Study On Hydrogeochemical Characterristics Of Dolomite Cave Drip Water And Its Reponse To Enviromental Changes

The research of Drip water in the Karst cave which indicate the environment change has made important progress.The cave dripping water as the main source of calcium carbonate attracted a lot of researcher's attentions,and drop of water is a link which connected hole internal environment and external climate change signal,Pool Water in cave can be indirectly representative some characteristics of water environment of cave.The underground river system's characterized can be represent as overall hydrochemical characteristics of groundwater in the cave system,So through the analysis of hydrogeochemical characteristics in the cave system,it can reveal the characteristics of interannual and the inner link between the chemical composition.Based on this deduction on the hydrogeochemical process,can analysis the cave water hydrogeochemical process changes,By comprehensive analysis the characteristics of air CO₂ changes in cave,can reveal its influence on cave secondary carbonate sedimentary environment.Therefore,in order to explore the changes of hydrogeochemical process in Pixiao caves and its significance in environmental indicator,Combined with [National natural science foundation of china “The karst cave CO₂ migration changes mechanism and its influence on cave karst environment”.?41361081?],and other related subject.The earth system science theory,China karst dynamic system theory as the guiding ideology.In April 2015 to March 2016,monitoring the Pixiao Cave and underground river for a year,which location in Suiyang county,Guizhou.Use the Telaire-7001 portable infrared CO₂ device to monitoring air CO₂ real-time.Using the German production WTW Multi-3430 water quality analyzer and acid-base checkerboard field test the electrical conductivity?EC?,water temperature and p H in the cave water.Use German Merck production of alkalinity and hardness meter field of HCO3-and Ca²⁺ concentration determination in water,Use Varian companies in the United States production of VBTA MPX type inductively coupled plasma-optical emission spectrometer determin cation concentration in water.Anion ion chromatograph analysis by Dionex company IS90 type.And on the basis of these indicators,Use of the United States geological survey PHREEQC3.7 cryogenic hydrogeochemical analysis software,origin8.5 mapping software,SPSS19.0 statistical software and piper diagram,Gibbs diagrams and other analysis methods to investigate the relationship between the cave water between different indicators and its source.The paper mainly discusses the cave dripping hydrogeochemical process changes and the mutual influence between it and the internal and external cave environment,the following conclusions:?1?Cave water's conductivity?EC?and total hardness?TH?and the Ca²⁺,Mg²⁺ in the water samples present a good positive correlation.Combined the Piper diagram of water chemical types,can be indicates that the Ca²⁺,Mg²⁺ is the main controlling cation in the cave water,In the anion,Pixiao cave's drop point?DS1#?and the Dayu spring?DYQ?all belong to HCO₃^-—Ca²⁺—Mg²⁺.Show that in the two sample points,HCO₃^-ion occupy the dominant position in the anion.And the drop of point?DS2 #?,point CS1# and CS2#,three sample points presented type of SO₄^2-—HCO₃^-—Ca²⁺—Mg²⁺,Description the influence of SO₄^2-ion on water chemical type.?2?The drip rate and p H value in Pixiao cave changes response with the atmospheric precipitation variation.While there is no connection between the drop point in the gypsum geode and precipitation of the outside world,This shows that the thickness of cave roof played an important role in control of amount of migration time and migration which in cave water.The cave which with thicker roof,the drop point drop rate change is relatively stable throughout the year,and thinner hole in the roof will have a clear response with rainfall.?3?From the point of the element ratios of cave water,Four point ‘s Mg/Ca value have the characteristics of "single-peak",but the peak time difference,The peak time of Gypsum geode?DS2#?compared with Pixiao cave's?DS1 #?lag for about a month of time,That the greater the thickness of cave roof version,the signal of climate change on the outside the longer delivery time,In terms of the Mg/Ca ratio,main show the characteristics of "single control by Ca²⁺",While the Sr/Ca ratio reflects the feature of "double control by Sr²⁺,Ca²⁺ ions",This is associated with a large number of celestite deposits within the gypsum geode.?4?From the relationship between the ? P and mineral saturation index?SI?,Pixiao cave as a natural cave,The cave air CO₂ partial pressure [PCO₂?air?] to CO₂ partial pressure of water [PCO₂?water?] have little effect,? P under absolute control by PCO₂?water?.There are significant negative correlation relationship between? P and mineral saturation index?SI?,This relationship shows,?P has important instruction significance in Degassing – sedimentation of Calcium carbonate.And combined with classical theory,Pixiao cave's measured data shows that the existence of "apparent saturation index",About this conclution,it also needs to be studied further in the future.