A PALEOMAGNETIC STUDY OF TRIASSIC SEDIMENTARY-ROCKS FROM QINSHUI BASIN, SHANXI PROVINCE, NORTH CHINA

The results of a combined paleomagnetic, rock magnetic and petrographi c study of Middle and Lower Triassic from Qinshui Basin, North China B lock are reported. The characteristic remanent magnetization from the Ermaying Formation (Middle Triassic) is carried by both magnetite and hematite. In stratigraphic coordinates, the direction (Dec. = -28 degr ees, Inc. = 44 degrees, N = 10, alpha(95) = 4 degrees) passes the (inc remental) fold test and fabric test. The corresponding paleopole is 64 degrees N, 6 degrees E. The remanent magnetization of samples from th e bottom of the Liujiagou Formation (Lower Triassic) is carried mainly by magnetite, which shows an inverse magnetic fabric and an abnormal magnetization direction. This is probably caused by a bedding-parallel compression. A comparison of Triassic paleopoles from this locality w ith others in North China reveals a significant tectonic rotation of t he eastern North China Block and Korean Peninsula with respect to the western North China Block. The rotation probably occurred during the I ndosinian Movement.