The Lake Fault occurrence is located at an elevation of 1700 metres, approximately 700 metres northeast of Mount Graves.

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 the early Jurassic granodiorite to quartz monzonite 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 area is underlain by volcanics and volcaniclastics of the Jurassic Hazelton Group. These rocks form the eastern limb of a north-northwest–trending faulted anticline. Regionally, these rocks have been subdivided into four informal units (Forster, 1984), which at the Mount Graves prospect, dip 50 to 80 degrees to the northeast. Welded and partially welded andesite pumice breccia, overlain by grey, green to orange hornblende porphyritic andesitic flows and pyroxene andesite flows; lesser thin discontinuous lenses of greywacke and laminated siltstone comprise lithologies of the Hazelton Group. Quartz monzonite dikes are found in the faulted core of the regional anticline and along northeast and east-striking faults. A series of quartz feldspar porphyry rhyolitic dikes, striking northwest and dipping steeply, occur subparallel to bedding.

Locally, steeply dipping, east-northeast–striking faults host thin, less than 4-centimetre wide, quartz veins. Immediately to the south galena and sphalerite have been identified in float samples.

In 1981, a rock sample (I-C-9130) assayed 1.23 grams per tonne gold and 37 grams per tonne silver (Assessment Report 10050).

In 1987, rock samples from the area yielded up to 0.06 gram per tonne gold and 5.7 grams per tonne silver (Assessment Report 17326).

In 1996, a sample of quartz float from the area yielded 0.26 gram per tonne gold and 40.9 grams per tonne silver (Assessment Report 24993).

Work History

The area has been explored in conjunction with the nearby GWP (MINFILE 094E 087) occurrence and a completed exploration history can be found there.