A Paleomagnetic Reconnaissance of Permian to Cretaceous Sedimentary Rocks in Southern Part of Korean Peninsula

Abstract

Paleomagnetic results have been obtained from ten Korean sedimentary rock formations ranging in age from Permian to Cretaceous. The magnetizations of almost all the rocks from Permian to Jurassic formations have been severely overprinted. Estimation of paleomagnetic direction of the period between Permian and Jurassic is hindered by this. The Cretaceous rocks from the Gyeongsang Supergroup, however, have recorded the paleomagnetic direction at the period of formation of sedimentary rocks during Cretaceous. Some strata in the Hasandong Formation of lower part of the Gyeongsang Supergroup show the reversed magnetization which is presumably ascribed to reversed magnetic polarity epoch of M-series in Mesozoic polarity scale. Paleomagnetic direction of the upper part of the Gyeongsang Supergroup (Middle to Late Cretaceous) is estimated to be Dec=28.4°, Inc=58.2° and α95=6.4°. The pole position of Middle to Late Cretaceous obtained for the Korean Peninsula (202°E, 67°N) is in good agreement with other Cretaceous data for the Asian continent, implying that the Korean Peninsula has not been subjected to rotational movement relative to the Asian continent since Cretaceous. © 1986, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.