Abstract:

The sediments in an orogen contain very rich tectonic information The Jiuxi basin, located in the triangular belt between Altyn Tagh Fault(ATF) and North Qilian Fault(NQF), was affected by strong active tectonics in the early Cenozoic; therefore, it was covered by mass sediments which could reflect the tectonic actions and uplift process nearby The assemblage, texture and sensitive index (ATi, GZi and ZTR) of the sedimental heavy minerals show regular variations in the Huoshaogou and Hongliuxia sections of Jiuxi basin in 4030 Ma The detailed study of the heavy mineral has revealed four different stages: ①the unstable mineral stage (Shanmacheng segment, 402379 Ma); ②the stable mineral stage (Qiaojia segment, 379353 Ma); ③the unstable mineral stage (Hongliuxia segment, 353334 Ma); ④the extra unstable mineral stage (Baiyanghe Formation, 33430 Ma) In addition, the detailed analysis of heavy mineral characteristics and sedimentary characteristics shows that there should be four different tectonic stages in the Jiuxi basin between 40 and 30 Ma: ①the strong tectonic stage (402379 Ma); ②the stable tectonic stage (379353 Ma); ③the thrusting and striking stage (353334 Ma); ④the strong thrusting stage (33430 Ma)

Key words:

Key words: Jiuxi basin; heavy mineral; ATi; GZi; ZTR