汉江上游黄土常量元素地球化学特征及区域对比

发布时间：2018-03-28 20:31

本文选题：黄土　切入点：常量元素　出处：《地理学报》2017年02期

【摘要】：本文对汉江上游黄土的常量元素含量及相关地球化学参数CIA、Na/K、淋溶系数、退碱系数、残积系数等进行了系统分析。结果显示:1汉江黄土的主要化学成分为Si O2、Al2O3和Fe2O3,三者含量总和达767.3 g/kg;常量元素含量大小排序为Si O2Al2O3Fe2O3K2OMg ONa2OCa O。风化成壤过程中Na、Ca、Mg、Si发生不同程度的迁移淋溶,而Fe、Al、K相对富集。2其风化成壤强度呈现从马兰黄土L1→过渡性黄土Lt→古土壤S0逐渐升高、全新世黄土L0又降低的规律,记录了该区域气候经历了末次冰期(55.0-15.0 ka BP)冷干、早全新世(15.0-8.5 ka BP)增温增湿、中全新世(8.5-3.1 ka BP)达到最暖湿,晚全新世(3.1-0.0 ka BP)降温变干的演变过程。3汉江黄土与洛川、巫山、下蜀黄土的元素组合特征高度一致,不同地区常量元素(Ca O除外)含量十分接近且UCC标准化值变幅均小于0.25,这暗示了它们风化之初具有相似的风成沉积基础;但不同区域黄土的化学风化强度差异明显,大致呈现洛川黄土汉江黄土巫山黄土下蜀黄土的趋势,与中国现代季风气候的空间变化规律相吻合,即不同地区黄土风化程度差异主要是东亚季风变化影响的结果。
[Abstract]:In this paper, the constant element content and related geochemical parameters of loess in the upper reaches of the Hanjiang River, CIA-Na / K, leaching coefficient and desalination coefficient, are studied. The results show that the main chemical components of the loess are Sio _ 2 Al _ 2O _ 3 and Fe _ 2O _ 3, the sum of the three contents is 767.3 g / kg, and the order of the constant element content is Si O2Al2O3Fe2O3K2OMg ONa2OCa O. Degree of migration and leaching, The strength of weathering soil formed from the relative enrichment of Feo Alnk was observed from Ma Lan Loess L _ 1 to that of Ma Lan Loess L _ 1. 鈫扵ransitional loess Lt. 鈫扵he S _ 0 of paleosol increased gradually, and the L0 of Holocene loess decreased again. It was recorded that the climate of the region experienced the last glacial period (55.0-15.0 ka BP) cold and dry, early Holocene (15.0-8.5 ka BP) temperature and humidity, and the middle Holocene (8.5-3.1 ka BP) reached the highest temperature and humidity. The evolution process of cooling and drying in late Holocene (3.1-0.0 ka BP) .3 the element assemblage of Hanjiang loess is highly consistent with that of Luochuan, Wushan and Xiashu loess. Except for the constant element (Ca O) in different regions, the contents are very close and the variation of UCC standardized value is less than 0.25, which implies that they have similar aeolian sedimentary base at the beginning of weathering, but the chemical weathering intensity of loess in different regions is different obviously. Luochuan Loess, Hanjiang Loess, Wushan Loess, Lower Shu Loess, coincides with the spatial variation of modern monsoon climate in China, that is to say, the difference of loess weathering degree in different regions is mainly the result of the influence of East Asian Monsoon change.
【作者单位】：陕西师范大学旅游与环境学院;
【基金】：国家自然科学基金项目(41271108,41371029,41471071) 国家社会科学基金项目(14BZS070) 中央高校基本科研业务费专项基金(GK201704014)~~
【分类号】：S153

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