Bufe Aaron, Rugenstein Jeremy K C, Hovius Niels
Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany.
Department of Geosciences, Colorado State University, Fort Collins, CO 80523, USA.
Science. 2024 Mar 8;383(6687):1075-1080. doi: 10.1126/science.adk0957. Epub 2024 Mar 7.
Uplift and erosion modulate the carbon cycle over geologic timescales by exposing minerals to chemical weathering. However, the erosion sensitivity of mineral weathering remains difficult to quantify. Solute-chemistry datasets from mountain streams in different orogens isolate the impact of erosion on silicate weathering-a carbon dioxide (CO) sink-and coupled sulfide and carbonate weathering-a CO source. Contrasting erosion sensitivities of these reactions produce a CO-drawdown maximum at erosion rates of ~0.07 millimeters per year. Thus, landscapes with moderate uplift rates bolster Earth's inorganic CO sink, whereas more rapid uplift decreases or even reverses CO sequestration. This concept of an "erosion optimum" for CO drawdown reconciles conflicting views on the impact of mountain building on the carbon cycle and permits estimates of geologic CO fluxes dependent upon tectonic changes.
隆升和侵蚀通过使矿物遭受化学风化作用，在地质时间尺度上调节碳循环。然而，矿物风化的侵蚀敏感性仍然难以量化。来自不同造山带山区溪流的溶质化学数据集，分离出了侵蚀对硅酸盐风化（一种二氧化碳（CO）汇）以及硫化物和碳酸盐耦合风化（一种CO源）的影响。这些反应不同的侵蚀敏感性在每年约0.07毫米的侵蚀速率下产生了最大的CO消耗。因此，中等隆升速率的地貌增强了地球的无机CO汇，而更快的隆升则减少甚至逆转了CO的封存。这种关于CO消耗的“侵蚀最优值”概念调和了关于造山运动对碳循环影响的相互矛盾的观点，并允许根据构造变化估算地质CO通量。
