从碳源到碳汇：大陆弧演化过程中岩浆与剥蚀作用对长期碳循环的影响

在百万年时间尺度上，大气、海洋中的二氧化碳浓度(P_CO2,二氧化碳分压)和长期变化主要受岩浆-变质脱碳作用和硅酸盐风化作用(消耗二氧化碳)控制。因此，地球表层主要构造活动带的构造-岩浆活动对长期碳循环具有重要的驱动作用。本文在总结已发表文献的基础上，系统评估了大陆弧，尤其是晚白垩世大陆弧的岩浆作用和剥蚀作用的碳通量，并以此为依据探讨了大陆弧演化对于全球长期碳循环的影响。大陆弧岩浆作用以周期性(几十万年至一百百万年)岩浆爆发(magmatic flare-ups)为特征。在一个周期内，大规模岩浆喷发会导致CO₂排放量大幅度增加，促进温室效应。但同时，大规模的岩浆作用又会导致地壳增厚和和地表抬升，从而促进剥蚀作用、提高化学风化通量，进而增加CO₂消耗量。对于单个的大陆弧来说，在其演化的不同阶段对于碳循环扮演着不同的角色：演化早期由于岩浆作用起主导作用，表现为净碳源；而在岩浆作用减弱或停止后，由于剥蚀作用的持续进行，表现为净碳汇。因此，从长周期和全球尺度上讲，大陆弧岩浆活动表现的“碳源属性”受到化学风化作...

From carbon source to carbon sink:Influences of magmatism and erosion in continental arcs on long-term carbon cycle

On multimillion-year time scales, the long-term stability of atmospheric-oceanic P_CO2 is dominantly determined by the balance between the rate of CO₂ input from magmatic/metamorphic degassing and the efficiency of CO₂ uptake by silicate weathering. Continental arcs are characterized by episodic voluminous magmatic flare-ups in the time scale of tens to hundreds of millions of years. Flare-ups in continental arc result in increasing CO₂ outgassing, which enhances CO₂ concentration in the atmosphere and greenhouse climate. However, development of continental magmatic arc often accompanies with rapid arc unroofing and erosion due to magmatic/tectonic thickening of the crust, thus also enhances the chemical weathering flux, which in turn increases the CO₂ sink. With the coupled magmatism and erosion processes in continental arcs, during the rise and fall and continental arcs, regionally the arc serves as either a carbon source or sink depending on the stage of the arc life. The development of continental arcs increases weatherability through mountain building processes, and therefore may increase the strength of the global negative feedback between silicate weathering and climate. In this way continental arcs play an important role in sustaining the Earth habitability.