青藏高原东缘甘孜地区新生代隆升过程之磷灰石裂变径迹证据

Apatite fission track evidence for the Cenozoic uplift process in Garze area on the eastern margin of the Tibetan Plateau

通过青藏高原东缘甘孜地区7件砂岩磷灰石样品裂变径迹分析,取得了测试样品的表观年龄,运用模拟退火法对所有样品进行了热史模拟,获得了样品的热演化史;分析出甘孜地区在新生代古近纪以来经历了相似的构造演化过程,强构造隆升阶段分别发生在古近纪46～30 Ma间和新近记9 Ma以来,平均抬升速率和平均抬升量分别为1261 m/Ma、2634 m和388 m/Ma、1043 m;甘孜地区构造隆升具有不平衡性、阶段性、地区性差异,冷却速率、抬升速率和抬升幅度也存在偏差。

Based on fission track analysis of seven samples from Garze area on the eastern margin of the Tibetan Plateau, the authors obtained the apparent ages of the analyzed samples. Using the simulated annealing method, the authors made thermal history simulation for all samples, and obtained the thermal evolution history of these samples. According to the results obtained, the Garze area has experienced similar tectonic evolutions since Palaeogene, and the tectonic uplift occurred in 46-30 Ma and since 9 Ma of Neogene, with the uplift rate and average uplift amount being 1261 m/Ma, 2634 m and 388 m/Ma, 1043 m respectively. The tectonic uplifts in the Garze area are characterized by imbalance as well as stage and regional differences; in addition, there also exist deviations in cooling rate, uplift rate and uplift amplitude.