Henry Lickorish - Structural Geology
Calgary, Canada
tel: +1 250 213 2643
Structural evolution of the Porcupine Creek Anticlinorium, Western Main Ranges, Rocky Mountains, British Columbia
W.H. Lickorish 1993
Journal of Structural Geology, 15, 477-489.

The structure of the Western Main Ranges of the Canadian Rockies is dominated by the Porcupine Creek Anticlinorium. The anticlinorium developed by internal deformation of thrust sheets formed above relatively flat décollement horizons. Deformation continued by a downstepping of décollement horizons. Earlier décollements, formed at a higher structural level, were folded and the thust-sheets abvove redeformed by continued deformation on deeper, later décollement horizons. The successive décollement horizons occurred not only deeper, but in a more northward location, leaving deformation in only stratigraphically higher positions in the south, but producing deeper publications to the north. This northward progression of décollement horizons requires that the Porcupine Creek Anticlinorium grew diachronously from south to north with earlier publications preserved in the south and later ones developed in the north. Motion on each décollement horizon produced an additional phase of deformation in the rocks above it. However, additional publications could only develop locally where pre-existing publications were at sufficiently high angles to the orientation of incipient publications. Elsewhere the previous anisotropy prevailed and early phase publications were tightened with no evidence of the later phase.