干旱区生态环境知识资源中心(Arid): ~(10)Be和~(26)Al揭示的合黎山西南部侵蚀速率初步研究

Arid

	~(10)Be和~(26)Al揭示的合黎山西南部侵蚀速率初步研究
其他题名	Erosion rate in the southwest of Helishan from in-situ cosmogenic nuclides ~(10)Be and ~(26)Al
	张丽; 武振坤; 李明; 董国成; 赵国庆; 付云翀
来源期刊	地球环境学报
ISSN	1674-9901
出版年	2018
卷号	9 期号:1 页码:45-53
中文摘要	地表侵蚀速率是衡量地貌演化的一个重要因子。本研究利用原地宇宙成因核素~(16)Be和~(26)Al对合黎山西南部地表岩石侵蚀速率进行了首次测定。结果显示:约30 ka以来,合黎山西南部的地表岩石侵蚀速率约为24 mm·ka~(-1)。这一结果与已见报道的其他基岩侵蚀速率值一致。这一结果与Small et al获得的非干旱地区的基岩侵蚀速率也基本一致,但是显著高于干旱的南极地区和半干旱的澳大利亚。~(10)Be和~(26)Al获得的侵蚀速率的良好一致性表明本研究中所用侵蚀模式的有效性。所得的侵蚀速率小于Palumbo et al测定的合黎山平均流域侵蚀速率(99mm·ka~(-1)),原因解释尚待更多地点和样品的研究。
英文摘要	Background, aim,and scope Surface erosion rate is an important subject in evaluating geomorphic evolution of landforms. Our understanding of landform evolution, however, is limited by the lack of the data about landscape change rate in appropriate geological time scale. The accelerator mass spectrometry (AMS) -based cosmogenic nuclide technique is an increasingly utilized method that can measure long-term (>103_104 years) average erosion rates. Determination of in-situ ~(10)Be and ~(26)Al; in bedrock surfaces on summit flats constrains erosion rate for mountain ranges within various climatic environments. Studies on ~(10)Be environmental tracer and exposure dating/erosion rate have lagged behind in China due to lack of AMS facilities for routine ~(10)Be measurements. Based on the ~(10)Be and ~(26)Al samples preparation method in our laboratory, the article presents the erosion rate determined from ~(10)Be and ~(26)Al in quartz samples measured by AMS from outcrop bedrock collected from southwest Helishan, at the northeast margin of Tibetan Plateau. We hope to understand the effects of climate and tectonics on erosion rate better and especially to provide hints on the cause of the abrupt increase of erosion rates in northeast Tibet. Materials and methods Four rock samples were collected from the outcrop. The rocks were brought into the lab, be cleaned, dry, crush, and sieved. The 0.25 0.50 mm grain size were selected. The magnetic minerals were removed with magnetic separation. Pure quartz samples were completely dissolved with 0.3 0.5 mg 9Be carrier in hydrofluoric acid. Fluorides were removed by perchloric acid fuming. Beryllium and aluminum were separated by cation and anion exchange chromatography, and leached with 1 mol · L~(-1) HCl and an H_2C_2O_4-HCl acid mixture. Ammonium hydroxide was added to the ~(10)Be and ~(26)Al fractions to precipitate beryllium and aluminum hydroxide gels at pH = 89 and pH8,respectively, and the hydroxides were oxidized by ignition at 900℃ in quartz crucibles. The beryllium oxide and aluminum oxide products were mixed with copper powder and pressed into target holders prior to measurement on the AMS. Results The ~(10)Be/~9Be ratios of the samples were normalized to the NIST AMS standard SRM-4325 with a nominal value of ~(10)Be/~9Be = 2.6810~(-11)· The ~(26)Al/~(27)Al ratios of the samples were normalized to the ICN AMS standard with a nominal value of ~(26)Al/~(27)Al = 1.065 10~(-11). We calculate the ~(10)Be and ~(26)Al concentrations in quartz samples, combined the ~(10)Be/~9Be, ~(26)Al/~(27)Al ratio determined by AMS, with the sample weight, 9Be carrier weight and ~(27)Al weight. The erosion rates are determined by the CRONUS-Earth online calculator version 2.2. The minimum exposure ages are also shown. The maximum steady erosion rates of HLS-1-4 are (23.41.8) mm·ka~(-1) (Be) and (24.42.0) mm·ka~(-1) (Al). The maximum steady erosion rates of HLS-1-3 are well agreement with that of HLS-1-4,(33.412.9)mm·ka~(-1) (Be) and (24.21.9) mm·ka~(-1) (Al), respectfully. While A two-isotope plot of ~(10)Be and ~(26)Al data shows that samples HLS-1-4 and HLS-1-3 are consistent with a model of constant exposure. HLS-4-2 may have complex exposure histories, suggesting burial and re-exposure. The determined erosion rate of 24 mm·ka~(-1) is comparable with the erosion rates in other mountainous regions. Discussion Both tectonics and climate affect erosion of landforms.
中文关键词	宇宙成因核素~(10)Be和~(26)Al ; 合黎山西南部 ; 侵蚀速率
英文关键词	in-situ cosmogenic nuclides southwest of Helishan erosion rate
类型	Article
语种	中文
收录类别	CSCD
WOS类目	Geology
CSCD记录号	CSCD:6196472
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/378932
作者单位	张丽, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.; 武振坤, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.; 李明, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.; 董国成, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.; 赵国庆, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.; 付云翀, 中国科学院地球环境研究所;;西安加速器质谱中心, 黄土与第四纪地质国家重点实验室;;陕西省加速器质谱技术及应用重点实验室;;, 西安;;西安, ;; 710061;;710061.
推荐引用方式 GB/T 7714	张丽,武振坤,李明,等. ~(10)Be和~(26)Al揭示的合黎山西南部侵蚀速率初步研究[J],2018,9(1):45-53.
APA	张丽,武振坤,李明,董国成,赵国庆,&付云翀.(2018).~(10)Be和~(26)Al揭示的合黎山西南部侵蚀速率初步研究.地球环境学报,9(1),45-53.
MLA	张丽,et al."~(10)Be和~(26)Al揭示的合黎山西南部侵蚀速率初步研究".地球环境学报 9.1(2018):45-53.