土壤碳酸盐碳氧同位素特征及其在古环境重建中的应用OA

Objectives:As a product of pedogenic processes,pedogenic carbonate plays a vital role in both paleoenvironmental reconstruction and Earth's surface system study.The review begins by systematically examining the composition,classification,formation mechanism and environmental factors of pedogenic carbonate.And then,it synthesizes its C-O isotopic composition characteristics,applications in paleoenvironmental reconstruction,and advances in pedogenic carbonate chronology. Results:The C-O isotopic signatures of pedogenic carbonate are primarily controlled by key parameters such as soil-respired CO2 concentration,soil water and soil temperature,providing reliable foundation for the quantitative reconstruction of paleoatmospheric CO2 levels,paleo-C3/C4 biomass and paleoprecipitation,paleotemperature,paleoelevation.Integrating diverse chronometric methods,particularly high-precision U-series dating,soil carbonate C-O signatures enable quantitative reconstruction of multidimensional paleoenvironmental parameters,serving as a crucial terrestrial environmental proxy.Meanwhile,significant challenges persist due to the complexity of pedogenic processes,including pedogenic carbonate spatiotemporal heterogeneity,selective preservation of environmental signals and burial diagenetic overprinting isotopic systems etc. Conclusions:Future research on pedogenic carbonate,such as dynamic modeling of formation processes,constraining key parameters,and isotopic processes during diagenesis will further enhance its application and reliability in paleoenvironmental reconstruction.