柴达木盆地昆特依盐湖磁化率特征及古气候意义
Magnetic Susceptibility of Kunteyi Salt Lake during the Late Quaternary and Its Paleoclimatic Significance
投稿时间:2015-10-13  修订日期:2015-11-19
DOI:
中文关键词:  柴达木盆地  昆特依盐湖  磁化率  古气候
英文关键词::Qaidam Basin  Kunteyi salt lake  Magnetic susceptibility  Paleoclimate
基金项目:中国地质调查局地质调查项目(12120113033029);中国科学院青海盐湖研究所青年引导基金(Y460261051)
作者单位E-mail
曾方明 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 fmzeng@163.com 
向树元 中国地质大学地球科学学院,湖北 武汉 430074  
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中文摘要:
      昆特依盐湖是柴达木盆地盐湖演化和古气候研究的重要对象。前人对昆特依盐湖钻孔的年代学和地球化学组成特征开展过一些研究,但由于采样间距大,限制了对成盐演化过程的深入理解。目前关于昆特依盐湖磁化率特征的研究尚未见报道。对昆特依盐湖ZK1402钻孔 35 m深 的14C年代和磁化率进行了初步研究。结果表明:1 钻孔由含盐碎屑层和盐层的互层所组成。盐层的低频磁化率值低,含盐碎屑层的低频磁化率值高。低频磁化率清晰地记录到古盐湖经历了4次显著的成盐期。钻孔的低频磁化率和高频磁化率的变化极为相似。2 低频磁化率和频率磁化率(百分比形式)呈负相关关系。3 钻孔9.6 m深处的加速器质谱 AMS14C校正年代为23 333±255 cal a BP,24.8 m深处的年代为31 780442 cal a BP,33.0 m深处的年代19 259207 cal a BP 出现倒转。钻孔24.8 m和33.0 m深处的14C年龄可能被低估。
英文摘要:
      :Kunteyi salt lake is of significance for studying evolution of salt lake in the Qaidam Basin.Some researches on geochronology and geochemistry have been investigated for drilling core from the Kunteyi salt lake.However, due to large intervals of samples, more details of paleoclimatic information recorded in the drilling core from the Kunteyi salt lake are not recorded by geochemical proxies.Moreover, magnetic susceptibility in the Kunteyi salt lake is not reported until now.Here, we present AMS accelerator mass spectrometry 14C ages and magnetic susceptibility in a 35 m depth core ZK1402 from Kunteyi salt lake.The results show that:1 The core is composed of salt layers and detrital layers. The value of low frequency magnetic susceptibility in salt layers is low, but it is high in detrital layers.Four periods of salt formation have been clearly implicated by variations of low frequency magnetic susceptibility.Variations of low frequency magnetic susceptibility and high frequency magnetic susceptibility are extremely similar.2 Low frequency magnetic susceptibility and frequency-dependent magnetic susceptibility in percentage are negatively correlated.3 The calibrated AMS14C ages at the depth of 9.6 m and 24.8 m in the ZK1402 core are 23 333±255cal a BP and 31 780442cal a BP,respectively.However, the AMS14C age at the depth of 33.0 m is reversed, with an age of 19 259207cal a BP.14C ages at the depth of 24.8 m and 33.0 m are probably underestimated.
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