How does the elevation changing response to crustal thickening process in the central Tibetan Plateau since 120 Ma?  

作　　者：Zhong-bao Zhao Chao Li Xu-xuan Ma 

机构地区：[1]Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China

出　　处：《China Geology》2021年第1期32-43,共12页中国地质（英文）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0901);the Natural Science Foundation of China(41672211);the China Geological Survey(DD20190059);the Fundamental Research Funds for institute of geology,CAGS(JYYWF201810).

摘　　要：When and how the Tibetan Plateau formed and maintained its thick crust and high elevation on Earth is continuing debated.Specifically,the coupling relationship between crustal thickening and corresponding paleoelevation changing has not been well studied.The dominant factors in crustal thickness changing are crustal shortening,magmatic input and surface erosion rates.Crustal thickness change and corresponding paleoelevation variation with time were further linked by an isostatic equation in this study.Since 120 Ma crustal shortening,magmatic input and surface erosion rates data from the central Tibetan Plateau are took as input parameters.By using a one-dimensional isostasy model,the authors captured the first-order relationship between crustal thickening and historical elevation responses over the central Tibetan Plateau,including the Qiangtang and Lhasa terranes.Based on the modeling results,the authors primarily concluded that the Qiangtang terrane crust gradually thickened to ca.63 km at ca.40 Ma,mainly due to tectonic shortening and minor magmatic input combined with a slow erosion rate.However,the Lhasa terrane crust thickened by a combination of tectonic shortening,extensive magmatic input and probably Indian plate underthrusting,which thickened the Lhasa crust over 75 km since 25 Ma.Moreover,a longstanding elevation>4000 m was strongly coupled with a thickened crust since about 35 Ma in the central Tibetan Plateau.

关 键 词：Crustal thickness PALEOELEVATION Isostatic modeling Qiangtang terrane Lhasa terrane Tibetan Plateau China 

分 类 号：P542[天文地球—构造地质学]