重庆羊口洞滴水氢氧稳定同位素运移特征及地球化学特征

发布时间：2018-05-27 17:17

本文选题：羊口洞 + 氢氧同位素　；参考：《西南大学》2015年硕士论文

【摘要】：全球气候变化一直是当今世界广泛关注和研究的重大问题,其中全球气候变暖最为引起人们关注。全球气候变暖会导致一系列的生态环境问题,威胁社会安全以及人类的生存和可持续发展。而导致全球气候变暧的原因有诸多方面,一方面由于人类的生产活动及现代建设对气候的影响；另一方面由于宇宙自然不可抗力的因素。而现今所面临的气候变化现状,无疑是在地球气候系统本身的自然变化周期上,叠加了人类活动影响所导致的结果。应对全球气候变化需要在控制人类活动的同时,深刻了解地球气候系统本身的变化规律,两者缺一不可。其中,加强对古气候的研究则是了解地球气候系统变化规律的重要途径。本文以重庆金佛山羊口洞为主要研究场所,进行连续监测研究。探讨了大气降水一洞穴水氢氧稳定同位素的变化特征及气候意义；结合ENSO强度和季风指数分析大气环流对中国西南季风区大气降水中氢氧稳定同位素组成的影响；分析微量元素含量及比值变化特征以及对现代环境的响应机制,为利用这些指标进行古气候重建提供理论基础,得出如下结论：(1)羊口洞外大气降水及洞穴滴水δD和δ18O皆表现出夏秋季偏轻,冬春季偏重的整体趋势,主要是受降水水汽源地季节性差异的影响。但受洞穴上覆岩土层的调蓄作用影响,羊口洞δD和δ18O的季节变化幅度远小于大气降水,且较降水存在明显滞后性。各监测点滴水δD和δ180值季节变化差异较大,可能受滴水点上覆岩层裂隙管道发育、覆盖层厚度、岩溶水滞留时间、形成滴水前的运移路径、滴水点的高度和滴率、滴水点距离洞穴出入口的距离等多种原因影响。(2)羊口洞所在地区降水δ180与降水量、气温都呈负相关,表现出“降水量效应”和“负温度效应”。羊口洞滴水δ18O与降水量总体上呈负相关关系,而与温度的关系则呈现多样化：1#、2#、5#、6#监测点滴水δ180与水温、洞温不具备相关性；3#点滴水δ180与水温、洞温都呈正相关,相关系数分别为0.4055,0.3545；4#点滴水δ18O与水温、洞温都呈负相关,相关系数分别为-0.3746和-0.4449。温度相关性的多样化与各监测点δ18O季节变化差异较大有关。(3)羊口洞洞穴滴水δD和δ18O既表现出对降水的继承性,又存在变异性。但总体而言,羊口洞滴水δD和δ18O的季节变化不够明显,利用羊口洞石笋进行季节分辨率的古气候重建可能性较低。但羊口洞洞内滴水δID和δ1。O继承了当地大气降水的信息,羊口洞石笋δ18O可用于重建年际——十年际及更长时间尺度上的古气候变化。(4)大气环流对中国南方季风区降水有重要影响,羊口洞所在的中国南方季风区大气降水中氢氧稳定同位素组成与ENSO表现为正相关关系。当E1 Nino发生时,西太平洋副热带高压势力强盛,西北太平洋季风指数高,导致中国南方地区大气降水中氢氧稳定同位素值偏重,La Nina发生时,东南信风强,使西南季风增强,印度洋季风指数高,降水稳定同位素偏轻。此外,过量氘(d)的分析表明不同季节水汽源地的差异是导致当地大气降水中氢氧稳定同位素组成出现明显季节差异的主要原因。(5)羊口洞滴水Ca2+、Mg2+、Sr2+含量具有一定的季节变化特征,表现出雨季高,旱季低的特点。对1#～6#监测点进行逐个分析,可发现羊口洞洞穴滴水Mg/Ca、Sr/Ca具有旱季高、雨季低的特点,羊口洞洞穴滴水元素比值基本受大气降水控制,能够反映外界降水的变化。
[Abstract]:Global climate change has been a major issue of widespread concern and research in the world. Global warming is the most important cause of concern. Global warming will lead to a series of ecological environmental problems, threaten social security and human survival and sustainable development. There are many reasons for the global climate warming. Due to the effects of human production and modern construction on the climate, and on the other hand, the nature of the universe is naturally irresistible. The present situation of climate change is undoubtedly the result of the impact of human activity on the natural cycle of the earth's climate system itself. The response to global climate change is required. At the same time, it is indispensable to understand the change law of the earth's climate system itself, and the study of the paleoclimate is an important way to understand the change law of the earth's climate system. In this paper, we take the jinbuddha goats hole in Chongqing as the main research place and carry on the continuous monitoring and study. The change characteristics and climatic significance of Anami hydrogen and oxygen stable isotopes, and the analysis of the influence of the atmospheric circulation on the stable isotope composition of hydrogen and oxygen in the atmospheric precipitation in the southwest monsoon region of China by combining the ENSO intensity and the monsoon index, and analyze the changes in the content and ratio of trace elements and the response mechanism to the modern environment for the use of these indexes. The theoretical basis of climate reconstruction is provided, and the following conclusions are drawn as follows: (1) the atmospheric precipitation and the drop water delta D and delta 18O of the cave are all light in summer and autumn, and the overall trend of winter and spring heavy weight is mainly influenced by the seasonal difference of the water vapor source, but affected by the storage effect of the overlying strata on the caves, the seasons of delta D and delta 18O The variation