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 Block were collected at 38 sites for paleomagnetic study. A remanent magnetization component with unblocking temperatures of 635–660°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 origin of Late Triassic time. The mean direction of component A (D=82.2°, I=23.1° with α95=4.1°), together with previously reported primary directions, yields a pole representative for the Gyeonggi Block at 31.9°N, 220.2°E (A95=12.7°). The paleomagnetic pole shows good agreement with that for the South China Block, suggesting that the Gyeonggi Block has been part of the South China Block. The Gyeonggi Block, as the eastern part of the South China Block, is regarded to have thrust to its position at the present Korean Peninsula during the collision between the North and South China Blocks.