喜马拉雅山脉新生代差异隆升的裂变径迹热年代学证据_刘超

第14卷第6期2007年11月

地学前缘(中国地质大学(北京);北京大学)

Earth Science Frontiers (Chin a University of Geosciences,Beijing;Peking University)Vol.14No.6Nov.2007

收稿日期:2007-06-20;修回日期:2007-07-17

基金项目:中国地质调查局重大基础研究项目/青藏高原新生代地质作用过程与第四纪环境演变综合研究0(1212010610103)作者简介:刘 超(1983)),男,硕士研究生,构造地质学专业,从事构造年代学学习和研究。

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通信作者:w gcan@cug 1edu 1cn

喜马拉雅山脉新生代差异隆升的裂变径迹热年代学证据

刘 超

1,2

, 王国灿

1,2*

, 王 岸

1,2

, 王 鹏

1,2

任春玲

3

11地质过程与矿产资源国家重点实验室,湖北武汉43007421中国地质大学(武汉)地球科学学院,湖北武汉43007431中国石油华北油田勘探开发研究院,河北任丘062552

Liu Chao 1,2, Wang Guocan *

1,2

, W ang An 1,2, Wang Peng 1,2 Ren Chunling 3

11S tate K ey L abor atory of G eological Pr oce sse s and M iner al Re souce s,China Univ ersity of G eosc ienc e ,W uhan 430074,China 21F aculty of Ear th S cie nce ,Ch ina Univ e rsity of Ge oscience ,Wu han 430074,China

31Oil E xp lor ation and De ve lop ment I nstitute ,CN PC H u abei Oil f ield Comp any ,R enqiu 062552,China

Liu Chao,Wang Guocan,Wang An,et al 1Fission -track evidence of Cenozoic diff erent uplift processes of Himalayan Mountains.Earth Science Frontiers ,2007,14(6):273-281

Abstract:Coo ling ag es of the H imala yan M ount ains,south of Y arlung Zangbo R iver ,r eco rded by fission -tracks sho w remarkably spatial and tempo ral differ ences.In the no rth -south dir ect ion,fissio n -track ages of T ethys H imalay an belt sugg est that cooling occurr ed mainly befor e 8M a,partially betw een 5.0-2.6M a,but in the H ig her H imalayan belt coo ling mainly since 5M a,mo st ly since 3M a.In the east -w est direction,spatia l differences ar e embodied in t he H igher H imalayan belt.F ission -tr ack thermochro no lo gy show ed that co oling and denudation occur red betw een 8.0-3.0M a in t he Easter n Himalay as of centra l and eastern Bhutan,and cooling o ccur red between 7.0-1.4M a in w estern Bhutan.In the central H imalayas (Nepal )cooling occurr ed betw een 5.0-0.2M a,and coo ling ag es distr ibute bet ween 3.0- 1.0M a in the w ester n H imalayas.T he yo ungest fission track ages sho w an increasing trend fr om middle to bo th eastern and w ester n sides,reflect ing a denudatio n rate hav ing beco me larg er f rom centr e to war ds the east and west of the H igher H imalayan belt be -tween Easter n and Western H imalay an Sy nt axes in t he v ery recently g eolog ical t ime.A systematic inv est iga -tion of published fissio n -t rack ages sug gests that t he denudat ion of the H imalayas occurred since the M iocene,exhibit ing tw o uplifting stages:at 18-11M a and fr om 9M a onwa rds.T he investigation also sho ws that the mechanism of the H imalayan uplift may hav e chang ed fro m an ea rlier compressional uplift to a later ex tensio na l uplift in the M io cene,caused by tectonic fo rces and co upled w ith t he effects o f lo cal climate in the Late M io -cene.

Key words:fission -tr ack;Himalayan mountains;coo ling ages;denudation;Cenozoic

摘 要:裂变径迹年龄资料记录的雅鲁藏布江以南的喜马拉雅山脉的冷却年龄具有明显的时空差异性。在南北方向上,特提斯喜马拉雅的冷却年龄主要在8M a 以前,局部为510~216M a,而高喜马拉雅的冷却年龄集中在5M a 以后,大多数在3M a 以来;在东西方向上体现在喜马拉雅东西构造结之间的高喜马拉雅带上,东