青藏高原东部红原地区7380年来环境演变

发布时间：2018-06-18 19:53

本文选题：青藏高原 + 红原泥炭　；参考：《华东师范大学》2017年硕士论文

【摘要】：红原泥炭位于青藏高原东部四川省西北地区,当地气候深受西南季风影响。通过对青藏高原东部地区红原泥炭的烧失量、地球化学元素、总汞含量以及色度指标的研究,认为红原泥炭的各项指标能够很好地反映红原泥炭地区7380年以来的环境变化特征。不同的代用指标中反映了多次气候变冷事件,分别发生在7200、6300、5200、4500、4200-4000、3400～3200、1800～1600 yrBP。除去2000～1620 yrBP时间段的人为因素干扰之外,可以将7380～2000yrBP分为四个阶段:(1)7380～6500yr BP,暖湿增强气候波动剧烈阶段;(2)6500～5100 yr BP,向冷干发展气候变化平稳;(3)5100～4000 yrBP,持续向冷干方向发展,气候波动明显;(4)4000～2000 yrBP,温度变化平稳,湿度波动明显。红原泥炭总汞含量和烧失量周期分析表明:红原地区存在2500、1250、910、550、420、360、310、280、200、160、125和75年准周期,这些周期在太阳活动变化、太阳轨道周期变化以及西南季风周期中都具有一定体现。青藏高原的加热作用会影响季风的强度,太阳辐射量对青藏高原的加热作用强度具有重要意义。总汞含量和烧失量的变化趋势与太阳辐射轨道周期变化规律一致,红原泥炭显示的7200、6800、5400、4600、4200、3300以及2700 yr BP变冷事件都对应了太阳辐射量的大幅度减弱,印度河河口沉积物δ18O含量与烧失量和总汞含量的变化趋势具有很高的一致性,证明太阳辐射变化的确能改变西南季风的强度。
[Abstract]:The red peat is located in the northwest of Sichuan Province in the eastern part of Qinghai-Xizang Plateau, and the local climate is deeply influenced by the southwest monsoon. Based on the study of the loss of red peat, geochemical elements, total mercury content and chromaticity index in the eastern part of Qinghai-Xizang Plateau, it is concluded that each index of red peat can well reflect the characteristics of environmental changes in the region since 7380 years. A number of climatic cooling events were reflected in different proxy indices, which occurred in 7200 ~ 6300 ~ 5200 ~ 4500 ~ 4200-4000m ~ 3200 ~ 1800 ~ 1600 ~ 1600yrBP, respectively. In addition to the interference of human factors in the period of 2000 ~ 1620 yrBP, 7380 / 2000yrBP can be divided into four stages: 1: 1 / 1 / 733 80 / 6500yr BP, 26.500 / 5100yr BPs during the intense climate fluctuation stage, 35100000 yrBPs, 35100000 yrBPs, and 351004000yrBPs, which continue to develop in the direction of cold drying. The climate fluctuation is obvious, the temperature change is stable and the humidity fluctuates obviously. The analysis of the total mercury content and the period of burning loss of peat in Hongyuan shows that there are 2500N 12509105504203310280200160125 and 75 years quasi periods in Hongyuan area. These periods are reflected in the changes of solar activity, the cycle of solar orbit and the cycle of southwest monsoon. The heating of the Qinghai-Tibet Plateau will affect the intensity of the monsoon, and the amount of solar radiation is of great significance to the intensity of the heating over the Qinghai-Xizang Plateau. The variation trend of total mercury content and loss of total mercury is consistent with the periodic variation of solar radiation orbit. The cooling events of 7200 ~ 6800 ~ 5400 ~ 4400 ~ 4200 ~ 4200 ~ 3300 and 2700 YR BP indicate that the solar radiation decreases greatly in the red peat. The variation trend of 未 18O content in the sediments of the Indus estuary is very consistent with that of the burning loss and the total mercury content, which proves that the solar radiation change can change the intensity of the southwest monsoon.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P532

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