CSPG13FT Turtle Mountain (Crowsnest Pass) Structure trip “The Rise and Fall of Turtle Mountain”
The Turtle Mountain Anticline is a modified fault-propagation fold, which formed an east-verging anticline with an overturned forelimb of competent Paleozoic carbonates, with softer Mesozoic shales, sandstone, and coal in the footwall below and in front of it. Subsequent uplift and differential erosion created a very steep slope which eventually collapsed in April 1903. The resulting rock slide destroyed the southern edge of the town of Frank; hence its name: “The Frank Slide.” Many combinations of factors have been proposed as a possible trigger for the Frank Slide: slope angles with respect to bedding and/or joint surfaces, the weather, footwall erosion, earthquakes, and coal mining.
This field trip will visit outcrops of the Turtle Mountain Thrust and the main Kootenay Formation coal seam; two geological features which rule the stability of the mountain. In addition, we will visit outcrops of the Palliser Formation in the core of the Turtle Mountain Anticline, which show good porosity indicating that these rocks could be good reservoirs. The Mississippian rocks located in a tectonic horse between the Turtle Mountain Thrust and a splay are folded on a large scale. The fold axes have been rotated approximately 30 degrees clockwise, which sense of movement is confirmed by offsets of chert bands within the Mount Head Formation.
Fracture fabrics of these carbonates were measured in outcrop and obtained from image logs in a borehole. The majority of fractures are extension fractures with accompanying shear fractures related to the anticlinal fold. Two main types of present-day slope failures can be distinguished: sliding and toppling. On the East slope of Turtle Mountain, joints (including neotectonic joints) are dipping sub-parallel to the topography. At South Peak bedding is also dipping in the same direction causing the slope, joints and bedding to align. This could result in a major rock slide towards Bellevue. Sliding and toppling of blocks at North Peak (above the town of Frank) will generally be smaller in volume then at South Peak, because bedding is not parallel to the slope of the mountain in this area.
- - - - - - - - - - - - - - - -
Willem Langenberg is presently the principal researcher of Long Mountain Research Inc. and an Adjunct Professor at the University of Alberta. Before that, he worked for the Alberta Geological Survey for almost 35 years. He obtained a Ph.D. in structural geology from the University of Amsterdam in the Netherlands in 1973. He was previously employed by the University of Amsterdam, the University of Alberta, Alberta Research Council, Alberta Department of Energy and the Energy Resources Conservation Board.
He has had a longstanding career in structural geology, with emphasis during the last thirty years on economic geology (including energy and mineral resources). He performed the function of Project Control Officer on the inter-governmental Turtle Mountain Monitoring Project from 2003-2005. He is presently conducting investigations on the geology of Turtle Mountain (Crowsnest Pass), dating of Cretaceous and Tertiary bentonites, Coal-bed methane (CBM) and CO2 Capture and Storage (CCS). He authored or co-authored 35 refereed articles in scientific journals, 4 AGS Bulletins and many AGS reports/maps.
He is a member of APEGGA, the Geological Association of Canada, the Canadian Society of Petroleum Geology and the Geological Society of America. He was Publication Manager of the Edmonton Geological Society from 1993-2003.
Tijmen (or Tim) Hartel finished his Masters Degree (Drs.) from the Vrije Universiteit in Amsterdam in 1988 and another one from the University of Calgary in 1993. After working in the environmental industry and gaining experience assisting a consultant and as a well-site geologist, he was hired by Suncor Energy in 1997 to determine depositional environment, stratigraphy, porosity and permeability from drill cuttings. The relationship between small scale observations and production in conventional and unconventional reservoirs is his main interest.
