New Permian paleomagnetic data from Gudong Mountain area in the Tarim Block and their tectonic implications

Paleomagnetic determinations of the Early Permian basalt rocks in the Gudong Mountain area of Tarim block (38.74N/79.7E) are presented in this paper. Stepwise thermal demagnetization successfully revealed stable characteristic residual magnetization (ChRM). Generally, reversal polarities were observed in all sampled sites in the studied section. The tilt-corrected mean directions of the Early Permian are D/I=217.7/-37.5 with α95 being 13.6 and N being 9, corresponding to a paleopole at 53.2N, 187.5E, A95=12.3. Compared with the Early Permian poles from the northwestern margin of the Tarim block, the authors hold that insignificant tectonic movement may have occurred between the interior of Tarim and its northwestern margin within paleomagnetic uncertainties. Based on the Early Permian paleopole from the Kazakhstan block and paleontological information, the authors considered that the two blocks may have collided and experienced collage in the early Cretaceous. The sea between the Tarim block and the Kazakhstan block had not vanished until the Late Permian. In association with previous studies, the authors carried out Early Permian paleogeographic reconstruction which included China's major blocks.