喀斯特石漠化地区洞穴滴水元素特征分析

发布时间：2018-11-09 11:07

【摘要】：洞穴滴水元素作为一种环境替代指标,旨在反映地表气候环境与物质来源,以及在重建古环境古气候方面有着重要作用,已受到国内外学者的广泛认可。目前,有关石漠化地下环境的研究相对较少,利用洞穴滴水元素探寻石漠化地表环境信息具有较大的研究潜力。本研究以贵州3个典型石漠化地区6个地表不同石漠化等级洞穴(安顺地区玄母洞和石将军洞、毕节地区朝营洞和韩家冲洞、花江地区大消洞和荣发洞)为例,通过对6个洞穴的滴水进行了为期1年的月动态监测,以及针对石将军洞滴水进行了2次降雨响应监测;分析了洞穴上覆土壤、基岩对滴水元素特征的影响,讨论了滴水元素的季节变化特征及其环境意义,重点探讨了洞穴滴水元素的降雨响应特征及其水文地球化学过程,首次揭示了洞穴滴水的石漠化环境效应,以期为石漠化环境监测研究提供科学依据。研究结论如下:(1)石漠化地区地表土壤的地球化学特征主要受到土壤侵蚀与母岩风化成土作用的影响。在相同岩性条件下,石漠化程度越高,土壤pH越高。受母岩岩性影响,灰质白云岩地区土壤pH高于石灰岩地区,土壤Mg含量低于灰质白云岩地区。受母岩风化成土作用的影响,安顺研究区与花江研究区洞穴的地表石漠化等级越高,地表土壤Mg含量越高。此外,洞穴沉积土因在沉积过程中长期受到滴水的化学侵蚀作用影响,表现出pH与元素含量高于地表土壤,且沉积土与滴水之间各元素均表现出明显的正相关关系。(2)地表土壤与基岩发育特征是影响滴水离子浓度的主要因素。洞穴上覆地表石漠化等级越高,洞穴滴水的离子浓度越低。通过对比发现,基岩岩性差异导致滴水中的Mg2+浓度具有明显差异,石灰岩地区洞穴滴水的Mg/Ca与Mg/Sr比值远低于灰质白云岩研究区的洞穴滴水。(3)6个洞穴的滴水滴率均表现出对大气降雨的响应变化,呈现出滴率随降雨量的升高而增快,随降雨量降低而减慢的变化规律。对比发现,在相同研究区内,石漠化程度越严重,其洞穴滴水的滴率对大气降雨的响应越敏感,季节变幅越大。潜在石漠化的玄母洞和朝营洞、轻度石漠化的大消洞滴水pH值呈现出雨季偏低、旱季偏高,电导率呈现出雨季偏高旱季偏低的变化特点;而中度石漠化的石将军洞、强度石漠化的韩家冲洞和荣发洞滴水pH值呈现出雨季偏高、旱季偏低,电导率雨季偏低旱季偏高的变化特征。(4)受地表石漠化差异的影响,滴水离子浓度的季节性变化呈现出显著差异。潜在石漠化的玄母洞和朝营洞、轻度石漠化的大消洞滴水离子浓度呈现出雨季高、旱季低的变化规律,且滴水元素受到上覆土壤的贡献较多;而中度石漠化的石将军洞、强度石漠化的韩家冲洞和荣发洞滴水离子浓度呈现出雨季低、旱季高的相反变化规律,且滴水元素受到上覆基岩的贡献较多。其中,玄母洞、石将军洞、大消洞、荣发洞的滴水均受到了明显的前期方解石沉淀作用。(5)降雨监测研究结果表明:石将军洞受地表石漠化发育的影响,降雨在地表土壤层滞留时间短,而在基岩中的运移时间相对更长;洞穴滴水表现出对大气降雨响应时间快的特点。降雨致使石将军洞滴水点上覆的水—土—岩作用增强,导致滴水中溶解的离子浓度与pH值随降雨响应相应升高。通过相关性分析得出,石将军洞滴水中Ca、Mg、Sr元素的来源较为一致,滴水受到的前期方解石沉淀作用显著,其地球化学特征受到洞顶基岩的贡献程度较大。因各滴水点上覆的土壤发育程度、基岩裂隙管道、渗流路径、水—土—岩作用的差异,各滴水点在降雨响应中的水动力作用类型与滴水元素的时空变化差异较大。
[Abstract]:The water-dripping element of the cave is an environmental replacement index, which is designed to reflect the surface climate environment and material source, and has an important role in the reconstruction of the ancient climate, and has been widely accepted by the domestic and foreign scholars. At present, the research on the underground environment of the rocky desertification is relatively small, and the water-dripping element of the cave is used to search the information of the surface environment of the rocky desertification, which has great research potential. This study is an example of the six surface different stone-level caves in the three typical stone-stone areas in Guizhou (Anshun area, the main cave and the cave of the stone, the area of Bijie and the cave in the camp and the tunnel of the Han's, the large and the green-emitting holes in the Hujiang area). Through a 1-year dynamic monitoring of the water drop in 6 caves, and 2 rainfall response monitoring for the drip of the stone general tunnel, the effects of the overlying soil and the bedrock on the characteristics of the water drop elements are analyzed, and the seasonal variation characteristics and the environmental significance of the drop elements are discussed. The rainfall response characteristics and the hydrological and geochemical processes of the water-dropping elements in the cave are discussed, and the environmental effects of the cave water drop are first revealed, with a view to providing the scientific basis for the study of the rock-water environment. The results of the study are as follows: (1) The geochemical characteristics of the surface soil in the Shifang region are mainly affected by the soil erosion and the weathering of the parent rock. In the same lithological condition, the higher the level of the rock, the higher the pH of the soil. Under the influence of the lithology of the parent rock, the soil pH in the dolomite area of the gray matter is higher than that of the limestone area, and the content of the Mg in the soil is lower than that of the dolomite of the gray matter. The higher the level of the surface stone, the higher the content of Mg in the surface of the study area of Anshun and Hujiang. In addition, the cave-deposited soil is affected by the chemical attack effect of the water drop during the deposition process, and shows that the