kilometre airborne radiometric survey, eight diamond drill holes, totalling 1493.0 metres, and 30 rotary drill holes, totalling 2623.0 metres. This work focused along the Layers mineralization trend, which is greater than 3 kilometres in length. Two rock samples (Y445284 and Y445287) from the west side of the ridge yielded 0.163 and 0.132 gram per tonne gold with up to 12.65 grams per tonne silver (Assessment Report 38447). No descriptions were provided for the two samples.
In 2019 and 2020, Benchmark Metals Inc. completed programs of geochemical (rock and soil) and biogeochemical sampling, ground and airborne geophysical surveys, 242 diamond drill holes, totalling 69 080 metres, and 191 reverse circulation drill holes, totalling 28 395 metres, on the area as part of the Lawyers property. The majority of the drilling targeted the Cliff Creek, Dukes Ridge, Phoenix and AGB zones of the Lawyers (MINFILE 094E 066) deposit. Grab samples from the Gifford’s Edge zone are reported to have yielded up to 27.9 grams per tonne gold and 378 grams per tonne silver (P&E Mining Consultants Inc. [2021-06-28]: Technical Report and Updated Mineral Resource Estimate of the Lawyers Gold-Silver Property, Omineca Mining Division, British Columbia, Canada). Additional work was completed on the Lawyers property by Benchmark Metals Inc. in 2021 (see Assessment Reports 39149 and 39489.
