Outcrop(!) of the Week – Baldonnel Beauty
If this Petro Ninja – Enlighten Geoscience Well of the Week series entry on formations associated with the Peace River Arch followed the usual format, an article on the Baldonnel would drone on with some rote recitation of a Bullmoose well with over 133 bcf of cumulative gas production (although referring to a well in the Foothills in a series in the Peace River Arch is kind of cheating) or the top cumulative oil producer from the Birch pool.
But that opening paragraph was just a head fake as we introduce a new facet into the series. Cool outcrops. Outcrops that help you realize just how complex the subsurface geology is. Outcrops that reinforce how important field trips are and the value of time spent looking at core.
In the subsurface of the Peace River Block, the Baldonnel is thought of as a subcrop play of limited extent due to being the oldest of the four Triassic dolostone/argillaceous limestone units underlying the sub-Jurassic Unconformity.
Sequence stratigraphic cross section illustrating complex relationship of bounding and internal unconformities. Davies (1997)
As displayed by Gibson (1993), the Baldonnel is well worth seeing in outcrop. The dolomite muds are definitely present as seen in well data but there are also extensive coquina channels. Check out the images from his paper below:
It’s a shame that all of the images are reproductions of scanned black and white photographs. I suppose someone could organize a field trip to go see them in living colour…
Davies, G. R., 1997. The Triassic of the Western Canada Sedimentary Basin: tectonic and stratigraphic framework, paleogeography, paleoclimate and biota. Bulletin of Canadian Petroleum Geology. V. 45 (4): 434–460. doi: https://doi.org/10.35767/gscpgbull.45.4.434.
D.W. Gibson; Upper Triassic Coquina Channel Complexes, Rocky Mountain Foothills, Northeastern British Columbia. Bulletin of Canadian Petroleum Geology 1993; 41 (1): 57–69. doi: https://doi.org/10.35767/gscpgbull.41.1.057.