content of the pH value and the element is higher than that of the surface soil, and all the elements between the deposition soil and the water drop have obvious positive correlation. (2) The surface soil and the development of the bedrock are the main factors that affect the concentration of the drip ions. The higher the level of the surface stone in the cave, the lower the ion concentration of the water in the cave. It is found that the difference of the lithology of the bedrock leads to a significant difference in the concentration of Mg2 + in the drop, and the ratio of the Mg/ Ca to the Mg/ Sr in the cave water in the limestone area is much lower than that of the cave in the study area of the dolomite in the gray matter. (3) The drop rate of the drop in 6 caves shows a change in response to the rainfall in the atmosphere, which shows that the drop rate is increased with the increase of the rainfall, and the change of the drop rate decreases with the decrease of the rainfall. It is found that, in the same study area, the more serious the level of the stone is, the more sensitive the drop rate of the water drop in the cave is to the response of the rainfall in the atmosphere, and the greater the seasonal variation. The water-dropping pH value of the deep hole of the potential stone-stone is low in the rainy season, high in the dry season, and the conductivity shows the change characteristics of the low dry season and the low dry season in the rainy season, and the stone general hole of the moderate stone-stone is The water-dropping pH value of the Han jianchong and the Rongfa Cave of Shifang of the intensity show that the rainy season is high, the dry season is low, and the conductivity and the rainy season are lower in the dry season. (4) The seasonal variation of the drop ion concentration was significantly different from the difference of the surface stone. The concentration of the water-dropping ion of the large-hole-eliminating hole of the potential stone-stone is high in the rainy season and the low in the dry season, and the water-dropping element is more than that of the overlying soil, and the stone-general hole of the medium-sized stone-stone is larger than that of the medium-sized stone-stone, The water-dropping ion concentration of the Han jianchong and the Rongfa cave of the intensity stone is lower than that in the rainy season and the high in the dry season, and the water dropping elements are more affected by the overlying bedrock. Among them, the water of the cave, the cave of the stone, the big hole and the glory of the cave were affected by the precipitation of the calcite in the early stage. (5) The results of the rainfall monitoring show that the surface soil layer has a short residence time, and the migration time in the bedrock is relatively long, and the water drop of the cave shows the characteristics of the rapid response time of the atmospheric rainfall. The results show that the concentration of dissolved ions and the pH value of the water drop in the water dropping point of the stone general tunnel are increased with the response of the rainfall. Through the correlation analysis, the sources of Ca, Mg and Sr elements in the drop of the stone general cave are more consistent, and the precipitation of the calcite in the early stage of the drop is significant, and the geochemical characteristics of the water drop of the cave top bedrock are relatively large. Because of the difference of the soil development degree, the bedrock fissure pipeline, the seepage path, the water-and-soil-rock, the water-dynamic action type of each drop point in the rainfall response and the time-space variation of the water-dropping element are large.
【学位授予单位】：贵州师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P641.3

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