中国沙漠 ›› 2020, Vol. 40 ›› Issue (1): 64-76.DOI: 10.7522/j.issn.1000-694X.2019.00046

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杜慧荣1, 谢远云1,2, 康春国2, 迟云平1,2, 王嘉新1, 孙磊1   

  1. 1. 哈尔滨师范大学 地理科学学院 黑龙江 哈尔滨 150025;
    2. 哈尔滨师范大学 寒区地理环境监测与空间信息服务黑龙江省重点实验室, 黑龙江 哈尔滨 150025;
    3. 哈尔滨学院 地理与旅游学院, 黑龙江 哈尔滨 150086
  • 收稿日期:2019-02-15 修回日期:2019-04-15 出版日期:2020-01-20 发布日期:2020-01-18
  • 通讯作者: 谢远云,
  • 作者简介:杜慧荣(1995-),女,黑龙江伊春人,硕士研究生,主要从事亚洲风尘系统物源示踪研究。
  • 基金资助:

Grain-size and geochemical compositions of the Harbin loess deposits and their implications for eolian dust provenances

Du Huirong1, Xie Yuanyun1,2, Kang Chunguo2, Chi Yunping1,2, Wang Jiaxin1, Sun Lei1   

  1. 1. College of Geographic Science Harbin Normal University, Harbin 150025, China;
    2. Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, China;
    3. School of Geography and Tourism, Harbin University, Harbin 150086, China
  • Received:2019-02-15 Revised:2019-04-15 Online:2020-01-20 Published:2020-01-18

摘要: 哈尔滨黄土位于欧亚黄土带的最东端,对它的风尘物源研究是深层次理解风尘堆积与区域构造-地貌-气候变化耦合关系的关键。然而,对哈尔滨黄土地球化学组成的研究尚未开展,对其性质还存在认识上的不统一。为此,我们研究了哈尔滨天恒山剖面L1黄土层的粒度和地球化学组成,并对其化学风化和物源等展开讨论。为了示踪哈尔滨黄土的物源,我们还对东北沙地(浑善达克沙地、科尔沁沙地、呼伦贝尔沙地和松嫩沙地)进行了表土采样和地球化学分析。结果表明:哈尔滨黄土不含细砂组分(125~250 μm),含有极细砂组分(63~125 μm,4.8%~10.5%),粉砂(4~63 μm)和黏土组分(<4 μm)占绝对优势,分别占73%~82%和12%~18%;粒度模式为三峰态分布(众数分别为36~40、8~10 μm和0.8 μm),与黄土高原典型黄土的粒度分布模式一致,但明显粗于黄土高原中部黄土。哈尔滨黄土经历了初级的化学风化过程,具有较低的成熟度和再循环历史。单靠地球化学方法不能很好地确定哈尔滨黄土的物源,但整合的方法(包括粒度、元素和同位素组成、MDS和PCA统计方法以及自然地理要素等)很好确定了哈尔滨黄土有一个混合源,松嫩沙地松花江水系沉积物为哈尔滨黄土提供了主要的粉尘贡献,浑善达克沙地和科尔沁沙地为哈尔滨黄土提供了部分细颗粒粉尘。

关键词: 物源, 哈尔滨黄土, 地球化学, 粒度, 松嫩沙地

Abstract: The Harbin loess deposits are located at the easternmost edge of the Eurasian loess belt. The study of eolian dust material origin for the Harbin loess deposits is the key to better understanding the relationship between dust accumulation and regional structure, landform and climate change. However, the investigations for the geochemical composition of Harbin loess deposits have not yet been carried out. Therefore, the grain-size and geochemical compositions of L1 loess in the Harbin Tianhengshan section were analyzed, and chemical weathering, maturity and material sources for the Harbin loess were discussed. In order to trace the material source of the Harbin loess, surface sample collection and geochemical analysis were also carried out in the Northeast Sandy Land (including Hunshandake Sandy Land, Horqin Sandy Land, Hulun buir Sandy Land and Songnen Sandy Land). The results show that the Harbin loess does not contain fine sand components (125-250 μm), but contains moderate amount of extremely fine sand components (63-125 μm, 4.8%-10.5%). The silt (4-63 μm) and clay (<4 μm) components dominantly account for 73%-82% and 12%-18%, respectively. The particle-size pattern was trimodal with modes 36-40 μm, 8-10 μm and 0.8 μm, consistent with the grain size distribution pattern of typical loess in the Loess Plateau, but coarser than that of the loess in the middle Loess Plateau obviously. We showed CIA and W indices, A-CN-K and WMF triangle diagrams, SiO2/Al2O3 ratios and ICV values, and finally a binary diagram of K2O/Al2O3 and Na2O/Al2O3. They revealed that the Harbin Loess has undergone a simple chemical weathering process with a low maturity and recycling history. Combined with grain size, element geochemistry, Sr-Nd isotopic ratios and mathematical statistical methods of MDS and PCA, It is believed that the Harbin loess deposits are from proximal areas, and the Songnen Sandy Land provides the main dust material for the Harbin loess deposits, and that the Hunshandake Sand Land and the Horqin Sand Land may also provide a small amount of fine dust for the Harbin loess deposits and however, the Hulunbuir Sand Land cannot be the source of the Harbin loess deposits. The Harbin loess deposits were the product of dust storm weather in spring.

Key words: provenance, Harbin loess, geochemistry, grain size, Songnen Sandy Land