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黄龙钙华沉积速率及景观演化研究
Travertine Deposition Rate and Landscape Evolution in Huanglong Area
【作者】 朱静；
【导师】 万新南；
【作者基本信息】 成都理工大学 ， 环境科学， 2009， 硕士
【摘要】 钙华由泉、河、湖水的次生碳酸钙过饱和而形成的地表沉积。钙华是环境、气候、生物等信息的载体。世界上其它地区的钙华多在岩溶地区发育,而黄龙钙华景观形成过程特殊。黄龙钙华的分布受地下水出露的控制,被钙华胶结的冰碛层是浅层地下水活动的隔水底板。黄龙地区特殊的地质背景和水文特征是黄龙钙华景观形成的重要前提条件,宽缓的沟谷成为黄龙沟内地表水、地下水缓慢径流、运移的良好场所。关于黄龙地区地质、地貌、水文、生物、旅游等方面的调查研究,前人的研究已经相当深入。近些年,黄龙核心景区水流改道与变迁,水循环转化段地表水严重漏失,使黄龙钙华景观水减少、部分钙华池干涸,个别地段景观变黑、开裂甚至坍塌。本文通过室内钙华沉积模拟实验、野外监测点的水质分析资料以及钙华沉积速率测定实验,估算黄龙钙华沉积速率。本文的创新点在于,从钙华沉积-溶蚀的对立过程研究其沉积速率与溶蚀速率在空间上的变化规律,进而研究黄龙钙华景观的成长、演化与消亡过程。在该课题研究中提出了黄龙钙华沉积具有“时空动态变化性”,并不存在常态沉积速率的观点,认为黄龙钙华沉积具有时段性,钙华形成的地质时期初期,其速率比较均一,达10-20mm/a,而中后期水量开始重新分配,钙华沉积与溶蚀作用并存。特别是现今阶段,钙华沉积表现出明显的时空差异,某些地段的钙华沉积速率可达0.37-5.57mm/a,某些地段只是维持沉积-溶蚀的动态平衡状态,局部地段钙华未呈现沉积状态,而是呈现溶蚀状态,并形成地下管道和洞穴,某些地段甚至出现钙华消亡的现象。气候环境、水动力条件、水物理化学条件、微地貌环境的变化,藻类的生物效应,这些影响因素只是外因,而其内因中起着主导作用的是黄龙钙华含水层的水文地质条件的变化。地表漫流方式的变换与地下水改道,新的地下钙华通道的形成、景观水漏失的加大,造成局部瀑布等景观衰退或位置转移。钙华的完整结构和水流状态的破坏可能加速钙华衰退、消亡演化。黄龙钙华景观退化主要是由黄龙的水文地质??引起的。在研究黄龙钙华沉积速率和景观演化的基础上,完善钙华沉积理论,为黄龙钙华景观的科学保护提出切实可行的措施与建议。
【Abstract】 Travertine deposits on the surface of the karst spring, the river, the lake where format the secondary calcium carbonate, is the information carrier of environment, climate, biology and so on. Other regions of the world, travertine more exist in the karst area, but the formation of travertine landscape is a special in Huanglong. The distribution of travertine controlled by the appearing of karst groundwater in Huanglong, the moraine layer cemented with travertine is the impermeable floor in shallow groundwater activities. The special characteristics of geological and hydrological background is an important prerequisite for the travertine landscape formation in Huanglong, the wide and slow valley is a good place, surface water and groundwater riched in Heavy calcium carbonate runoff slowly in Huanglong.Previous research on the geology, geomorphology, hydrology, biology, tourism has considerable depth in Huanglong area. In recent years, the main reasons leading to reducing travertine landscape and water serious loss in Huanglong, is diversion of core landscape water, and changes in surface water cycle, part of travertine pool dried up, cracked or even collapsed. Through the simulation of travertine deposition in laboratory test, the analysis of water quality and field experiment estimate the travertine deposit rate. The paper’s innovation analyzes the change regularity in space of the deposition rate and corrosion rate in the travertine deposition-dissolution process, and then study the the process of growth, evolution and extinction of travertine landscape in Huangl??In the research, it proposed the view that travertine deposition of a "dynamic change of time and space", it doesn’t exist normal deposition rate; that with a time of travertine deposition in Huanglong, in the early geological period of travertine formation, and the rate is relative uniform, up to 10-20mm/a, and the re-allocation of water appears in late period, travertine deposition co-exist with the dissolution.Especially, it shows clear differences in time and space in this stage, the travertine deposition rate in some sections up to 0.37-5.57mm/a, certain areas maintain the deposition- solution dynamic balance, in some areas, travertine is not a state of deposition but a state of dissolution which formate the buried pipes and caves, there’s the phenomenon of the disappearance of travertine. Climate environment, hydrodynamic conditions, water physico-chemical conditions, micro-topography environment, the biological effects of algae, which only external factors, and the travertine aquifer hydrogeological conditions plays a leading role as internal factors in Huanglong. Transform the way of the surface flooding and groundwater diversions, the new formation of underground travertine channels, the greater loss of landscape water, resulting recession in the local landscape, such as falls, or transfermation of the location. The destruction of the state of travertine structure, and the integrity of the flow may accelerate the recession, demise evolution of travertine.The essence of travertine landscape degradation is the hydro-geological problems in Huanglong. On basis of research in travertine deposition rate and landscape evolution, perfecting the theory of travertine deposition, protection of the travertine landscape in scientific and practical measures and recommendations in Huanglong.