Numerous occurrences of precious metal minerals have been documented in Alberta. Gold- and platinum-group elements occur in Cretaceous to modern placer deposits throughout the province. Recent mineral production estimates by Natural Resources Canada indicates a gold production for Alberta of 30 kilograms, with a value of $1.4 million dollars for 2014. This production is mostly derived as a by-product of sand and gravel mining from placer and paleoplacer deposits. The exposed Precambrian crystalline basement in northeastern Alberta hosts many sulphide showings containing precious metals as secondary commodities, occurring in stratiform orebodies, iron-oxide breccias and veins, and shear zone–hosted quartz veins. Precious metals are also present in sediment hosted and vein occurrences in the Mountains and Foothills of Alberta and the Western Canada Sedimentary Basin.
Placer gold deposits occur in modern alluvial and glacial deposits throughout Alberta. Alberta’s alluvial gold is often called ‘flour gold’ due to its relatively small grain size, with most grains being between 125 and 250 μm, and it is sometimes accompanied by platinum-group elements, other heavy minerals, and diamonds. Alberta placer gold deposits have multiple sources, including Mesozoic to Tertiary bedrock, hydrothermal veins and replacements, reworked glacial sediments, and other preglacial fluvial deposits.
Placer gold deposits have been mined at various places in Alberta since 1861. Particularly high concentrations occur along the North Saskatchewan River in the Edmonton area and produced about 1 tonne of gold in a century. Placer gold and other heavy minerals are presently being recovered as by-products of sand and gravel operations. Elsewhere in Alberta, placer gold has been found in the Peace, Athabasca, McLeod, Red Deer, and Milk rivers.
Paleoplacer gold (± platinum-group metals, magnetite, ilmenite, rutile, and other heavy minerals) occurs in consolidated fluvial and marine-beach clastic sedimentary rocks of the Mesoproterozoic Purcell Supergroup, Lower Cretaceous Blairmore Group and Upper Cretaceous Brazeau Group in southwestern Alberta, and unconsolidated to lithified sand and gravel deposits of Tertiary to Pleistocene age throughout Alberta that predate Laurentide glaciation. These Tertiary to Pleistocene sand and gravel deposits are sources of gold recovered as a by-product preglacial sand and gravel mining.
- Placer Gold Occurrences in Alberta
- Investigation of Potential Paleoplacers in the Cretaceous Strata of the North Saskatchewan River Watershed
- Review of Metallic Mineralization in Alberta with Emphasis on Gold Potential
- Regional Metallogenic Evaluation of Alberta
- Going for gold – Alberta Energy