PALEOCLIMATIC CHANGE AND NEOTECTONIC MOVEMENT IN THE TIBETAN PLATEAU

From studies on the distribution and geometric characteristic of lake; the correlation between lake belts and tectonic zones, and migration and shrinking of lakes, we obtain the following conclusion:

The neotectonic movement in the plateau is a great and violent nonformative whole uplifting tilted to the northeast.There is some internally differential relative movement in this process. The main trend of migration is to the northeast. However, local trends to the northwest, southeast or NWW direction exist. These local trends and their strength are related to the huge fold systems and strike-slip fault belt. Quaternary active faults in the plateau, especially those strike in the direction of NW, NE and North, are the most recent and active ones. They are of high seismic risk. Large earthquakes mainly occur at the intersection of these faults and the east-west main fault belts. The whole uplifting and interior differential movement in the Tibetan plateau is the result of sliding between layers in the lithosphere as well as the surface deformation caused by the collision between Indian plate and Europe-Asian plate.

The lake geometry is restricted neotectonism.This study indicates that some lakes geometry has been interacted more by the paleoclimate than by the neotectonism. On the other hand, the lake migration reflects the direction and strength of neotectonism. However, shrinking or enlarging of lake has been caused by the paleoclimate. We analysed the change of lake and found it contained many elements. The paleoclimate and the neotectonism had been affirmed by two main facts.