Preliminary Paleomagnetics Results of Study on the Middle Cambrian tn the Region of East Edge of the Alashan and Hexi Corridor Terrane

Abstract

AbstractBy middle Cambrian 107 orientated drill‐core samples over 15 sites in the east edge of the Alashan and Hexi Corridor terrane in. Era, detailed paleomagnetic and rock magnetic studies are presented. Results show that magnetite was the predominant magnetic mineral, and the characteristic high temperature component B4 passed fold test at a 95% confidence level. The tilt‐corrected directions of this component significantly differ from that of post‐Silurian results for the North China Block and the Alashan and Hexi Corridor terrane. The corresponding paleomagnetic pole, at 349.9ºE, 21.1ºN with A95 = 14.9º, is located close to those of the North China Block, indicating that no distinct latitudinal displacement took place between the Alashan and Hexi Corridor Terrane and the North China Block since the middle Cambrian. However, the Alashan and Hexi Corridor terrane may have counterclockwise rotation of about 15º with respect to the North China Block during the middle Cambrian to late Cambrian. This rotation is probably indicative of the accreting course of the Alashan and Hexi Corridor terrane to the west of the North China Block, and then one integral North China Block was formed in the late Cambrian.