周家兴, 于娟, 杨丽君, 吴利杰. 铜川地区早中全新世黄土沉积特征及其古气候意义[J]. 海洋地质与第四纪地质, 2020, 40(1): 160-166. DOI: 10.16562/j.cnki.0256-1492.2018091901
引用本文: 周家兴, 于娟, 杨丽君, 吴利杰. 铜川地区早中全新世黄土沉积特征及其古气候意义[J]. 海洋地质与第四纪地质, 2020, 40(1): 160-166. DOI: 10.16562/j.cnki.0256-1492.2018091901
ZHOU Jiaxing, YU Juan, YANG Lijun, WU Lijie. Sedimentary characteristics of the Early and Middle Holocene loess in Tongchuan area and their implications for paleoclimate[J]. Marine Geology & Quaternary Geology, 2020, 40(1): 160-166. DOI: 10.16562/j.cnki.0256-1492.2018091901
Citation: ZHOU Jiaxing, YU Juan, YANG Lijun, WU Lijie. Sedimentary characteristics of the Early and Middle Holocene loess in Tongchuan area and their implications for paleoclimate[J]. Marine Geology & Quaternary Geology, 2020, 40(1): 160-166. DOI: 10.16562/j.cnki.0256-1492.2018091901

铜川地区早中全新世黄土沉积特征及其古气候意义

Sedimentary characteristics of the Early and Middle Holocene loess in Tongchuan area and their implications for paleoclimate

  • 摘要: 通过对铜川剖面黄土-古土壤沉积粒度的组成和变化特征及磁化率值进行分析,探讨了该地区11.4~1.5 kaBP期间的古气候变化特征。结果表明:(1)铜川剖面黄土-古土壤沉积以粉砂粒(4~63 μm)为主,黏粒(<4 μm)次之,砂粒(>63 μm)含量最低。(2)粒度和磁化率值在不同地层单元呈规律性变化:粉砂粒和砂粒在黄土层中较高,古土壤层中较低;黏粒和磁化率值在黄土层中较低,古土壤层中较高。(3)粉砂粒、黏粒和磁化率值的变化情况较好地记录了铜川地区11.4~1.5 kaBP期间的气候变化特征,可以将该地区的气候变化划分为4个阶段:11.4~10.2 kaBP寒冷干燥期,10.2~9.1 kaBP略温偏干期,9.1~4.4 kaBP温暖湿润期,4.4~1.5 kaBP较冷干期。

     

    Abstract: The grain size of the loess and palaeosol in the Tongchuan section was studied as the main subject of this paper. Combining the magnetic susceptibility data, we analyzed the paleoclimate changes during the period from 11.4 to 1.5 kaBP. It is revealed that: (1) The loess-palaeosol deposits in the profile of Tongchuan are silt dominated (69.78%) over clay (28.35%) and sand (1.87%). (2) Silt and sand are higher in loess but lower in paleosol, while the values of clay particles and magnetization were lower in loess but higher in paleosol layers. (3) The variation trend of the clay (<4 μm), silt (4~63 μm) and magnetic susceptibility index have good correspondence to the loess-palaeosol alternation and the cold and dry climatic events between 11.4~1.5 kaBP. Based upon it the climate change in this area can be divided into four stages. In the period of 11.4~10.2 kaBP, the climate was very dry and cold; in the period of 10.2~9.1 kaBP, temperature gradually increased, and the climate was slightly warm and dry; during the period of 9.1~4.4 kaBP, the climate was warm and humid; while in the period of 4.4~1.5 kaBP, climate gradually turned to cold and dry.

     

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