STRUCTURAL EVOLUTION OF THE PORCUPINE CREEK ANTICLINORIUM, WESTERN MAIN RANGES, ROCKY-MOUNTAINS, BRITISH-COLUMBIA

Authors
Citation
Wh. Lickorish, STRUCTURAL EVOLUTION OF THE PORCUPINE CREEK ANTICLINORIUM, WESTERN MAIN RANGES, ROCKY-MOUNTAINS, BRITISH-COLUMBIA, Journal of structural geology, 15(3-5), 1993, pp. 477
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary
ISSN journal
0191-8141
Volume
15
Issue
3-5
Year of publication
1993
Database
ISI
SICI code
0191-8141(1993)15:3-5<477:SEOTPC>2.0.ZU;2-C
Abstract
The structure of the Western Main Ranges of the Canadian Rockies is do minated by the Porcupine Creek anticlinorium. The anticlinorium develo ped by internal deformation of thrust sheets formed above relatively f lat decollement horizons. Deformation continued by a downward stepping of decollement horizons. Earlier decollements, formed at a high struc tural level, were folded and the thrust sheets above redeformed by con tinued deformation on deeper, later decollement horizons. The successi ve decollement horizons occurred not only deeper but also in a more no rthward location, leaving deformation in only stratigraphically higher positions in the south, but producing deeper structures to the north. This northward progression of decollement horizons requires that the Porcupine Creek anticlinorium grew diachronously from south to north w ith earlier structures preserved in the south and later ones developed in the north. Motion on each decollement horizon produced an addition al phase of deformation in the rocks above it. However, additional str uctures could only develop locally where pre-existing structures were at sufficiently high angles to the orientation of incipient structures . Elsewhere the previous anisotropy prevailed and early phase structur es were tightened with no evidence of the later phase.