THE PALEOMAGNETIC STUDY OF THE QUANJI GROUP (SINIAN) OF THE CHAIDAM TERRANE
Li Yianping Michael McWilliams Tan Chengzhe (Department of Geophysics Stanford (Beijing Graduate School Wuhan University Stanford, CA94305 U.S.A.) College of Geology Beijing, China)
Paleomagnetic data from the Quanji Group of Late Precambrian ( Sinian ) age have been obtained from the Chaidam terrane. Directions of magnetization from six sites spanning 600 m.y. to 700 m.y. give a mean direction of Dec. = 115.3°, Inc.=0.8, K=6.1, α95=29.6° after tilt correction. Both magnetic polarities are present The equatorial latitude of the Quanji Group is consistant with that of the Tarim craton during the Sinian, Suggesting that the Chaidam terrane probaly had an affinity with the Tarim craton. Since the Quanji Group is stratigraphi-cally below the lower Cambrian tillite of the Xiaogaolu Group, the paleomagne-tic data imply that the Xiaogaolu Group tillite also formed in low latitudes.