Further paleomagnetic results from the ~ 155 Ma Tiaojishan Formation, Yanshan Belt, North China, and their implications for the tectonic evolution of the Mongol–Okhotsk suture

摘要: Abstract A new paleomagnetic study on well-dated (~ 155 Ma) volcanic rocks of the Tiaojishan Formation (Fm) in northern margin North China Block (NCB) has been carried out. total 194 samples were collected from 26 sites Yanshan Belt areas Luanping, Beipiao, and Shouwangfen. All subjected to stepwise thermal demagnetization. After removal a recent geomagnetic field viscous component, stable high temperature component (HTC) was isolated. The inclinations our data are significantly steeper than those previously published Fm Chengde area ( Pei et al., 2011 , Tectonophysics, 510, 370–380). Our analyses demonstrate that directions obtained each sampled strongly biased by paleosecular variation (PSV), but PSV can be averaged out combining all virtual poles (VGPs) region. mean pole at 69.6°N/203.0°E (A95 = 5.6°) passes reversal test regional tilting 95% confidence is thus considered as primary record. This newly determined consistent with available Late Jurassic red-beds southern part NCB, they incompatible coeval Siberia reference Eurasia, indicating convergence between NCB had not yet ended ~ 155 Ma. calculation shows ~ 1600-km latitudinal plate movement crustal shortening after In addition, no significant vertical axis rotation found either or major