Occurence and Stratigraphy of some Gypsum and Anhydrite deposits in Alberta

The origin, recurrence, and utilization of gypsum and anhydrite minerals are described briefly; data on Canadian production and use of gypsum are given. Triassic gypsum deposits are present at Mowitch Creek and Fetherstonhaugh Creek in the Rocky Mountains north of Jasper.; both these deposits are tentatively correlated with the subsurface Upper Triassic evaporitic Charlie Lake formation of the Peace River area. Drill-hole data are used in geological sections to llustrate this correlation.

Middle Devonian gypsum deposits occur at Peace Point and along the Salt, Slave, and Little Buffalo Rivers, and in the subsurface at McMurray. The lower gypsum bed along the Salt, Slave, and Little Buffalo Rivers is correlated with the Chinchaga formation of northwestern Alberta, the second, third, and fourth salt beds in central Alberta, and the Meadow Lake formation of Saskatchewan. The McMurray deposit is correlated with the Pine Point and Presqu''ile formations in the Northwest Territories (also with an upper gypsum bed along the Little Buffalo River), the Muskeg formation of northwestern Alberta, possibly the lower part of the Peace Point gypsum deposit, the first salt of central Alberta and the Prairie evaporite of Saskatchewan. At least the upper part of the Peace Point deport is correlated with the Fort Vermilion member of the Slave Point formation, and is possibly equivalent to the upper part of the McMurray deposit (upper Dawson Bay equivalent). These correlations are illustrated by geological sections, isopach maps, and an interpretive facies section.

A small gypsum deposit of late Devonian age occurs at Head Creek in the Highwood Range of southern Alberta.

Chemical analyses are given for many of the deposits, and the possibility of economic development is discussed from the point of view of markets, utilization, location, transportation facilities, quality, reserves, and possible extensions of the deposits. It is oncluded that the Fetherstonhaugh Creek and Peace Point deposits are he most suitable for development in the conditions now existing. more suitable deposit might be revealed by prospecting between McMurray and Lake Claire salts in Middle Devonian strata in Alberta; Appendix B discusses the age of the Devonian evaporitic deposits and nomenclature of the strata.