Industrial minerals in the Western Canada Sedimentary Basin

摘要

The Western Canada Sedimentary Basin (WCSB) covers an area of roughly 2 million km~2 and stretches over parts of the four western provinces and Northwest Territories of Canada. Its history of deposition extended from Late Proterozoic to Tertiary, during which time a sediment thickness of up to 6000 m accumulated. The basin is renowned for its mineral wealth based on fossil fuels. Less valued, but contributing significantly to this wealth are the industrial minerals, of which more than a dozen kinds are produced from the sedimentary rock succession. Palaeozoic rocks are mostly carbonates and evaporites, and give rise to rich resources of potash, salt, gypsum, sulphur, magnesite, limestone and dolomite, and formation brines. Some sili-ciclastic rocks in Lower Palaeozoic strata are sources for quartzite and silica sand. Mesozoic and Tertiary rocks are mainly elastics, and are sources for economic deposits of ceramic clay, bentonite, stone, silica sand, sand and gravel, and gemstones. Surficial deposits of Quaternary age are sources also of sand and gravel, and clay, and are the host setting for sodium sulphate deposits. Many of the industrial minerals are produced for use within the WCSB region, but some have global market significance (e.g. potash, sulphur, and magnesite). Some others that have small-scale production values but wide market distribution include dimension stone, sodium sulphate, and the gemstone ammolite. A mineral that has resource potential but no production as yet in the WCSB is diamond, found in kimberlites that intrude the sedimentary succession in several parts of the basin.