| 引用本文: | 昝金波,杨胜利,方小敏.2014.西昆仑山黄土1 Ma 以来的粒度变化特征及其古气候意义[J].地球环境学报,(2):120-126 |
| ZAN Jin-bo,YANG Sheng-li,FANG Xiao-min.2014.Grain size composition of West Kunlun Mountains loess in the past 1 Ma and its paleoclimatic implications[J].Journal of Earth Environment,(2):120-126 |
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| 摘要: |
| 塔里木盆地南缘保存有中国西北地区厚度最大的黄土，是详细研究亚洲内陆极端干旱
区以及塔克拉玛干沙漠形成演化的理想材料。但是，目前对该地区黄土堆积粒度特征系统的研
究还相对较少，对粒度指标的古环境意义仍存有不同的认识。通过对207 m 黄土岩芯的粒度分
析发现，西昆仑山黄土的粒度组成比较均一，分选较好，主要以粗颗粒物质为主，细颗粒含量
极少，并具有典型的风成成因特征。此外，西昆仑山黄土粒度1 Ma 以来呈现出持续变粗的趋势。
通过与其他气候指标的对比，这种变粗的趋势可能主要反映了中更新世以来亚洲内陆逐步增强
的干旱化过程。 |
| 关键词: 中亚内陆 西昆仑山 黄土 粒度 干旱化 |
| DOI：10.7515/JEE201402009 |
| CSTR： |
| 分类号:P532 |
基金项目:国家自然科学基金项目(41321061，41102101)；中国科学院战略性先导科技专项(XDB03020401)
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| Grain size composition of West Kunlun Mountains loess in the past 1 Ma and its paleoclimatic implications |
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ZAN Jin-bo1, YANG Sheng-li2, FANG Xiao-min1
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1. Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy
of Sciences, Beijing 100101, China;2. Research School of Arid Environment and Climate Change, Lanzhou University,
Lanzhou 730000, China
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| Abstract: |
| Hundreds of meters of loess were deposited on the northern slope of the Kunlun Mountains
area, which provide a great potential to reconstruct the aridification history of the interior Asia.
However, data regarding the grain size distribution of these loess deposits are relatively scarce, and
paleoenvironmental interpretations of grain size records remain controversial. For this study, detailed
bulk grain size studies were conducted for a 207-m-long loess core on the northern slope of the West
Kunlun Mountains. We find that the grain size of the loess core shows a much coarser fraction than that
on the central Loess Plateau as the deposition here is much closer to the desert source area. In addition,
the grain sizes of dusts collected at the drilling site show the same grain size composition as those of the
loess from the core, indicating an aeolian origin for the West Kunlun Mountains loess. The granulometry
demonstrates a long-term upward increasing trend over the past 1 Ma, which might be caused by a
persistent drying of Central Asia in the Mid-Pleistocene. |
| Key words: Central Asia West Kunlun Mountains loess grain size aridification |
