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TitleTracking the Late Jurassic apparent (or true) polar shift in U-Pb-dated kimberlites from cratonic North America (Superior Province of Canada)
AuthorKent, D V; Kjarsgaard, B AORCID logo; Gee, J S; Muttoni, G; Heaman, L M
SourceGeochemistry, Geophysics, Geosystems (G3) vol. 16, issue 4, 2015 p. 983-994, Open Access logo Open Access
Alt SeriesEarth Sciences Sector, Contribution Series 20150057
Mediapaper; on-line; digital
File formatpdf
ProvinceOntario; Manitoba; Northwest Territories; Nunavut; Northern offshore region
NTS41; 42; 43; 53; 54; 55; 56; 57; 58; 59; 63; 64; 65; 66; 67; 68; 69; 76; 77; 78; 79; 86; 87; 88; 89; 96; 97; 98; 99; 106; 107; 116; 117
AreaArctic; Canada; United States of America
Lat/Long WENS-152.0000 -88.0000 85.0000 35.0000
Subjectsgeochronology; polar wandering; uranium lead dates; uranium lead dating; kimberlites; paleomagnetic poles; paleomagnetism; paleomagnetic interpretations; Superior Province; Mesozoic; Jurassic
Illustrationslocation maps; plots
ProgramGEM: Geo-mapping for Energy and Minerals Diamonds
Released2015 04 02
AbstractDifferent versions of a composite apparent polar wander (APW) path of variably selected global poles assembled and averaged in North American coordinates using plate reconstructions show either a smooth progression or a large (~30°) gap in mean paleopoles in the Late Jurassic, between about 160 and 145 Ma. In an effort to further examine this issue, we sampled accessible outcrops/subcrops of kimberlites associated with high-precision U-Pb perovskite ages in the Timiskaming area of Ontario, Canada. The 154.9?±?1.1 Ma Peddie kimberlite yields a stable normal polarity magnetization that is coaxial within less than 5° of the reverse polarity magnetization of the 157.5?±?1.2 Ma Triple B kimberlite. The combined ~156 Ma Triple B and Peddie pole (75.5°N, 189.5°E, A95?=?2.8°) lies about midway between igneous poles from North America nearest in age (169 Ma Moat volcanics and the 146 Ma Ithaca kimberlites), showing that the polar motion was at a relatively steady yet rapid (~1.5°/Myr) pace. A similar large rapid polar swing has been recognized in the Middle to Late Jurassic APW path for Adria-Africa and Iran-Eurasia, suggesting a major mass redistribution. One possibility is that slab breakoff and subduction reversal along the western margin of the Americas triggered an episode of true polar wander.
Summary(Plain Language Summary, not published)
Integrated age determinations and paleomagnetic data are used to examine earth-scale plate tectonic processes during the time period 160 to 145 Ma.

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