Evaporite weathering and deposition as a long-term climate forcing mechanism
Evaporite weathering and deposition as a long-term climate forcing mechanism
复制标题
蒸发岩风化和沉积作为长期气候强迫机制
作者：
G. Shields;Benjamin J. W. Mills
虽然人们普遍认为，地球的长期表面温度是由硅酸盐风化和气候对CO2的相互依赖调节的，但一些气候事件的根本原因仍未得到解决。我们在这里首次展示了蒸发岩风化和沉积之间的不平衡可以通过碳酸盐沉积过程影响气候。硫酸钙风化作用在没有碳酸盐碱度的情况下向海洋提供Ca2+离子，因此碳酸盐降水的增加通过将二氧化碳转移到大气中而加强了温室效应。相反，硫酸钙沉积减弱了温室效应，而蒸发岩巨体的高沉积速率可能会压倒硅酸盐风化反馈，导致数度的行星冷却。非稳态蒸发岩动力学和相关反馈作为长期碳循环变化的驱动因素迄今一直被忽视。在这里，我们说明了蒸发岩沉积的重要性，特别是通过展示一系列大规模沉积事件如何在中新世中晚期导致全球变冷。
Although it is widely accepted that Earth’s long-term surface temperature is regulated by the mutual dependence of silicate weathering and climate on CO2, the root causes of some climatic events remain unresolved. We show here for the first time that imbalances between evaporite weathering and deposition can affect climate through the process of carbonate sedimentation. Calcium sulfate weathering supplies Ca2+ ions to the ocean unaccompanied by carbonate alkalinity, so that increased carbonate precipitation strengthens greenhouse forcing through transfer of CO2 to the atmosphere. Conversely, calcium sulfate deposition weakens greenhouse forcing, while the high depositional rates of evaporite giants may overwhelm the silicate weathering feedback, causing several degrees of planetary cooling. Non-steady-state evaporite dynamics and related feedbacks have hitherto been overlooked as drivers of long-term carbon cycle change. Here, we illustrate the importance of evaporite deposition, in particular, by showing how a series of massive depositional events contributed to global cooling during the mid–late Miocene.
影响因子：
5
作者：
R. Zeebe;T. Tyrrell
通讯作者：
R. Zeebe;T. Tyrrell