青海湖东岸沙地风成沉积物粒度敏感组分及其古气候意义

发布时间：2019-02-13 06:20

【摘要】：粒级-标准偏差的计算可用来提取沉积序列的粒度敏感组分。采用线性粒级和对数粒级两种粒度划分方法 ,对青海湖东岸沙地多个风成砂-古土壤沉积剖面进行了系统分析。结果表明:粒级划分对于敏感组分提取结果具有一定的影响,对数粒级提取的粗粒敏感组分比细粒组分具有更大标准偏差,而线性粒级的提取结果则显示细粒组分对于环境变化更为敏感;两种方法提取的细粒敏感组分差异较大,而较粗组分和粗粒组分较为一致。在运用粒级-标准偏差法提取环境敏感粒度指标时,两种划分方法都能有效地提取粗粒敏感组分,而在提取细粒敏感组分方面线性粒级较对数粒级划分法能取得更好的效果。采用线性粒级-标准偏差法提取了青海湖东岸沙地风成沉积物粒度敏感组分,发现黏粒组分(0~4μm)可以作为夏季风强度变化的替代性指标,中细砂组分(144~321μm)可以指示风沙活动的强弱,极细砂组分(60~126μm)可能受局部地形的影响较大,其古气候意义有待进一步查明。
[Abstract]:The calculation of grain-level standard deviation can be used to extract granularity sensitive components of sedimentary sequences. Based on linear granularity and logarithmic grain-grained methods, a systematic analysis of several aeolian sand paleosol sediment profiles in sandy land on the east coast of Qinghai Lake was carried out. The results showed that grain-level partition had a certain effect on the extraction results of sensitive components, and that the sensitive components extracted at logarithmic grain-level had greater standard deviation than fine-grained components. The linear grain-level extraction results showed that the fine-grained components were more sensitive to environmental changes. The sensitive components of fine grains extracted by the two methods were different from each other, but the coarser and coarse-grained components were the same. In the extraction of environmental sensitive granularity index by grain-level standard deviation method, both methods can extract sensitive components of coarse grains effectively, and the linear particle level is better than the logarithmic grain-level partition method in the extraction of sensitive components of fine grains. A linear grain-standard deviation method was used to extract the granularity sensitive components of eolian sediments from sandy land on the east coast of Qinghai Lake. It was found that the clay fraction (0 ~ 4 渭 m) could be used as an alternative index for the change of summer monsoon intensity. The medium and fine sand component (144 ~ 321 渭 m) can indicate the intensity of the aeolian sand activity, and the extremely fine sand component (60 ~ 126 渭 m) may be affected by the local topography, and its paleoclimatic significance needs to be further investigated.
【作者单位】：北京师范大学地表过程与资源生态国家重点实验室/防沙治沙教育部工程研究中心/地理科学学部;
【基金】：国家自然科学基金项目(41571184,41171159) 国家重点基础研究发展计划项目(2013CB956001)
【分类号】：P512.2;P532

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