FISSION TRACK AGES AND UPLIFT RATES OF THE SOUTH XIZANG (TIBET) REGION

The geological ages of Lhasa, Kangmar and Gaowu rock bodies of Xizang (Tibet) have been determined by fission track method. The results are: 25.5—27.2, 10.7—11.5, 8.06—9.19 Ma respectively. It is found that the fission track (FT) age of apatite increases with the elevation of sample. Calculated by the ages-topographic altitude method, the uplift rates of the above three rock bodies are 0.25, 0.45, and 0.49 mm/a respectively. On the basis of the fission track age and the published isotopic age data, the uplift rates of other regions have been calculated by the mineral pair-blocking temperatures method. The lowest is 0.08 mm/a and the highest 2.4 mm/a. We found that the uplift rates of different regions in the same period are distinet, and the uplift rates of different geological times in the same region also are not alike. This situation shows that the Xizang region has a complex geological and unroofing history due to the collision of the India and Eurasian plates.

FISSION TRACK AGES AND UPLIFT RATES OF THE SOUTH XIZANG (TIBET) REGION