The Punch Bowl occurrence is located in the northern headwaters of Pacific Creek, a tributary of the Wood River. This lies at the boundary between the eastern and the western Main Ranges of the Continental Ranges at Athabasca Pass, approximately 60 kilometres south-southwest of Jasper. This boundary is coincident with the continental divide.
Regionally, the area is marked by the southwest-dipping Chatter Creek thrust fault. To the southwest the hangingwall of the Chatter Creek thrust is composed of grits, pelites, psammites and carbonates of the Hadrynian Miette Group and overlying Lower Cambrian clastics of the Gog Group. The region is dominated by broad open folds that make up the Baker Glacier syncline and Porcupine Creek anticlinorium. To the northwest the Chatter Creek thrust sheet contains the Fraser River antiform. Within the Chatter Creek thrust sheet, metamorphic grade increases westward from greenschist to kyanite-staurolite–bearing assemblages of amphibolite grade.
The footwall of the Chatter Creek thrust sheet to the north and east is composed of the Lower Cambrian Gog Group, overlain by a series of thickly bedded, Middle Cambrian, dominantly carbonate rocks striking 325 degrees and dipping 20 degrees. Tight to isoclinal, overturned mesoscopic folds occurring within imbricate quartzite slices, within this thrust sheet, have fold axes that trend 140 to 150 degrees and plunge gently southeast.
Within the occurrence area, the Gog Group strata are subdivided into the lowermost McNaughton, the Mural and uppermost Mahto formations, in the immediate footwall of the Chatter Creek thrust. Gold-mineralized quartz veins are contained solely within the McNaughton Formation. The predominant lithology is a medium- to coarse-grained, moderately to poorly sorted, pale-weathering, gray feldspathic quartzite. Other lesser lithologies include pelite and conglomerate.
Paleo-environmental interpretations of the McNaughton Formation include a tidally dominated association of a shallow marine shelf environment in the Eastern Main Ranges to tidal complex transitions in more westerly outcrops.
Locally, gold-quartz mineralization is contained in a series of discrete vein structures confined to quartzites and lesser pelites of the McNaughton Formation. More than 20 veins have produced anomalous gold values; although distribution of gold within individual veins is highly erratic. Visible gold has been observed. Thus far only bedding-parallel veins contain high-grade gold mineralization. These veins vary from a few centimetres thick by 1 metre long up to 70 to 100 centimetres wide by 50 metres long. Observations show all bedding-parallel veins intrude pelite and/or quartzite, with breccia textures common within veins. Vein size and distribution is fundamentally controlled by the geometry and distribution of the original pelitic layers, particularly where pelitic horizons contain greater than 30 per cent detrital quartz.
Quartz is the dominant vein-filling phase, comprising greater than 95 per cent of the total vein volume. Variable and unevenly distributed pyrite, native gold, galena, sphalerite, carbonate and white mica, and potassium feldspar make up the remaining modal fraction. The distribution of hydrothermal vein constituents is markedly higher in zones of intense pelite brecciation. The majority of quartz was deposited as open space filling during multiple phases of vein opening. Two broad generations of vein filling have been recognized in the building of bedding parallel veins. The second stage of vein filling represents a late incursion of hydrothermal fluids during which most of the gold was deposited. Wallrock alteration is noticeably absent adjacent to most bedding-parallel veins but wallrock sulphidization likely accompanied gold stage vein filling.
With respect to regional deformation, gold mineralization appears to be late stage; hence, structures and veining associated with incipient phase three deformation may prove significant. Gold emplacement and discordant veining were confined to the onset of late compressional deformation leading to the development of the Chatter Creek thrust.
In 1987, a rock sample (PB-27) of mineralized quartz vein material from the main showing area yielded 180.8 grams per tonne gold (Assessment Report 16242).
In 1989, three samples (38522 through 38524) taken from approximately the 2090 metre level of McGillivray Ridge from a well-mineralized, bedding-parallel vein yielded values from 26.29 to 573.7 grams per tonne gold (Assessment Report 19354).
In 2020, 2021 and 2023, rock samples (148681, 151879 and 150878) of quartz vein material from an area of outcrop exposing a 15-metre long and up to 1-metre wide quartz vein with brecciated pelitic fragments located near the British Columbia–Alberta border yielded 3.41, 1.97 and 4.70 grams per tonne gold, respectively (Assessment Reports 39433, 40484 and 41530).
Work History
In the 1920s, minor placer gold workings are reported to have occurred on the Wood Arm to the south and on Hugh Allan Creek to the northeast. In the late 1960s, gold-bearing talus was discovered in the area by Mr. Klettl Sr.
In 1987, Gamsan Resources Ltd. conducted a program of prospecting, geological mapping and geochemical (rock and silt) sampling on the area as the Punch 1-7 and Bowl 1-2 claims of the Punch Bowl property. In 1988 and 1989, a further program of prospecting, geological mapping, rock sampling and petrographic analysis was conducted. In 1991, a further program of prospecting was conducted.
During 2020 through 2023, Pegasus Resources Inc. completed programs of prospecting, geological mapping and rock sampling on the area as the Punch Bowl property.
