The long-term denudation rate of granitic regolith in Qinhuangdao, North China determined from the in situ depth profile of the cosmogenic nuclides ^(26)Al and ^(10)Be  

作　　者：Lifeng Cui Congqiang Liu Sheng Xu Zhiqi Zhao Chenglong Tu Taoze Liu Hu Ding 

机构地区：[1]State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Scottish Universities Environmental Research Centre, Glasgow G75 0QF, UK

出　　处：《Chinese Science Bulletin》2014年第34期4823-4828,共6页

基　　金：supported by the National Natural Science Foundationof China(41130536,41210004);the State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences(9014)

摘　　要：This study quantifies the surface denudation rate of granitic regolith via the application of the in situ cosmogenic26 Al and10Be depth profile in China. The concentration ranges of26 Al and10Be in the quartz along the*3-m granitic regolith profile in Qinhuangdao are(4.9–23.1) 9 105and(2.3–36.6) 9 104atoms/g, respectively. With the exception of the surface sample, both26 Al and10Be concentrations decrease exponentially with sample depth. The Chi-square best-fitting results revealed a total denudation rate of *9 m/Ma averaged over a 103–105a timescale, which is lower than the values observed in global granitic outcrops. Compared with global datasets, the flat terrain due to the lack of tectonic activities is most likely the dominant factor that controls the local denudation process.The surface sample offsets from the theoretical cosmogenic nuclide distribution implies that the denudation rate from river basin sediment could be overestimated because of the bioturbation in the surficial soil layer.This study quantifies the surface denudation rate of granitic regolith via the application of the in situ cosmogenic ^26Al and ^10Be depth profile in China. The concentration ranges of ^26Al and ^10Be in the quartz along the -3-m granitic regolith profile in Qinhuangdao are （4.9-23.1） × 10^5 and （2.3-36.6）×10^4 atoms/g, respectively. With the exception of the surface sample, both ^26Al and ^10Be concentrations decrease exponentially with sample depth. The Chi-square best-fitting results revealed a total denudation rate of -9 m/Ma averaged over a 103-105 a timescale, which is lower than the values observed in global granitic outcrops. Compared with global datasets, the flat terrain due to the lack of tectonic activities is most likely the dominant factor that controls the local denudation process. The surface sample offsets from the theoretical cosmogenic nuclide distribution implies that the denudation rate from river basin sediment could be overestimated because of the bioturbation in the surficial soil layer.

关 键 词：宇宙成因核素 剥蚀速率 中国北方 花岗岩 风化层 秦皇岛 深度剖析 浓度范围 

分 类 号：P512.1[天文地球—地质学]