The Buck Ridge deposit is located in the vicinity of the Buck Ridge post office on the west side of the Fraser River, 27 kilometres south of Quesnel.
In the Quesnel region Tertiary volcanic and sedimentary rocks overlie Paleozoic and Mesozoic rocks of the Cache Creek and Nicola Groups. These Tertiary rocks range in age from Paleocene to Pliocene but are dominated by plateau basalts of Miocene age and an underlying sedimentary succession including tuffs, conglomerate, sandstone and shale. Included in this sedimentary assemblage is a horizon of diatomaceous earth from which past production is recorded.
The area has been disrupted by faulting and the diatomite occurs as rather small disconnected blocks at various elevations. It is likely that the diatomite was originally laid down at the same elevation in lakes formed by obstructions in the Tertiary Fraser River. The diatomite, believed to be lower Upper Miocene in age, overlies older Tertiary clays, sands and gravels. The diatomite consists almost exclusively of various sizes of Melosira granulata diatoms, usually very small, with variable amounts of clay, silt and volcanic ash.
The Buck Ridge showing encompasses a number of separate but relatively closely spaced diatomite showings over a distance of about 6 kilometres along the west bank of the Fraser River. The diatomite is creamy white to buff with the main variable in composition being the amount of silt and ash present. Scattered thin layers of clay occur as interbeds.
The best known occurrence is on the Lepetich farm at the southeast corner of Lot 1616 and the mid-western side of Lot 8011. A test shipment of four truck loads of diatomite was taken from this location (Minister of Mines Annual Report 1960 p. 139). A sample from this vicinity (Lot 8011) analyzed 74.37 per cent Si02, 6.45 per cent Al2O3, 2.65 per cent Fe2O3, 0.71 per cent CaO, 1.30 per cent MgO and 13.26 per cent H2O (Minister of Mines Annual Report 1959 p. 166). The silica content of other diatomite exposures were generally lower, ranging from 58.28 to 76.86 per cent (Minister of Mines Annual Report 1959 p. 166).
