Research On The Seasonal Variation Of Trace Elements In Drip Water Of Kaiyuan Cave In Shandong Peninsula And Their Implications For Climate And Environment

Secondary cave sediments had become an important carrier of the reeords, which showthe ancient climate change of the karsts area, especially reflected in the high-resolution、short-time scale studies. Using the trace element the stable carbon and oxygen in the secondarycave sediments to reconstruct the ancient climate, and using high-precision U/Th datingtechniques on a series of comparative study of abrupt climate change events to reconstructthe high-resolution ancient climate.However, in the use of secondary cave sediments inancient climate reconstruction process,there are some study notes that its records areinconsistent with the ancient climate change, the study of the cave drip water help us toaccurately interpret thecave sediments, ancient climate information.This paper chooses Boshan County, Zibo City, Shandong Peninsula jintian hole asthe research object, analysis of nine days of cave drip hydrological and geochemicalcharacteristics of elements from the two aspects of hydrology and water chemistry. This studyfrom January2012to Kaiyuan cave drip water cave environment indicators were continuousmonitoring of a hydrological year, Monitoring indicators include cave water conductivity, PHvalue, temperature, drip droplets rates and Ca2+, Mg2+, Sr2+, Ba2+ion concentration andelemental ratios of trace elements.Meanwhile cave environmental indicators such astemperature, humidity, CO2concentration has also been a long-term dynamic monitoring. Bystudying the temporal and spatial variation of these indicators, to explore the seasonalchange of trace elements of cave drip and its relationship with climate and environment. Theresults show, environmental indicators of Caves and cave drip trace elements are significantseasonal variation. This seasonal variation is mainly affected by the local climate andenvironment changes, especially the change of temperature and precipitation. It can beinferred that the cave drip major come from local rainfall. Although there are certain responserelationship between the drip points of Kaiyuan cave with climate change in the outsideenvironment. But the content of trace elements in different drip points and lag time inresponse to rainfall is not identical. The fundamental reason is the migration path of water inthe cave roof overlying soil and bedrock fissure of different substances on the drop of waterhas a great influence. The roof rock thickness and water transport time will affect the lag time of response of water environment.The main results are as follows:(1)In a hydrological year study period, the cave environment indicators little seasonalvariation in temperature and humidity, and seasonal variation of CO2concentration is veryobvious, and there are certain response relationship with climate change of the outside world.In addition, The cave environment index differences exist certain space, especially the cavetemperature is performance the most obvious, With the increase of the cave depth increased.The change in temperature and humidity outside the hole and CO2concentrations consistentwith local temperature and precipitation changes.(2) There are certain characteristics of temporal and spatial variation of water cave PH andconductivity. Among them, The value of pH is lower in summer, winter high, Seasonalvariation of pH conductivity contrast, Performances High in summer, low in winter,5#waterpoint conductivity (EC) is slightly less than3#drip points.(3) This paper selected two points are all perennial drip, there is "piston effect" in the earlyrains.Two drip points drip rate on local rainfall have certain lag. This lag is mainly affected bythe thickness of the roof rock, roof characteristics and the size of the matrix seepage of waterflowing through the pipe, the length of the flow path and so on.(4) Through the analysis of the trace element concentration2drop points of Kiayuan cave,Range and mean trace elements of cave drip water are different. This difference ismainly affected by overlying soil and bedrock composition and properties, roof bedrockfissure in the migration path and soil-water-rock interaction time and so on.(5)Trace elements ion concentrations of two drip point in Kaiyuan cave showed seasonalvariation characteristics that the dry season low, the rainy season high. In the early stage ofrainfall, appeared an obvious trend of rising. Combined with the local airtemperature, rainfall and other climate environmental data, the seasonal variation of traceelements ion concentrations in drip water is affected by both the hydro-geological conditionsand the local climate and environment changes.(6)The study found, the change trend of Mg/Ca,Sr/Ca ratio and Ba/Ca ratio in dripwater is not consistent. Due to the local precipitation affection, Mg/Ca,Sr/Ca ratio in dripwater showed an obvious seasonal variation. But the Ba/Ca ratio in the drip water not showedobvious seasonal variation. In addition to the affection of the precipitation, they are also affected by the interference of other geological and hydrological factors. Therefore, we cansee that Mg/Ca,Sr/Ca ratio in drip water has a better indication to external precipitation. Butthe indication of Ba/Ca ratio in the drip water is not obvious. They may indicate strong degreeof microbial activity in the overlying soil on the cave.