晚新生代以来青藏高原东缘的剥蚀过程:来自裂变径迹的证据  

The denudation of the eastern margin of the Qinghai-Xizang Plateau since the Late Cenozoic: Evidence from the fission-track ages

作　　者：张毅[1] 李勇[1] 周荣军[2] A.L.Densmore N.J.Richardson 

机构地区：[1]成都理工大学油气藏及开发工程国家重点实验室,四川成都610059 [2]四川省地震局工程地震研究所,四川成都610041 [3]Institute of Geology,Department of Earth Sciences

出　　处：《沉积与特提斯地质》2006年第1期97-102,共6页Sedimentary Geology and Tethyan Geology

基　　金：国家自然科学基金项目(40372084);四川省重点学科建设项目(SZD0408)

摘　　要：本文以青藏高原东缘的三级地貌(川西高原、龙门山和四川盆地)单元为基础,利用裂变径迹定年数据分区块研究了该地区的晚新生代以来的剥蚀速率。研究结果表明,晚白垩世以来青藏高原东缘经历了一个由平缓到突然加速的剥蚀过程,其转折点为中新世。在整个时间段内的平均剥蚀速率,川西高原为0.26mm/yr,龙门山为0.72mm/yr,四川盆地为0.20mm/yr。龙门山的剥蚀速率大约是川西高原的2.8倍,间接反映边缘山脉的隆升并不等同于高原内部的隆升,边缘山脉的隆升可能是构造隆升和剥蚀隆升相叠加的结果。The denudation rates of the eastern margin of the Qinghai-Xizang Plateau since the Late Cenozoic are examined for the third-order geomorphological units （western Sichuan plateau, Longraen Mountains and Sichuan Basin） on the basis of the fission-track ages for the samples from different blocks in the study area. The findings show that there are gradations of denudation from slow processes before the Miocene to rapid ones after the Miocene. The mean denudation rate is 0.26 mm/yr for the western Sichuan plateau, 0.72 mm/yr for the Longmen Mountains, and 0.20 mm/yr for the Sichuan Basin. It can be seen that the mean denudation rate for the Longmen Mountains is about 2.8 times than that for the western Sichuan plateau, implying that the uplift of the marginal mountain ranges does not means that of the Plateaul the former may be combination of tectonic uplift and denudational uplift.

关 键 词：青藏高原东缘 晚新生代 裂变径迹 剥蚀速率 隆升 

分 类 号：P631.621[天文地球—地质矿产勘探]