The 142 Ma old Jurassic Topley Intrusions are exposed in the middle of the Intremontane Belt or Stikinia subterrane of composite Terrane I of the Canadian Cordillera in central British Columbia. Thermal demagnetization at 560¿C leads to the isolation of a single stable magnetic component directed at 324.2≡, 54.1¿, &agr;95=8.6¿ in 17 of the 22 sites. The pole position of 238.2¿W, 58.4¿N, Δp=8.3¿, Δm=11.8¿ for the component is discordant relative to the North American Craton. This position supports previous work in suggesting that Stikinia have been translated northward by 14¿2¿ or about 1400 km between mid-Cretaceous and pre-Miocene time. It also suggests that the center portion of Stikina has been rotated about a vertical axis by a statistically significant amount whereas minor marginal blocks of the subterrane have been subjected to large and variable amounts of both clockwise and counter-clockwise rotation. |