Geochemistry of Groundwater and Springwater in the Paskapoo Formation and Overlying Glacial Drift, South-Central Alberta

The Paskapoo Formation contains approximately one-third of all water wells present in the Canadian Prairies, illustrating its importance as a source of groundwater in central and southern Alberta. Our report describes and interprets the results of chemical analyses of groundwater and springwater samples collected from the Paskapoo Formation and overlying glacial drift between June and September of 2009. Our samples represent an east-west transect across the outcrop/subcrop area of the Paskapoo Formation, bounded by Ponoka in the north and Crossfield in the south.

Groundwater in the Paskapoo Formation and overlying glacial drift shows lateral and vertical changes in geochemistry within our study area. Lateral changes from west to east include increasing concentrations of dissolved solids, dissolved Na, dissolved SO₄ and alkalinity and decreasing concentrations of dissolved Ca and ¹⁴C_(DIC) . Dissolved O₂ concentrations, with the exception of one groundwater sample, were all <3.0 mg/l and most were <0.01 mg/l.

Vertical changes in groundwater geochemistry within the Paskapoo Formation are, in some instances, more subtle than lateral changes. Field pH values generally increase and concentrations of dissolved Ca and dissolved Mg generally decrease with depth.