Paleomagnetic data from Early Cretaceous volcanic rocks of West Liaoning:Evidence for intracontinental rotation
Paleomagnetic data from Early Cretaceous volcanic rocks of West Liaoning: Evidence for intracontinental rotation作者机构:Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100101China Department of GeologyPeking UniversityBeijing 100871China Institute of GeologyChina Seismological BureauBeijing 100029China
出 版 物:《Chinese Science Bulletin》 (Chin. Sci. Bull.)
年 卷 期:2002年第47卷第21期
页 面:1832-1837页
核心收录:
学科分类:070903[理学-古生物学与地层学(含:古人类学)] 0709[理学-地质学] 07[理学]
主 题:Cretaceous paleomagnetism geodynamics.
摘 要:Detailed rock magnetic studies of 55 lavas from Yixian and Fuxin area, West Liaoning, show the primary carriers of remanence to be pseudo-single domain ti-tanomagnetite. K/Ar dating indicates that the volcanic sequence spans 93 to 133 Ma. Stepwise thermal demagnetization successfully isolated well-defined characteristic magnetization (ChRM) in all lavas thermal-treated above 250℃ The mean paleodirections are D/I=5.9°/58.8° (α95 = 2.9°) and D/I =179.2°/-59.9° (α95 = 5.2°) for 27 normally magnetized flows and 28 reversibly magnetized flows, respectively. It indicates that since the Early Cretaceous there is no significant horizontal movement and rotation between the Yixian-Fuxin area and Eurasia. However, Korea Peninsula may have undergone a clockwise rotation of 33.9° relative to the Yixian-Fuxin area during the Cretaceous. On the basis of characteristics of hotspot origins (core-mantle boundary or upper mantle), the clockwise rotation of Korea Peninsula relative to Eurasia is assumed to be