Stoakes Consulting Group Ltd

Suite 402, 103 - 10th Avenue NW, Calgary, AB, Canada T2M 0B4
ph: (403) 262-6003  fax: (403) 265-4662   email: Replica Longines

Stratigraphic Analysis of the Upper Elk Point Group – Rainbow Basin, NW Alberta


The Rainbow basin in north western Alberta is a small deep evaporitic basin that formed behind the extensive Presqu’ile barrier reef complex. Deposition is characterized by isolate pinnacle reefs encased in evaporitic deposits and surrounded by a fringing shelf-bank system. Keg River carbonates mark the first fully open marine incursion into the basin. A low energy carbonate ramp formed during the initial stage of Keg River transgression, locally forming shoals upon the which Middle Keg River reefs subsequently developed. A period of basin restriction and evaporative drawdown followed with deposition of the Black Creek salt occurring in the basin centre, thinning against topography of the Middle Keg River shelf margins and buildups. Open marine conditions became re-established during the Upper Keg River with preferential accumulation of carbonate sediments on sites of earlier Middle Keg River reef growth. Once again the basin became restricted and was infilled with a thick series of interbedded evaporites and carbonates of the Muskeg Formation. Finally, shallow water shelf carbonates of the Sulphur Point blanketed the basin completing the Upper Elk Point Group depositional cycle.

This study provides a detailed understanding of the paleogeography of the Rainbow basin, identifying and classifying pools according to their play-type, and highgrades areas of exploration potential based on these play types. The result is a complete geological assessment of the Rainbow basin in which areas of high exploration potential are identified and rank according to their prospectivity.

The study area is located in north western Alberta from Townships 106 to 111 between Ranges 3W6 and 12W6. The study incorporates an 848 well database selected from a total of 857 wells that penetrated the Muskeg Formation or deeper at the time of the study. In addition core from 283 wells were examined at the AEUB Core Research Centre.



  • fully illustrated text (52 pages, plus colour and B&W figures) documenting stratigraphy, depositional setting, play types, exploration potential, core descriptions, and database;
  • 12 structural cross sections illustrating exploration play types;
  • 2 stratigraphic cross sections;
  • 9 maps (isopach & structure) at 1:100,000 scale;
  • 17 stratigraphic picks from Top Slave Point Fm. to Top PreCambrian, including 3 internal Keg River Fm. and 5 internal Muskeg Fm. picks.;
  • 848 well database available in digital and hardcopy formats;
  • cored intervals from 283 wells described with internally consistent correlations;

For more information or to arrange a technical presentation, call (403) 262-6003, fax (403) 265-4662 or email: