Estimation of carbon isotope equilibria for calcite precipitation by on-site analysis

石笋碳同位素比值很大程度上反映了土壤有机碳的碳同位素比值与植被有关的碳同位素比值。在方解石沉积过程中，土壤中二氧化碳的碳同位素比值被记录到喷发碳酸盐中时，碳同位素比值可能受碳同位素分馏规律和其他效应的控制。明确了利用石笋碳同位素比值作为古植被信息的判别函数。现场测量是在一个洞穴中进行的。在计算机模拟中，方解石降水的碳同位素平衡受滴水量的影响。为了对碳同位素比值模拟结果进行评价，在洞穴中建立了方解石自动沉积系统。这些现场测量的结果被实验室规模的实验所检验。

The stalagmite carbon isotope ratio values largely reflect those of soil carbon dioxide derived from organic carbon associated with carbon isotope ratio values dependent on vegetation. When carbon isotope ratios of carbon dioxide in the soil are recorded into speleothem carbonate during calcite precipitation, the carbon isotope ratios may be controlled by the carbon isotope fractionation laws and other effects. We were clarified a discriminant function of paleo-vegetation information using carbon isotope ratio of stalagmite. The on-site measurement was done in a cave. As for a computer simulation, the carbon isotope ratio equilibrium of calcite precipitation was affected by a rate of drip water supply. For the evalation of simulation results of carbon isotope ratio, the automatically calcite deposition system was built in caves. These results of on-site measurement was examined by a experiments at the laboratoryscale.