Eric Walter Mountjoy

Eric Walter Mountjoy was uniquely proficient in both the microscopic world of carbonate sedimentology and the grand scale of mountain-building tectonics. Born in Calgary and raised at the doorstep of the Rockies, he earned his B.A.Sc. at UBC (1955) and PhD at the University of Toronto (1960) on the stratigraphy and structure of the Mount Robson area; work that won the CSPG Best PhD Thesis Award and laid the foundation for his dual expertise.

Upper Devonian reefs. Mountjoy revolutionised understanding of the reef complexes of the Canadian Rockies. At the Miette and Ancient Wall complexes in Jasper National Park, he demonstrated that reefs were dynamic systems controlled by episodic sea-level change. He proved early submarine cementation (the “hard-rock” model) made reefs rigid rather than loose debris piles, and pioneered the “reciprocal model”; reef growth during highstands, basinal muds during lowstands. His surface mapping provided the oil and gas industry with the gold-standard analogue for Leduc-age reservoirs in the Alberta Basin subsurface.

Operation Bow-Athabasca (1965–1966). With Raymond A. Price, Mountjoy co-led the GSC’s helicopter-supported regional mapping project between Banff National Park and Jasper. Their classic cross-sections depicted the Rockies as a thin-skinned fold-and-thrust belt; layers peeled off the basement and stacked like shingles. The Bow-Athabasca transect showed that the Main Ranges around Lake Louise and the Continental Divide were laterally transported, not simply vertical uplifts. Mountjoy’s maps of the Mount Robson area remain the definitive structural interpretation. His ability to visualise 3D structures in high-relief alpine terrain was legendary; modern GPS has confirmed the accuracy of his hand-drawn 1:50,000 lines.

McGill and legacy. Mountjoy joined McGill in 1963 and served for over 45 years, holding the Logan Professorship (1993–1998). He directed more than 50 Master’s and Doctoral students; many became industry executives or professors. He bridged academic sedimentology and practical structural mapping, maintaining deep collaboration with the GSC. The Mountjoy–Price transect remains the baseline against which all new Cordilleran research is measured; for landslide assessment, petroleum exploration, or tectonic studies.