洞穴次生碳酸盐沉积稳定碳同位素研究

Speleothem Stable Carbon Isotope and its Application for Paleoclimatic and Paleoenvironmental Reconstructions: A Review

对国内外有关洞穴次生碳酸盐沉积(石笋)稳定碳同位素值(δ^(13)C)的研究成果进行了梳理和归纳总结,介绍了影响石笋δ^(13)C值变化的因素(如植被(包括植被类型和生物量效应)、土壤过程、大气CO_2、岩溶地下水水文(包括地下水的水动力条件、水-岩相互作用和先期碳酸盐沉积等)),同时介绍了一些模型研究中对影响石笋δ^(13)C值的某些具体气候环境因素(如滴水快慢或时间间隔、通风强度、地下水流动路径等)进行的定量评估.综合1992—2017年对洞穴石笋δ^(13)C值的研究成果,指出洞穴内滴水的CO_2去气作用可能是影响石笋δ^(13)C值变化的关键机制,建议在今后的研究中对此给予高度关注.

The investigations into speleothem stable carbon isotope(δ13C)are summarized.The factors influencing speleothemδ13C,such as changes in vegetation(including C3plant to C4plant ratio and/or bio-productivity),soil processes,atmosphere CO2,karst grounder hydrology(including hydrodynamic of karst groundwater,water-rock interaction,prior calcite precipitation,etc.),are introduced one by one.Meanwhile some model simulations,which were used to quantitatively estimate the effects on speleothemδ13C of specific factors such as dripping interval,cave ventilation intensity,flowing path and distance of groundwater and so on,are also introduced.According to the results of existing researches on speleothemδ13C,it is suggested that CO2degassing of dripping water may be a key factor influencing speleothemδ13C values and deserves more attention in future studies.