文章摘要
黄费新.原地生成宇宙成因核素测年技术思考(三): 暴露、侵蚀、埋藏、再暴露和地表升降过程的双核素投影[J].地质与勘探,2019,55(6):1500-1509
原地生成宇宙成因核素测年技术思考(三): 暴露、侵蚀、埋藏、再暴露和地表升降过程的双核素投影
Consideration on in situ produced cosmogenic nuclide dating techniques (3): Dual-nuclides projection of exposure, erosion, burial, re-exposure, and surface uplift and subsidence
投稿时间:2019-03-11  修订日期:2019-06-20
DOI:10.12134/j.dzykt.2019.06.016
中文关键词: 抬升 下降 原地生成宇宙成因核素 浓度比值投影 稳态侵蚀岛
英文关键词: uplift, subsidence, in situ produced cosmogenic nuclide, concentration ratio projection, steady state erosion island
基金项目:国家自然科学基金面上项目(编号:41873064)和面上项目(编号:41176166)联合资助。
作者单位E-mail
黄费新 中国冶金地质总局矿产资源研究院北京 南京大学地球科学与工程学院江苏南京 中国科学院地球环境研究所陕西西安 西安加速质谱中心陕西西安 chengyang1104@126.com 
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中文摘要:
      双核素稳态侵蚀岛投影是原地生成宇宙成因核素测年技术中判断样品是否具有复杂暴露历史和估计侵蚀速率的常用方法。暴露、侵蚀、埋藏、再暴露的投影图可依据传统核素浓度计算等式利用计算机编程绘出。利用新推出的地表持续抬升与下降过程中样品的核素浓度与生成速率(及加速率)、侵蚀速率及暴露时间的计算等式,对其26Al/10Be浓度比值相对于10Be浓度/10Be生成速率投影分别进行了计算机模拟,发现下降样品的投影可右偏于稳态侵蚀岛,而抬升样品的投影仍然在稳态侵蚀岛内。利用持续地表下降,可以解释已往文献数据中一次性暴露样品投影右偏于稳态侵蚀岛的“不合理”现象,而持续抬升对投影结果的影响类似于侵蚀,因此如果忽略抬升,计算的暴露年龄结果将偏小。
英文摘要:
      Dual-nuclide steady state erosion island projection is a common method to determine whether samples have complex exposure history (burial), and to estimate the erosion rate in the in situ produced cosmogenic nuclide dating. Projections of exposure, erosion, burial, and re-exposure can be plotted by computer programming according to traditional nuclide concentration and produce rate formulas. Using the new formula of the surface uplift and subsidence, the 26Al/10Be concentration ratio relative to the concentration of 10Be projection is simulated by computer. Results show that the projection of the subsidence sample is higher than or right to the erosion island, while the projection of uplift is still in the steady erosion. Therefore, continuous surface subsidence can explain the "unreasonable" phenomenon that samples with single exposure history will be projected on higher than or right to the steady state erosion island as reported in previous work. Meanwhile the effect of continual uplift on the projection is similar to erosion, so if ignoring the uplift, the exposure age calculated will be smaller.
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