近日，加拿大卡尔加里大学Benjamin M. Tutolo团队研究了陆地岩石风化后二氧化碳、钙和镁的命运。相关论文于2025年8月20日发表在《地质学》杂志上。

硅酸盐碳酸盐循环控制着大气中的二氧化碳浓度，并在地质时间尺度上缓和地球气候。硅酸盐矿物受CO₂的化学风化作用导致阳离子的释放，并使CO₂中和为HCO₃^-还是CO₃^2-。一旦水过饱和，预计会有碳酸钙和碳酸镁矿物的沉淀。然而，量化所需的过饱和程度，特别是镁碳酸盐，仍然具有挑战性。

研究组提供了一个来自加拿大不列颠哥伦比亚省中央高原的854个水样的数据库，代表了广泛的盐度，包括Na−(SO₄)−HCO₃−CO₃和Mg-Na-SO₄高盐湖，以确定碳酸钙和碳酸镁形成的地球化学阈值。对于以HCO₃^-为主的水体，数据显示碳酸钙的最大碱度阈值为~5 mEq/kg，碳酸镁的最大碱度阈值为~40 mEq/kg。

CaCO₃^2-活性图和MgCO₃^2-碳酸钙和碳酸镁的最大饱和阈值均适用于HCO₃为主、SO₄为主和富含CO₂的水体。这些地球化学阈值可能以优化地球化学二氧化碳去除（geoCDR）技术为主题，例如增强岩石风化，如HCO₃^-是碳酸盐矿物CDR效率的两倍。

附：英文原文

Title: The fate of CO2, Ca, and Mg after terrestrial rock weathering

Author: Maija J. Raudsepp, Sasha Wilson, Benjamin M. Tutolo

Issue&Volume: 2025-08-20

Abstract: The silicatecarbonate cycle controls atmospheric CO2 concentrations and moderates Earth’s climate over geologic time scales. Chemical weathering of silicate minerals by CO2 results in the release of cations and the neutralization of CO2 to HCO3 or CO32. The precipitation of Ca- and Mg-carbonate minerals is expected once waters are supersaturated. However, quantifying the magnitude of supersaturation required, particularly for Mg-carbonates, has remained challenging. Here we present a database of 854 water samples from the Central Plateau, British Columbia, Canada, representing a wide range of salinities, including both Na(SO4)HCO3CO3 and MgNaSO4 hypersaline lakes, to determine the geochemical thresholds for Ca- and Mg-carbonate formation. For HCO3-dominated waters, the data indicate maximum alkalinity thresholds of ～5 mEq/kg for Ca-carbonates and ～40 mEq/kg for Mg-carbonates. Activity plots of CaCO32 and MgCO32 suggest that maximum saturation thresholds for both Ca-carbonates and Mg-carbonates are applicable to HCO3-dominated, SO4-dominated, and CO2-rich waters. These geochemical thresholds may be used to optimize geochemical carbon dioxide removal (geoCDR) technologies, such as enhanced rock weathering, as HCO3 has up to double the CDR efficiency of carbonate minerals.

DOI: 10.1130/G53354.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G53354.1/660703/The-fate-of-CO2-Ca-and-Mg-after-terrestrial-rock