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TitleInfluence of inclination error in sedimentary rocks on the Triassic and Jurassic apparent pole wander path for North America and implications for Cordilleran tectonics
AuthorKent, D V; Irving, E
SourceJournal of Geophysical Research vol. 115, B10103, 2010 p. 1-25,
Alt SeriesEarth Sciences Sector, Contribution Series 20100067
Mediapaper; on-line; digital
File formatpdf
Lat/Long WENS-180.0000 180.0000 90.0000 60.0000
Subjectsgeophysics; tectonics; paleomagnetic poles; tectonic interpretations; sedimentary rocks; Cordilleran; Mesozoic; Jurassic; Triassic
Illustrationslocation maps; histograms; plots; tables
ProgramTargeted Hazard Assessments in Western Canada, Public Safety Geoscience
AbstractBecause of paleomagnetic inclination error (I error) in sedimentary rocks, we argue that previous estimates of Triassic and Jurassic paleolatitudes of the North American craton have generally been too low, the record being derived mostly from sedimentary rocks. Using results from all major cratons, we construct a new composite apparent pole wander (APW) path for Triassic through Paleogene based on 69 paleopoles ranging in age from 243 to 43 Ma. The poles are from igneous rocks and certain sedimentary formations corrected for I error brought into North American coordinates using plate tectonic reconstructions. Key features of the new APW path are a 25° northward progression from 230 to 190 Ma to high latitudes (off northernmost Siberia) where the pole lingers until 160 Ma, a jump to the Aleutians followed by a hook in western Alaska by ~145 Ma that leads to the 130-60 Ma stillstand, after which the pole moves to its present position. As an example of the application of this new path we use paleomagnetic results to determine that southern Wrangellia and Stikinia (W/S), the two most westerly terranes in the Canadian Cordillera, lay 630 to 1650 km farther south than at present relative to the craton during the Late Triassic and Early Jurassic. This is consistent with an exotic Tethyan origin as paleontological and mantle geochemical evidences imply. During the Late Triassic through Early Cretaceous, W/S moved northward more slowly than the craton, implying oblique sinistral net convergence over this 130 Myr interval. This was followed by dextral shear in latest Cretaceous through Eocene.