柴达木盆地碱山深钻的硼同位素地球化学特征
Boron Isotope Geochemistry of Janshan Deep Borehole in Qaidam Basin 
投稿时间:2019-01-20  修订日期:2019-03-04
DOI:10.12119/j.yhyj.202001008
中文关键词:  柴达木盆地  硼同位素  碱山背斜  气候干旱化  盐度  晚中新世
英文关键词:Qaidam Basin  Boron isotope  the Jianshan Anticline  Climate drought  Salinity  Late Miocene
基金项目:国家自然科学基金面上项目(41571200);青年基金项目(41301222)
作者单位E-mail
卢胜城 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008
青海省盐湖地质与环境重点实验室, 青海西宁 810008
中国科学院大学,北京 100049 
lushengcheng16@mails.ucas.ac.cn 
韩文霞 临沂大学资源环境学院,山东省水土保持与环境保育重点实验室,山东临沂 276005  
韩凤清 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008
青海省盐湖地质与环境重点实验室, 青海西宁 810008 
 
马云麒 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008  
吕爽 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008
青海省盐湖地质与环境重点实验室, 青海西宁 810008
中国科学院大学,北京 100049 
 
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中文摘要:
      沉积物硼(B)同位素组成可以反映其地质成因及经历的地质过程,因此在许多领域的研究中都有较为广泛的应用。通过对位于柴达木盆地碱山背斜顶部的SG-1b钻孔沉积物(7.3~1.6 Ma)水溶组分的B同位素研究,发现钻孔沉积物B含量在38.55~172.3 μg/g之间,平均含量为87.6 μg/g;δ11B值的变化范围在3.61‰~16.26‰之间,平均值为10.65‰,B含量与δ11B值具有一定的正相关关系。进一步分析表明,受到碱山背斜构造隆升以及晚新生代以来气候干旱化的影响,柴西古湖逐渐咸化萎缩,沉积环境以及碳酸盐含量、粘土矿物含量及其矿物组合等也在发生变化,B含量和δ11B值自钻孔底部向上的逐步增加以及后期的急剧增加,与水溶离子含量以及矿物和粒度等的变化一致,这说明柴达木盆地晚中新世以来湖泊沉积物的B含量和δ11B值可以很好地反映研究区气候和湖水的演化过程,共同指示了研究区自7.3 Ma以来气候的持续干旱化和湖水盐度的逐步增加,以及3.3Ma以来干旱化和湖水浓缩过程的加剧。
英文摘要:
      Boron (B) isotopic composition of the sediments can reflect its geological genetic environment and geological process, so it has been widely used in many fields. In this paper, we studied the B isotopes of the water-soluble components from the SG-1b borehole sediments located at the top of the Jianshan Anticline in the western Qaidam Basin. The results show that the B contents range from 38.55 to 172.3 μg/g, with an average 87.6 μg/g; and the variation of the δ11B values is 3.61‰ to 16.26‰, with an average 10.65‰. There is a positive correlation between the B content and the δ11B value. Further analysis shows that, influenced by the uplift of the Jianshan anticline and the climate drought since the late Cenozoic, the paleolake in Qaidam Basin has gradually become salty and shrinking, and the sedimentary environment, carbonate content, clay mineral content and mineral assemblage have also changed.From the bottom of the borehole to the top, the gradual increase of B contents and δ11B values is consistent with the results of water soluble ion contents, mineral assemblages and particle size. It shows that the B content and δ11B value of lake sediments in Qaidam Basin since the Late Miocene can reflect the evolution process of climate and lake water in the study area, and the results indicate the continuous drought of climate and the gradual increase of salinity of lake water in the study area since 7.3 Ma, and the intensification of the process of drought and lake water salinization since 3.3 Ma.
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