Three types of halite are recognized in the Prairie Evaporite Formation (First Salt) of central Alberta, and are named clear, chevron, and brown. Clear halite occurs throughout the formation, while chevron and brown halite are restricted. Chevron halite, on the basis of texture and bromide content, is considered primary.

The bromide content of clear halite in the lower part of the Prairie Evaporite Formation increases upwards from the base of the formation. In the upper part of the formation there is an upward decrease in the bromide content of clear and brown halite. Clear halite has a consistently higher bromide content than associated brown halite.

Halite units alternating with anhydrite units, in the middle of the Prairie Evaporite Formation, are called seasonal layers. Bromide values, obtained from analyses of successive chevron and clear halite grains within these halite units, bear no simple relationship to the seasonal layers.

The clear halite of the two lower salts, the Cold Lake and Lotsberg Formations, is similar in appearance to the clear halite of the Prairie Evaporite Formation, but lacks analytically detectable quantities of bromide. This halite could not have formed through precipitation from unaltered sea water; nor could it have formed through precipitation from sea water saturated by dissolving previously precipitated halite. This clear halite probably results from the solution, and subsequent deposition, of halite by fresh water. Solution of the original halite by fresh water probably occurred before deposition of the Prairie Evaporite Formation, as it shows no evidence of solution by fresh water. Solution may have been caused by suface runoff percolating down, or by fresh ground water discharging upward.

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