Paleomagnetic results from the lower Mesozoic Daedong Supergroup in the Gyeonggi Block, Korean Peninsula: an eastern extension of the South China Block

Lower Mesozoic lake deposits in the Daedong Supergroup of the Gyeonggi Bloc k were collected at 38 sites for paleomagnetic study. A remanent magnetizat ion component with unblocking temperatures of 635-660 degrees C (component A) was isolated from four sites. The directions of this component with both normal and reversed polarities yielded positive fold and reversal tests at the 95% confidence level. Component A is interpreted to be of primary orig in of Late Triassic time. The mean direction of component A (D = 82.2 degre es, I = 23.1 degrees with alpha(95) = 4.10), together with previously repor ted primary directions, yields a pole representative for the Gyeonggi Block at 31.9 degrees N, 220.2 degrees E (A(95) = 12.7 degrees). The paleomagnet ic pole shows good agreement with that for the South China Block, suggestin g that the Gyeonggi Block has been part of the South China Block. The Gyeon ggi Block, as the eastern part of the South China Block, is regarded to hav e thrust to its position at the present Korean Peninsula during the collisi on between the North and South China Blocks. (C) 2000 Elsevier Science B.V. All rights reserved.