The Keen Creek limestone prospect is situated on Keen Creek, 8 kilometres west of Kaslo, in the Slocan Mining Division.
Regionally, the area lies on the western margin of the Kootenay Arc, in allochthonous rocks of the Quesnel Terrane. In the vicinity of the occurrence, the Quesnel Terrane is dominated by the Upper Triassic Slocan Group, a thick sequence of deformed and metamorphosed shale, argillite, siltstone, quartzite and minor limestone. Rocks of the Slocan Group are tightly and disharmonically folded. Early minor folds are tight to isoclinal with moderate east plunging, southeast inclined axial planes and younger folds are open, southwest plunging with subhorizontal axial planes. The sedimentary sequence has been regionally metamorphosed to lower greenschist facies.
South and west of the occurrence, the Slocan Group has been intruded by the Middle Jurassic Nelson intrusions which comprise at least six texturally and compositionally distinct phases ranging from diorite to lamprophyre. The most dominant phase is a medium to coarse grained potassium feldspar porphyritic granite. Several feldspar porphyritic granodiorite dikes, apparently related to the Nelson intrusions, also cut the sedimentary sequence near the occurrence (Paper 1989-5).
The main outcrop is exposed for 140 metres in a westerly direction along the mountainside next to the creek. A series of partings that may represent bedding strike 100 degrees and dip 35 degrees northeast. A closely spaced joint set strikes 030 degrees and dips nearly vertical. The limestone is fine grained and uniform white to white with blue blotches and bands. A sample assayed 53.40 per cent CaO, 1.46 per cent MgO, 0.64 per cent insolubles, 0.15 per cent Al2O3, 0.15 per cent Fe2O3, 0.07 per cent P2O5, 0.25 per cent SO3 and 43.00 per cent ignition loss (Geological Survey of Canada Memoir 173, page 54, Sample 1).
A smaller exposure further down the creek to the east displayed bluish mottled to light bluish white, fine grained limestone striking 110 degrees and dipping 40 degrees northeast.
The limestone was staked for marble by F. Archer and E. Timms sometime before 1917.
