TY - JOUR
T1 - Mesozoic-Cenozoic paleomagnetism of the Intermontane and Yukon-Tanana terranes, Canadian Cordillera
AU - Symons, D.T.A.
AU - Harris, M.J.
AU - Mccausland, P.J.A.
AU - Blackburn, W.H.
AU - Hart, Craig
PY - 2005
Y1 - 2005
N2 - Lithoprobe Slave - Northern Cordillera Lithospheric Evolution (SNORCLE) transect support enabled 24 paleomagnetic collections (536 sites, 6547 specimens) to be made in the northern Cordillera. Paleopoles from 16 studies are integrated with other published paleopoles to present a tectonic synthesis for the Intermontane Belt (IMB) and Yukon-Tanana (YT) terranes since 215 Ma. It shows that the YT terrane has been parautochthonous with the North American craton at least since the Early Jurassic. Since 54 Ma the IMB terranes have rotated steadily clockwise at 0.29 degrees +/- 0.11 degrees/Ma on top of the YT terrane and craton or by 16 degrees +/- 6 degrees clockwise. Between 102 +/- 14 and 54 Ma, the IMB terranes rotated another 35 degrees +/- 14 degrees clockwise, probably during Paleocene collision with the craton, and were translated 8.3 degrees +/- 7.0 degrees (2 sigma) (915 +/- 775 km) northward, probably during the Late Cretaceous on the Kula plate. The 915 km estimate is much less than most paleomagnetic estimates for "Baja BC" but agrees with the geological evidence. These post-Jurassic estimates are used to reconstruct the position of the Late Triassic - Jurassic cratonic apparent polar wander path for the IMB. The resulting IMB path is found to be concordant with the Cache Creek and Quesnellia terrane poles, indicating that these terranes were together and close to the craton in the Early Jurassic. These results place the IMB terranes close to the Pacific coastline of the northern USA and southern Canada but rotated 35 degrees +/- 14 degrees counterclockwise, in the Jurassic and Early Cretaceous.
AB - Lithoprobe Slave - Northern Cordillera Lithospheric Evolution (SNORCLE) transect support enabled 24 paleomagnetic collections (536 sites, 6547 specimens) to be made in the northern Cordillera. Paleopoles from 16 studies are integrated with other published paleopoles to present a tectonic synthesis for the Intermontane Belt (IMB) and Yukon-Tanana (YT) terranes since 215 Ma. It shows that the YT terrane has been parautochthonous with the North American craton at least since the Early Jurassic. Since 54 Ma the IMB terranes have rotated steadily clockwise at 0.29 degrees +/- 0.11 degrees/Ma on top of the YT terrane and craton or by 16 degrees +/- 6 degrees clockwise. Between 102 +/- 14 and 54 Ma, the IMB terranes rotated another 35 degrees +/- 14 degrees clockwise, probably during Paleocene collision with the craton, and were translated 8.3 degrees +/- 7.0 degrees (2 sigma) (915 +/- 775 km) northward, probably during the Late Cretaceous on the Kula plate. The 915 km estimate is much less than most paleomagnetic estimates for "Baja BC" but agrees with the geological evidence. These post-Jurassic estimates are used to reconstruct the position of the Late Triassic - Jurassic cratonic apparent polar wander path for the IMB. The resulting IMB path is found to be concordant with the Cache Creek and Quesnellia terrane poles, indicating that these terranes were together and close to the craton in the Early Jurassic. These results place the IMB terranes close to the Pacific coastline of the northern USA and southern Canada but rotated 35 degrees +/- 14 degrees counterclockwise, in the Jurassic and Early Cretaceous.
U2 - 10.1139/E04-086
DO - 10.1139/E04-086
M3 - Article
SN - 0008-4077
VL - 42
SP - 1163
EP - 1185
JO - Canadian Journal of Earth Sciences
JF - Canadian Journal of Earth Sciences
ER -