Paleomagnetism of ca. 1.35 Ga sills in northern North China Craton and implications for paleogeographic reconstruction of the Mesoproterozoic supercontinent

We report paleomagnetic data on precisely dated Mesoproterozoic sills, in zircon and baddeleyite 207Pb/206Pb ages of 1345 ± 12 and 1353 ± 14 Ma respectively, intruding the Xiamaling and Wumishan formations in North China with an aim of evaluating how the North China Craton (NCC) was involved in the evolution of the Columbia supercontinent from ca. 1.78 to 1.35 Ga. After systematic thermal demagnetization we isolate a high temperature characteristic remanence from 18 sites with a tilt-corrected site-mean direction of D = 294.4°, I = −31.7° and α95 = 4.3°, corresponding to a mean paleomagnetic pole at λ = 5.9°N, φ = 359.6°E (N = 18) with angular standard deviation of 10.0° and A95 = 4.3°. Rock magnetic experiments, light microscopy and scanning electron microscopy all indicate that the main magnetic minerals in the sampled sill rocks are medium sized titanomagnetites. The positive fold test and fresh titanomagnetite grains suggest that the characteristic remanence is likely to be a primary acquired at ca. 1.35 Ga. The preliminary paleogeography reconstruction based upon the well-matched apparent polar wander paths between the Laurentia–Baltica–Siberia united block and the NCC supports the interpretation that the NCC may have drifted together with this united block before ca. 1.35 Ga during the late history of the Columbia supercontinent. We argue that the NCC was located in low latitudes and kept tight connections with the Siberian and Indian cratons during the interval between ca. 1.8 and 1.35 Ga, and that the ca. 1.35 Ga sills widely developed in the Mesoproterozoic Xiamaling and Wumishan formations, as well as the ca. 1.3–1.2 Ga magma events well-developed in Siberia and northern margin of the NCC, may represent the complete fragmentation of the NCC with the neighboring cratons.

► A high quality 1.35 Ga paleomagnetic pole was reported from a suit of precisely dated sills for the North China Craton (NCC).
► The NCC was very likely located in low latitudes with a tight connection to Siberia and India by ca. 1.35 Ga.
► Complete fragmentation of the NCC with neighboring cratons may occur at around ca. 1.3–1.2 Ga.