range is far less than the atmospheric precipitation, and there is a significant lag in the precipitation. The variation of the seasonal variation of delta D and delta 180 value varies greatly, which may be developed by the fractured pipeline of the overlying strata, the thickness of the cover layer, the retention time of the karst water, the migration path before the drip water, the height and drop rate of the drip point and the drop point distance from the cave. (2) the precipitation in the area of the Yang Kou cave is negatively correlated with the precipitation, and the temperature is negatively correlated, showing the "precipitation effect" and "negative temperature effect". The water delta 18O of the sheep mouth hole is negatively correlated with the precipitation, while the relationship with the temperature is diversified: 1#, 2#, 5#, 6# monitoring drops of water delta 180 and water There is no correlation between temperature and cave temperature; 3# drop water [delta] 180 is positively correlated with water temperature and hole temperature, and the correlation coefficient is 0.4055,0.3545, and 4# drops water delta 18O is negatively correlated with water temperature and hole temperature. The correlation coefficient is respectively related to the variation of -0.3746 and -0.4449. temperature correlation with the seasonal variation of delta 18O in each monitoring point. (3) Caves Cave cave. The drop water delta D and delta 18O not only show inheritance and variability to precipitation, but in general, the seasonal variation of delta D and delta 18O in the drip water of the sheep mouth cavity is not obvious, and the palaeoclimate reconstruction with the seasonal resolution of the sheep hole stalagmite is lower. The stalagmite Delta 18O can be used to reconstruct the paleoclimate change on the interannual - ten interannual and longer time scales. (4) the atmospheric circulation has an important influence on the precipitation in the southern monsoon region of China. The stable isotope composition of hydrogen and oxygen isotopes in the atmospheric precipitation in southern China monsoon region located in the Yang Kou cave is positively correlated with the ENSO performance. When E1 Nino occurs, the Western Pacific vice The strong tropical high force and high monsoon index in the Northwest Pacific lead to the heavy hydrogen oxygen stable isotope value in the atmospheric precipitation in southern China. When La Nina occurs, the southeast monsoon is strong, the southwest monsoon is enhanced, the India Ocean monsoon index is high and the precipitation stable isotope is light. In addition, the analysis of excess deuterium (d) shows the difference of the water vapor source in different seasons. The difference is the main reason for the obvious seasonal differences in the composition of hydrogen and oxygen stable isotopes in local atmospheric precipitation. (5) the content of Ca2+, Mg2+ and Sr2+ in the drip water of Yang Kou cave has a certain seasonal variation characteristic, showing the characteristics of high rainy season and low dry season. The analysis of 1# to 6# monitoring points can be found that the drip of the cave of the sheep hole cave is Mg/Ca, and Sr/Ca has drought. With the characteristics of high season and low rainy season, the element ratio of dripping water in Yang Kou cave is basically controlled by precipitation and can reflect the change of external precipitation.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P532;P592

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