The Paleomagnetical Research On Linzizong Volcanic In Shiquanhe Area, Lhasa Terrane In Paleogene

The collision of Indian plate and Eurasian plate in the field of geology are recognized as a very important tectonic events in geological history, and Lhasa terrane is located in the heart of the collision. During the past few decades, many geologists have undertaken a lot of paleomagnetism research about the Tibet Plateau and the Himalayan Orogen, especially Lhasa terrane, and get a lot of paleomagnetic data. However, there is a big controversy on the initial collision time of the Indian plate and Eurasian plate and the ancient location of Lhasa terrane before the collision. Therefore, if we can determine the ancient location of Lhasa terrane during the collision time, the above issues can be analyzed and resolved.Based on a considerable paleomagnetic study of Linzizong volcanic including 30 sample sites and 230 samples in Shiquanhe area located in western Lhasa terrane, which includes rock magnetic experiments and thermal demagnetization experiments, we can obtain the following results through the analysis and discussion of the data:1?Though the rock magnetic experiments, we can come to a conclusion that the mainly magnetic mineral of the Nianbo and Dianzhong rock is magnetite, moreover it includes some pyrrhotite.Then, we come to the average direction of high temperature component by analysising the thermal demagnetization experimental data is:Ds=26.2°,Is=22.9°, Ks=22.2, ?95s=9.0°and Ds=20.8°, Is=1.8°, Ks=39.6°, a95g=6.4°.While the direction of low temperature component is nearly same to that of modern geomagnetic field, which may be result of remagnetization by modern geomagnetic field. Finally, we come to an average direction of high temperature component of Linzizong volcanic:Dg=31.4°, Ig=56.8°, Kg=12.5°, a95g=7.7°; Ds=24.6°, Is=14.6°, Ks=12.3°, a95s=7.8°.Paleomagnetic pole positioncalculated is:?(°N)=56.4°,? (°E)=211.7°, dp=8.0, dm=4.1,??=7.4°N.2?Compared with the previous paleomagnetic data, We can suggest that Lhasa terrane during Cretaceous -Paleogene has been at the low latitudes of the Northern Hemisphere, approximately in the range of 10°?15°N, and does not occur significant drift.