德国地球科学研究中心Hovius, Niels研究团队，报道了地球动力学对亚平宁中部深层二氧化碳释放和碳收支的调节。相关论文发表在2024年4月19日出版的《自然—地球科学》杂志上。
研究小组分析了意大利亚平宁山脉中部河流的水化学成分，这些河流在相对恒定的气候条件下跨越了热流和熔岩厚度的梯度。研究人员量化了近地表风化作用、变质作用和碳酸盐熔融过程中无机碳通量的平衡。课题组人员发现，在区域尺度上，在以热流大于150mw m-2为特征的俯冲板块撕裂上，来自熔融岩层的碳排放超过近地表通量两个数量级。
相比之下，风化过程主导着碳收支，当碳厚度超过40热流小于30mw m-2。变质通量的变化比风化通量的变化大一到两个数量级。因此，课题组研究人员认为变质熔融和脱碳反应的地球动力学调节，是构造调节无机碳循环的有效过程。
据介绍，最近的研究越来越多地认识到造山过程中临界带风化，对长期二氧化碳吸收和释放的重要性。然而，对近地表风化反应的关注通常不能解释陨坑的二氧化碳排放，而陨坑的二氧化碳排放可能超过，在俯冲和变质过程中碳酸盐融化和脱碳的二氧化碳减少。
附：英文原文
Title: Deep CO2 release and the carbon budget of the central Apennines modulated by geodynamics
Author: Erlanger, Erica, Bufe, Aaron, Paris, Guillaume, DAngeli, Ilenia, Pisani, Luca, Kemeny, Preston Cosslett, Stammeier, Jessica, Haghipour, Negar, Hovius, Niels
Issue&Volume: 2024-04-19
Abstract: Recent studies increasingly recognize the importance of critical-zone weathering during mountain building for long-term CO2 drawdown and release. However, the focus on near-surface weathering reactions commonly does not account for CO2 emissions from the crust, which could outstrip CO2 drawdown where carbonates melt and decarbonize during subduction and metamorphism. We analyse water chemistry from streams in Italy’s central Apennines that cross a gradient in heat flow and crustal thickness with relatively constant climatic conditions. We quantify the balance of inorganic carbon fluxes from near-surface weathering processes, metamorphism and the melting of carbonates. We find that, at the regional scale, carbon emissions from crustal sources outpace near-surface fluxes by two orders of magnitude above a tear in the subducting slab characterized by heat flow greater than 150mWm–2 and crustal thickness of less than 25km. By contrast, weathering processes dominate the carbon budget where crustal thickness exceeds 40km and heat flow is lower than 30mWm–2. The observed variation in metamorphic fluxes is one to two orders of magnitude larger than that of weathering fluxes. We therefore suggest that geodynamic modulations of metamorphic melting and decarbonation reactions are an efficient process by which tectonics can regulate the inorganic carbon cycle.
DOI: 10.1038/s41561-024-01396-3
Source: https://www.nature.com/articles/s41561-024-01396-3