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TitleNailed to the craton: stratigraphic continuity across the southeastern Canadian Cordillera with tectonic implications for ribbon continent models
AuthorMcMechan, M EORCID logo; Root, K G; Simony, P S; Pattison, D R M
SourceGeology vol. 49, issue 1, 2020 p. 101-105, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20200340
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf; html
ProvinceBritish Columbia; Alberta
NTS82E; 82F; 82G; 82H; 82I; 82J; 82K; 82L; 82M; 82N; 82O; 82P; 83A; 83B; 83C; 83D; 83E; 83F; 83G
AreaCariboo Mountains; Selkirk Mountains; Purcell Mountains; Rocky Mountains; Calgary
Lat/Long WENS-120.0000 -112.0000 54.0000 49.0000
Subjectsstratigraphy; tectonics; Nature and Environment; Science and Technology; tectonic models; tectonic setting; plate margins; faulting; displacement; sutures; stratigraphic analyses; bedrock geology; basement geology; crustal structure; Canadian Cordillera; North American Craton; Belt-Purcell Supergroup; Windermere Supergroup; Neoproterozoic; Mesoproterozoic; Phanerozoic; Paleozoic; Mesozoic; Cretaceous; Jurassic; Triassic; Permian; Carboniferous; Mississippian; Devonian; Silurian; Ordovician; Cambrian; Precambrian; Proterozoic
Illustrationslocation maps; geoscientific sketch maps; stratigraphic cross-sections
ProgramOpen Geoscience
Released2020 09 18
AbstractCambrian and Upper Devonian to Mississippian strata can be confidently traced westward, without strike-slip offset, from the autochthonous section above North American basement into the southeastern Canadian Cordillera, and are thus 'nailed' to the craton. These strata are in turn stratigraphically pinned to older (Mesoproterozoic Belt-Purcell Supergroup, Neoproterozoic Windermere Supergroup, and Ediacaran), intermediate-aged (Ordovician-Silurian), and younger (Permian to Middle Jurassic) strata found only in the mountains, thus linking them to the adjacent autochthonous craton. The overlapping distribution of linking successions, regionally traceable unique stratigraphic horizons in the Belt-Purcell and Windermere supergroups, and across-strike stratigraphic features show that the entire Cariboo, northern Selkirk, Purcell, and Rocky Mountains are directly tied to the adjacent North American craton without discernible strike-slip or oblique displacement, or substantial purely convergent plate-scale (>400 km) horizontal displacement. They link the entire width of the Belt-Purcell and Windermere basins in the southeastern Canadian Cordillera to the adjacent craton and show that any proposed Cretaceous ribbon continent suture, with its thousands of kilometers of proposed displacement, cannot run through the southeastern Canadian Cordillera.
Summary(Plain Language Summary, not published)
Many different sedimentary rock units can be confidently traced from where they directly overlie and are "nailed" to unfaulted North American basement in the Plains of Alberta into and across the southeastern Canadian Cordillera. Unique cross-strike features within the sedimentary succession can also be traced across the southeastern Canadian Cordillera. Together they show there is no 100 million year old crustal suture within the southeastern Canadian Cordillera as has been proposed by some other geoscientists.

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