The Lon occurrence is located east of the Horseranch Range, in the valley of the Red River, about 142 kilometres northeast of the community of Dease Lake.

The occurrence is hosted within the Kechika Trough. The Kechika Trough and its northern extension, the Selwyn Basin, are elongate, rift-controlled, sedimentary basins that formed along the North American continental margin during the Upper Proterozoic to Paleozoic. The Lon property lies approximately 23 kilometres west of the mapped trace of the Northern Rocky Mountain Trench fault, a major dextral strike-slip component of the Tintina fault zone.

The region surrounding the Lon showing is underlain by the regionally extensive, Upper Cambrian to Middle Ordovician Kechika Group, which consists broadly of generally well-bedded, moderately to strongly deformed, and weakly to non-metamorphosed limestones and variably carbonaceous argillites, siltstones, shales, slates, and conglomerates. Both mineralization anomalies (see below) are underlain by the Lower Silurian Sandpile Group, which is locally characterized by tan weathering, sandy dolomites or dark-grey dolomites with sandy beds (Assessment Report 6841).

Quartz-carbonate veins with barite, sphalerite, galena and pyrite cut tan and dark-grey dolomites of the Ordovician-Lower Devonian Sandpile Group. Larger veins strike northeast, whereas smaller veins are discontinuous and irregular.

In 1978, Amoco Canada Petroleum Co. Ltd. completed a soil geochemistry program (894 samples) over the Lon claims. Two anomalous zones were identified. The East Zone is characterized by a lead-zinc-barium anomaly (3450 parts per million lead, 6200 parts per million zinc and 9 per cent barium); plots of a 300-parts-per-million contour for lead define a 400-metre long anomaly with a north-west trend. This anomaly corresponds with an area of tan-weathered dolomite outcrop cut by numerous barite veins (Assessment Report 6841). The West Zone is also characterized by elevated lead, zinc and barium, most notably zinc. Plots of a 500-parts-per-million contour for zinc define an 1800-metre long anomaly with a west-northwest trend, which parallels a ridge of grey-weathering dolomites that contain numerous barite-galena-pyrite-sphalerite veins.