本文選題：紅土堆積 + 地球化學��； 參考：《中國地質(zhì)大學(北京)》2015年碩士論文

【摘要】：中國南方的紅土堆積蘊含了大量的亞熱帶-熱帶地區(qū)第四紀古氣候變遷和古環(huán)境演化信息,在恢復環(huán)境演化過程方面具有十分重要的意義。但是在利用紅土堆積物反應古氣候變化的指標選取尤其困難。近幾年地球化學方法在風塵堆積反應古氣候研究以及物質(zhì)起源判斷上發(fā)揮了重要作用。本文對九江地區(qū)的紅土堆積物進行常量元素測試分析,對紅土堆積的成因進行判斷,以揭示長江中下游古氣候演化的過程。得出以下結(jié)論：通過紅土與洛川黃土的常量元素平均值和UCC的對比,表明九江紅土與北方黃土常量元素的分布模式相似,同時與UCC分布模式也相似,指示了九江紅土起源于上地殼,是典型的風成堆積物。將九江剖面的網(wǎng)紋紅土、下蜀土和北方洛川地區(qū)的黃土、古土壤之間抗風化能力比較強的Si、Al、Ti元素的比值進行投影分析,顯示了九江紅土具有較高的TiO2/Al2O3值、SiO2/Al2O3值和較低的SiO2/TiO2值。同時九江地區(qū)的紅土和洛川地區(qū)的黃土-古土壤的投影區(qū)域具有明顯的差異性,表明了九江紅土的物質(zhì)來源不是來自北方荒漠。同時網(wǎng)紋紅土和下蜀土的投影區(qū)域近乎相同,略有差異,經(jīng)過對整個剖面的難遷移元素的分析,推斷網(wǎng)紋紅土和下蜀土的物質(zhì)來源相同,兩者之間的略微差異是由于后期風化不同造成的。運用九江剖面的網(wǎng)紋紅土、下蜀土和北方洛川地區(qū)的黃土、古土壤之間的A-CN-K圖和化學風化系數(shù)CIA變化趨勢顯示,九江紅土達到了強烈的風化階段,北方黃土處于中等風化階段,顯示了九江地區(qū)的成壤環(huán)境更為溫暖濕潤。在九江地區(qū)的紅土中,網(wǎng)紋紅土的風化強度明顯強于下蜀土,通過化學風化參數(shù)系統(tǒng)分析,指示了九江剖面的的紅土沉積過程中由暖濕的氣候環(huán)境向干冷的氣候發(fā)展的長期變化趨勢。
[Abstract]:The accumulation of red soil in southern China contains a large amount of information on the Quaternary paleoclimate change and paleoenvironmental evolution in the subtropical and tropical regions, which is of great significance in restoring the process of environmental evolution. However, it is particularly difficult to select indicators to reflect paleoclimate change by using laterite deposits. In recent years, geochemical methods have played an important role in the study of paleoclimate and the judgement of material origin. In order to reveal the process of paleoclimate evolution in the middle and lower reaches of the Yangtze River, the elements of the laterite deposits in Jiujiang area are tested and analyzed in this paper. The following conclusions are drawn: through the comparison of the average value of constant elements and UCC of laterite and Luochuan loess, it is shown that the distribution pattern of constant elements in Jiujiang red soil is similar to that of northern loess, and the distribution pattern is similar to that of UCC. This indicates that Jiujiang laterite originated from the upper crust and is a typical aeolian deposit. Based on projection analysis of the ratios of Si-Al-Ti elements, which have strong weathering resistance between Xiashu soil and Loess in Luochuan area, Jiujiang section, it is shown that Jiujiang laterite has higher TiO2/Al2O3 value and lower SiO2/TiO2 value than Sio _ 2 / Al _ 2O _ 3 value. At the same time, the red soil in Jiujiang area and the loess paleosol projection region in Luochuan area have obvious differences, which indicates that the material source of red soil in Jiujiang area is not from the northern desert. At the same time, the projection area of reticulated red soil and Xiashu soil was almost the same, which was slightly different. Through the analysis of the hard to migrate elements in the whole section, it was inferred that the material sources of reticulated red soil and Xiashu soil were the same. The slight difference between the two is due to the later weathering difference. Using the A-CN-K diagram and chemical weathering coefficient CIA variation trend between the net red soil of Jiujiang section, Xiashu soil and Loess in Luochuan area of northern China, it is shown that the red soil of Jiujiang has reached a strong weathering stage, and the loess in the north is in the middle weathering stage. It shows that the earthen environment in Jiujiang area is warmer and wetter. In the red soil of Jiujiang area, the weathering intensity of reticulated red soil is obviously stronger than that of Xiashu soil, and the chemical weathering parameters are systematically analyzed. It indicates the long-term change trend from warm and wet climate environment to dry and cold climate in the process of laterite deposition in Jiujiang section.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P532;P59

【參考文獻】

相關(guān)期刊論文 前2條

1 盧演儔;黃土地層中CaCO_3含量變化與更新世氣候旋忯[J];地質(zhì)科學;1981年02期

2 喬彥松,郭正堂,郝青振,吳文祥,姜文英,袁寶印,張仲石,魏建晶,趙華;皖南風塵堆積-土壤序列的磁性地層學研究及其古環(huán)境意義[J];科學通報;2003年13期

，

本文編號：1892854