【作者】 何永峰；

【导师】 王建力；

【作者基本信息】 西南大学 ， 第四纪地质学， 2010， 硕士

【摘要】 长江三峡地区是研究长江地貌和环境演化的理想区域,且该地区沉积物的沉积历史与三峡地貌演化历史、青藏高原的隆升过程密切相关。本文通过巫山第四纪沉积物元素地球化学和矿物的特征以及其风化程度的判别,以期确定巫山第四纪沉积物的特征及其渊源。元素地球化学指标主要通过x射线荧光光谱仪获得沉积物的常量元素：Fe₂O₃、SiO₂、Al₂O₃、MgO、CaO、Na2O和K2O的含量；微量元素：Ga、Sr、Ba、Cu、Zn、Co、Ni、Cr和V的含量；稀土元素：La、Ce、Nd和Y的含量,分别与我国典型风成沉积物-洛川黄土、洛川古土壤、镇江下蜀土、西峰红粘土、宣城风成红土及其上陆壳（UCC）的常量元素、微量元素和稀土元素的平均含量对比研究,结果发现,巫山望天坪剖面第四纪沉积物的常量元素和微量元素的化学成分与以上典型风成沉积物具有较好的相似性,稀土元素也与黄土呈相似的变化规律,巫山第四纪沉积物具有风成沉积物的特征。对巫山沉积物利用X射线衍射分析得出：巫山第四纪沉积物的矿物组合主要以石英、云母和长石为主,其三者平均含量高达94%。再结合沉积物的风化程度判定,可以得出巫山第四纪沉积物与我国北方黄土的矿物特征相类似。结合元素地球化学指标及其矿物组成特征可以初步得出巫山：第四纪沉积物可能是风成沉积物,而且大部分来源于我国北方干旱的地区。其是研究三峡地区重要的环境变化载体。但是我们没有对采集样品进行测年以及对典型矿物的电镜扫描实验,也是本研究的不足。因此采集样品的风成微观形态证据尚需进一步探讨。更多还原

【Abstract】 The region of Yangtze River of Three Gorges is the most ideal place for studying Changjiang’s landform and environment evolution, and the sedimentary history of the sediments in this area closely related to the Three Gorges’ landform evolutionary history and the uplift of the Tibetan Plateau. According to the judgment to Quaternary sediments element geochemistry, minerals’ features and weathering degree on Wu Shan in this thesis so that fixes the Quaternary sediments’ features and origin. Element Geochemistry indicators can get the content of major elements of sediments, which are Fe₂O₃、SiO₂、Al₂O₃、MgO、CaO、Na₂O and K₂O by mainly means of X-ray Fluorescence Spectrometer, and the content of the trace elements which are Ga、Sr、Ba、Cu、Zn、Co、Ni、Cr and V. When we compared the content of rare earth elements Which are La、Ce、Nd and Y with the major elements, trace elements and the average content of rare earth elements from our country’s typical aeolian sediments that are Luochuan loess, Luochuan paleosoil, Zhenjiang Xiashu soil, Xifeng red clay, Xuancheng eolian red clay and the top of the crust, we found that the chemical composition of the Quaternary sediments’major elements and trace elements in the region of Wang Tianping profile in Wushan had the better similarity with all above typical aeolian sediments, The rare earth elements correlation also had the similar variation with the loess, and the Quaternary sediments in Wushan has the characteristics of the Aeolian sediments.Utilizing X-ray diffraction analyzed the sediments of Wushan can know that the mineral assemblage of the Quaternary sediments from Wushan are quartz, mica and feldspar. And the average content of them are highly up to 94%. Furthermore, combined with the weathering, we can found out that the mineral’ features of the Quaternary sediments from Wushan are similar with the loess in the north of our country. Combined with the indicators of element geochemistry and mineral composition features, we can roughly know that the Quaternary sediments from Wushan maybe the Aeolian sediments, and the most part are from the drought region of the north in our country. Actually,it is the important environment changing vector for researching Three Gorges. But we did not collect samples for dating and its impact on the typical scanning electron microscopy of minerals experiment, which is also the shortage of these. Therefore, samples collected evidence of aeolian morphology requires further study.更多还原