新疆博格达—哈尔里克山白垩纪以来剥露历史的裂变径迹证据

Fission-track Evidence for the Exhumation History of Bogda—Harlik Mountains,Xinjiang Since the Cretaceous

对新疆博格达-哈尔里克山火山岩和花岗岩的15个磷灰石样品和5个锆石样品的裂变径迹年龄测定表明，磷灰石的裂变径迹年龄变化于109．3～11．9Ma之间，锆石的裂变径迹年龄变化于81．7～56．8Ma之间。矿物对法计算得到，该地区晚白垩世至新生代中期的视剥露速率为0．157～0．222mm／a。热史模拟结果表明，博格达一哈尔里克山自白垩纪以来经历了多期冷却剥露，分别是早白垩世（119～105Ma）、晚白垩世晚期（67～65Ma）、新生代早中期（47～31Ma）和新生代晚期（12～7Ma）。白垩纪以：来的天山变形作用，与亚洲南缘多期的地体碰撞增生有关。

Fifteen apatite samples and five zircon samples from volcanic rocks and granites in Bogda-Harlik mountains were analysed. The apatite ages range from 109.3 to 11.9Ma and the zircon ages are within the range 81. 7-56.8 Ma. Results of calculation by paired-minerals indicate that the apparent exhumation rates range from 0. 157 mm/a to 0. 222 mm/a during the Late Cretaceous to Middle Cenozoic in above area. The thermal history modeled result shows four periods of exhumation in Bogda--Harlik mountains occurred in Early Cretaceous （119 105 Ma） ,late Late Cretaceous （67--65 Ma）,Early-Middle Cxmozoic （47-31 Ma） and Late Cenozoic （12-7 Ma） since Cretaceous. The deformation in Tianshan regions since Cretaceous is related to the multi-stage collisions and accretions of terranes with the south Asian continental margin.