RELATION OF ZINC-RICH FORMATION WATERS, NORTHERN ALBERTA, TO PINE POINT ORE DEPOSIT

Brine samples collected from Middle Devonian carbonate units about 350 km southwest and downdip from the Pine Point ore body (which is also in Middle Devonian rocks) show a close compositional similarity to analyzed inclusion fluids from other Mississippi Valley type deposits. Furthermore, bottom-hole temperatures in the brine collection zone are approximately the same as filling temperatures observed for Mississippi Valley type fluid inclusions, and the brines appear to be flowing from the collection zone toward Pine Point and appear to now contain sufficient Zn to produce another deposit about half the volume of Pine Point. These features suggest that the brines represent the fluid that formed the Pine Point ore. The possibility that these brines are formation waters expelled from the Mackenzie basin through the Presqu'ile reef conduit (rather than randomly around the basin periphery) and that the metals in these brines were leached from shales of the Mackenzie basin can not be directly evaluated. However, estimates made for the Western Canada basin immediately to the south on which we have more information about composition and hydrodynamics of formation waters and the easily leachable zinc content of the shales indicate that the volume of shales present could yield 3,000 times as much Zn as is in the Pine Point ore and that expelled water water containing this Zn would be channeled through an exit conduit similar to the Presqu'ile reef. © 1969 Society of Economic Geologists, Inc.