New paleomagnetic results from the Yangzhuang Formation of the Jixian System, North China, and tectonic implications

A paleomagnetic study was carried out on the Yangzhuang Formation （1350 Ma） of the Jixian System in the North China Block （NCB）. Detailed stepwise thermal demagnetization isolated two components. The soft compo- nent （component A） was interpreted as a remagnetization in the recent geomagnetic field. The hard component （compo- nent B） with higher unblocking-temperatures was carried by hematite. Its site-mean direction is D/I = 77.6°/-24.3° （κ = 5.4, α95 = 18.3°, N = 15 sites） before, and D/I = 72.2°/11.5° （κ = 24.6, α95 = 7.9°） after tilt correction. It passes a fold test （Mesozoic folding） at 99% confidence level and reversal test at 95% confidence level. The corresponding pole locates at 17.3°N, 214.5°E （dp = 4.1°, dm = 8.0°）. A best fit of paleo- magnetic poles from the NCB, Baltica, Siberia and the ap- parent polar wander path for Laurentia suggests a long-lived connection between these paleo-continents between 1800 and 1350 Ma.