ABSTRACT: The Distribution and Morphology of Middle Devonian Winnipegosis Reefs in Southern Saskatchewan

SPARKS, DWAYNE, University of Regina, Regina, Saskatchewan, Canada

Middle Devonian Winnipegosis reefs are found throughout the Elk Point basin in Saskatchewan. Their distribution is of interest to potash producers (who wish to avoid them) and petroleum producers (who wish to find them). The purpose of this study is to determine the factors controlling reef distribution and morphology. Over 800 wells have penetrated the Winnipegosis Formation in Saskatchewan. For information retrieval and mapping, a database of this size is best handled by computerization. All well files are accessible through a CD-ROM disk, making the information readily applicable to PC spreadsheet and mapping software.

The Winnipegosis Formation consists of a lower, carbonate platform member and an upper member represented by a carbonate buildup. Two extensively drilled reefs, one in the subsurface of southeastern Saskatchewan and the other in the outcrop belt of Manitoba, demonstrate that the buildups were initiated by a stabilization biota dominated by crinoids. Continued growth was effected through the accumulation of peloids, lime mud, codiacean algae, and crinoid remains. A climax community of fasiculate and tabulate corals, red algae, microbialites, and in places stromatoporoids marks the final growth phase.

The discovery of hydrocarbons in the Winnipegosis Formation in southeastern Saskatchewan has greatly increased the well control in that area, making it an ideal region to begin a study of this nature. Computer-generated structural, paleostructural, and isopach maps show that some linear trends may have influenced the sites of growth of the stabilization biota.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)