Paleomagnetism of early Paleozoic volcanic rocks from the Beishan area,Gansu of northwest China:Preliminary insight into early Paleozoic kinemics of the Beishan terrane

We report rock magnetic and paleomagnetic results for Middle Silurian Gongpoquan and Middle Ordo-vician Huaniushan volcanic samples collected from the Ma-zongshan and Hongliuyuan areas of Gansu Province, northwest China. The results indicate that the main magnetic mineral of the Gongpoquan and Huaniushan volcanic rock is magnetite, and it may remain characteristic remanent magnetization acquired at the time of formation of the rocks. However, with the exception of samples from site go20, most of Middle Ordovician Huaniushan volcanic samples have a very weak nature remanent magnetization, and generally show an erratic demagnetization behavior, which does not allow isolation of characteristic remanent magnetizations from these samples. Comparison of paleomagnetic results obtained from the Beishan area of Gansu with Paleozoic apparent polar wander paths for Tarim and Siberia suggests that the Beishan tarrane, the southern part of the Beishan area of Gansu beyond the Mingshui-Shipanjin-Xiaohuang-shan zone, a