摘要
成壤过程中形成的次生碳酸盐(成壤碳酸盐)是古气候研究中的重要材料,在过去研究中被广泛用来重建大气CO_(2)浓度、古植被(C_(3)、C_(4)植被)、古高程、降雨量和温度的演化。然而,和绝大部分其它古气候指标一样,成壤碳酸盐指标(稳定碳氧同位素、微量元素等)也受到多个气候因子的控制而具有多解性,因此需结合多个指标耦合分析才能获取可靠的古环境信息。随着近年来同位素测试手段的发展,在传统^(18)O/^(16)O的基础上,叁氧同位素(^(17)O/^(16)O)测试越来越多地被应用于古气候领域。成壤碳酸盐继承了土壤水的氧同位素信号,可以重建土壤水的^(17)O异常。土壤水的Δ′^(17)O主要受控于土壤水的蒸发过程,可反映空气湿度的变化。文章详细介绍了成壤碳酸盐叁氧同位素的理论基础,结合现有的土壤水叁氧同位素模型,定量探讨了各个气候因子对成壤碳酸盐叁氧同位素的影响。
The secondary carbonate formed during the soil formation process(pedogenic carbonate)is a crucial material in paleoclimate studies.In previous research,it has been widely used to reconstruct atmospheric CO_(2) concentrations,paleoaltimetry,the evolution of regional paleovegetation(C_(3),C_(4) plants),precipitation,and temperature.However,like most other paleoclimate indicators,proxies based on pedogenic carbonate(such as stable carbon and oxygen isotopes,trace elements,etc.)are influenced by multiple climate factors,resulting in ambiguity.Therefore,obtaining reliable paleoenvironmental information requires the integration of multiple indicators.With the recent development of isotope testing methods,in addition to the traditional ^(18)O/^(16)O,triple oxygen isotope analysis(^(17)O/^(16)O)has been increasingly applied in paleoclimatology.Pedogenic carbonates inherit the oxygen isotope signal of soil water.Combined with the carbonate-clumped isotope temperature,the ^(17)O anomaly of soil water can be reconstructed.The soil-water-Δ′^(17)O is mainly controlled by the evaporation process,thus providing information about past humidity.This article provides a detailed introduction to the theoretical basis of pedogenic carbonate triple oxygen isotopes.It quantitatively discusses the impact of various climate factors on pedogenic carbonate triple oxygen isotopes using existing soil water triple oxygen isotope models.
作者
达佳伟
DA Jiawei(Department of Earth and Planetary Sciences,The University of Texas at Austin,Austin)
出处
《高校地质学报》
CAS
CSCD
北大核心
2024年第3期241-252,共12页
Geological Journal of China Universities
基金
国家自然科学基金(42030503)资助。
关键词
叁氧同位素
成壤碳酸盐
古气候
古湿度
triple oxygen isotopes
pedogenic carbonate
paleoclimate
relative humidity
