青藏高原面地貌稳定态与高原隆升时间  

Geomorphological Steady State of the Tibet Plateau and Its Uplift Time

作　　者：张信宝[1] 刘维明[1] 陈宁生[1,2] 代彬 ZHANG Xinbao;LIU Weiming;CHEN Ningsheng;DAI Bin(Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;Puding Karst Ecosystem National Observation and Research Station National Ecosystem Research Network of China,Puding 562100,Guizhou,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所,成都610041 [2]中国科学院大学,北京100049 [3]贵州普定喀斯特生态系统国家野外科学观测研究站,贵州普定562100

出　　处：《山地学报》2023年第4期459-468,共10页Mountain Research

基　　金：国家自然科学基金川藏铁路重大基础科学问题专项(41941017);国家自然科学基金面上项目(42071017)。

摘　　要：本文基于地貌垂直地带性理论,提出计算高原隆升时间的地貌演化模型,并利用GPS现代垂直位移速率资料,计算青藏高原高原隆升时间。海拔4000~5000 m的青藏高原高原面为冰缘地貌带,以上为冰川地貌带,以下为流水地貌带。青藏高原面的构造隆升速率难以超过砂板岩等软弱岩层的冻融侵蚀剥夷速率,处于地貌稳定态,高程受冰缘气候控制,与隆升速率无关。花岗岩、石灰岩等坚硬岩层组成的冰川山地,抗寒冻风化能力强,剥蚀和隆升的竞争中,隆升战胜剥蚀,处于地貌不稳定态,山地持续上升。根据珠峰高程、剥蚀岩层厚度,高原面高程和隆升速率,利用模型求得从青藏高原隆升到现今冰缘地貌带高程以来的隆升时间为2.5 Ma~7.8 Ma。Based on the theory of vertical zonality in geomorphology,this study introduced a geomorphic evolution model to calculate the uplifting time of the Tibet Plateau,which then was justified by the calculation obtained by GPS modern vertical displacement data.The plateau surface of the Tibet Plateau at an altitude of 4000-5000 m is a periglacial geomorphic zone,with glacial geomorphic zone above it and flowing water geomorphic zone below it.The tectonic uplift rate of the Plateau is not expected to exceed the rate of freeze-thaw erosion and stripping of weak rock layers such as sandstone slate;the Plateau surface is in a geomorphological steady state;the Plateau elevation is controlled by periglacial climate and has nothing to do with uplift rate.Glacial mountains above the Plateau ground composed of hard rock formations,such as granite and limestone,have strong resistance to frost weathering;the Plateau uplift overcomes frost denudation,leading to an unstable geomorphological state,with a steady rising in Plateau elevation.According to the peak elevation of Mount Qomolangma,the thickness of denuded rock layer,the elevation of the Plateau surface and the average rate of uplift measured by GPS in the Himalaya regions,by our model we estimate that the uplift time for the Qinghai-Tibet Plateau from the start of uplift to the elevation of the present-day periglacial geomorphic zone is 2.5-7.8 Ma.

关 键 词：地貌垂直地带性 地貌演化模型 GPS隆升时间 青藏高原 

分 类 号：P931.2[天文地球—自然地理学]