Clockwise rotations recorded in Early Cretaceous rocks of South Korea: implications for tectonic affinity between the Korean Peninsula and North China

Recent interest has focused on whether South Korea may have undergone varia ble tectonic rotations since the Cretaceous, Tn an effort to contribute to the answer to this question, we have completed a palaeomagnetic reconnaissa nce study of Early Cretaceous sedimentary and igneous rocks from the Kyongs ang basin in southeast Korea, Stepwise thermal demagnetization isolated wel l-defined characteristic magnetization in all samples. The palaeomagnetic d irections reveal patterns of increasing amounts of clockwise (CW) rotation with increasing age for Aptian rock units. Palaeomagnetic declinations indi cate clockwise vertical-axis rotations of R = 34.3 degrees +/- 6.9 degrees for the early Aptian rock unit, R = 24.9 degrees +/- 10.6 degrees for the m iddle Aptian, and R = -0.9 degrees +/- 11.8 degrees for the late Aptian rel ative to eastern Asia. The new Cretaceous palaeomagnetic data from this stu dy are consistent with the hypothesis that Korea and other major parts of e astern Asia occupied the same relative positions in terms of palaeolatitude s in the Cretaceous, An analysis of and comparison with previously reported palaeomagnetic data corroborates this hypothesis and suggests that much of Korea may have been connected to the North China Block since the early Pal aeozoic. A plausible cause of the rotation is the westward subduction of th e Kula plate underneath the Asian continent, which is inferred to have occu rred during the Cretaceous according to several geological and tectonic ana lyses.