摘要
桂林地区降水及茅茅头大岩滴水滴速和现代碳酸盐的碳氧同位素研究表明:(1)滴水沉积的δ18O达到了同位素沉积平衡,洞穴滴水的δ18O与同期降雨的δ18O值呈正相关关系;(2)在旱季和湿季交替时,滴水δ18O值滞后于降雨δ18O,受活塞效应的影响;(3)δ13C难以达到同位素沉积平衡,主要受滴水动力学影响;(4)同一洞穴不同滴水对环境的响应不同,如果洞穴顶板覆盖较厚,水分在土壤和岩层中滞留时间较长,滴水则反映受到平滑作用的降雨,反之则波动较大。
Research on cave drip-water and modern carbonate sediment in Guilin area through water discharge and carbon and oxygen isotope gives the results as follows： （1） Oxygen isotope of cave secondary sediment reaches isotopic equilibrium while negative relationship between cave drip-water and rain oxygen isotopes relies on meteoric precipitation and natures of soil and rock above the cave. （2） Oxygen isotope of drip-water exhibits one month lagging behind that of rain due to piston effect during seasonal interval and storm event. （3） Carbon isotope is farther from equilibrium due to different dynamic characteristics than oxygen isotope： soil and texture and structure of overlying rock from which water derives play instrumental roles in carbon isotope fluctuation both in water and secondary sediment. （4） Stable discharge of dripwater from thick rock cover on the cave becomes a good proxy for meteoric rain and is then applied to environment research.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2008年第4期117-124,共8页
Marine Geology & Quaternary Geology
关键词
滴速
稳定同位素
降雨
桂林
drip-water rate
stable isotope
precipitation
Great Cave Guilin
