Drip water isotopes in semi-arid karst: Implications for speleothem paleoclimatology
Drip water isotopes in semi-arid karst: Implications for speleothem paleoclimatology
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DOI：
10.1016/j.epsl.2014.03.034
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发表时间：
2014-06
影响因子：
5.3
通讯作者：
M. Cuthbert;Andy Baker;C. Jex;P. W. Graham;P. Treble;Martin S. Andersen;R. Ian Acworth
中科院分区：
文献类型：
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作者：
M. Cuthbert;Andy Baker;C. Jex;P. W. Graham;P. Treble;Martin S. Andersen;R. Ian Acworth
我们报告的第一个多年监测和模拟研究的结果滴沃茨的同位素组成在半干旱喀斯特地区。高时间分辨率滴率监测结合每月同位素滴水和降雨采样在大教堂洞穴，澳大利亚，表明滴水排放到洞穴发生不规则的，只有在偶尔的长时间和高容量的降雨事件，土壤水分亏缺和蒸散被克服。所有滴沃茨的水同位素组成都比加权平均年降水量重，有些水沿着当地的大气降水线下降，有些则趋向于蒸发水线。据推测，除了最初的降雨组成，蒸发的非饱和带水，以及渗透事件之间的时间，是占主导地位的过程，确定渗透水同位素组成。我们使用土壤水分平衡和同位素模型来检验这一假设。我们的研究报告，第一次，地下蒸发在改变滴水同位素组成的潜在作用，其含义的解释洞穴沉积物δ O 18记录从干旱和半干旱地区。
We report the results of the first multi-year monitoring and modelling study of the isotopic composition of drip waters in a semi-arid karst terrane. High temporal resolution drip rate monitoring combined with monthly isotope drip water and rainfall sampling at Cathedral Cave, Australia, demonstrates that drip water discharge to the cave occurs irregularly, and only after occasional long duration and high volume rainfall events, where the soil moisture deficit and evapotranspiration is overcome. All drip waters have a water isotopic composition that is heavier than the weighted mean annual precipitation, some fall along the local meteoric water line, others trend towards an evaporation water line. It is hypothesised that, in addition to the initial rainfall composition, evaporation of unsaturated zone water, as well as the time between infiltration events, are the dominant processes that determine infiltration water isotopic composition. We test this hypothesis using a soil moisture balance and isotope model. Our research reports, for the first time, the potential role of sub-surface evaporation in altering drip water isotopic composition, and its implications for the interpretation of speleothem δ O 18 records from arid and semi-arid regions.