从浪卡子至雅鲁藏布江逆冲带剖面中获得的 4个磷灰石裂变径迹年龄为 13.6— 17.2Ma ,记录了区内陆 -陆碰撞的时代 ,而这恰恰有别于前人的资料。磷灰石裂变径迹年龄与样品高程呈负相关关系 ,表明陆 -陆碰撞伴随有快速的抬升 ,其抬升速率为 176m/Ma。 13.6Ma以来的剥蚀量约为 2 .9km ,冷却速率和剥蚀速率分别约为 7℃ /Ma和 2 13m/Ma。 3个锆石裂变径迹年龄值相差较大 ,χ2 检验值约为 0 .1%,证实该区陆内造山作用是在低温状态下进行的。 Four apatite fission tracks obtained from the Longkar to the Brahmaputra thrust belt profile are 13.6-17.2 Ma, which record the time of continental-continental collision in the area, which is different from the previous data. The apatite fission track age is negatively correlated with the sample elevation, indicating a rapid uplift of land-continent collision with an uplift rate of 176 m / Ma. The erosion amount since 13.6Ma is about 2.9km, and the cooling rate and erosion rate are about 7 ℃ / Ma and 21.3m / Ma, respectively. The three zircon fission track age values ​​are quite different, and the χ2 test value is about 0.1%, confirming that intracontinental orogeny was carried out at low temperature.