摘要
This paper applies fission track thermochronology to probe mineralization age for six gold deposits and reveal the evolution of geological thermal history and tectonic events in the last 200Ma in Ganzi-Litang gold belt, Tibet Plateau. The results of zircon fission track analysis suggest the main mineralization ages are about 82~140Ma, decreasing from south section to north section. The mineralization ages are 124~140Ma, 107Ma and 82Ma in the south section, the middle section and the north section respectively. The apatite fission track analysis shows the similar trend from south section to north section, in which the ore ages are about 14~27Ma and the wallrock ages are 88~95Ma. Thermal history modeling results show that three cooling stages since Yanshannian. The first stage occurred before 200~140Ma and the third stage after 30Ma. The cooling rates were fast from south section to north section. From zircon closure temperature 250℃ to apatite closure temperature 100℃, the three ages had different cooling rates of 1.46℃/Ma, 1.67℃/Ma and 2.21℃/Ma, and uplifting rates were 48.7m/Ma, 55.7m/Ma and 73.7m/Ma respectively. From 100℃ to surface temperature, the three stages have average cooling rates of 3.15℃/Ma, 5℃/Ma and 6.07℃/Ma, and uplifting rates of 104.9m/Ma, 166.7m/Ma and 202.4m/Ma respectively. Thermal history modeling results reveal that uplifting rates were very fast in the last 3Ma. The cooling rate, uplifting rate and uplifting amount averaged 20℃/Ma, 667m/Ma, and 2km, indicating rapid uplifting.