Mineral weathering plays a primary role in the geologic carbon cycle. Silicate weathering by carbonic acid consumes CO2 and stabilizes Earth's climate system. However, when sulfuric acid drives weathering, CO2 can be released to the atmosphere. Recent work has established that sulfuric acid weathering resulting from sulfide mineral oxidation is globally significant and particularly important in rapidly eroding environments. In contrast, if SO42− produced by sulfide oxidation is reduced during continental transit, then CO2 release may be negated. Yet, little is known about how much SO42− reduction takes place in terrestrial environments. We report oxygen and sulfur stable isotope ratios of SO42− in river waters and mass budget calculations, which together suggest that SO42− released from pyrite oxidation in the Peruvian Andes mountains is conservatively exported across ∼300 km of the Amazon floodplain. In this system, floodplain SO42− reduction does not counteract the large SO42− flux from Andean pyrite weathering or measurably affect the stable isotope composition of riverine SO42−. These findings support the hypothesis that uplift and erosion of sedimentary rocks drive release of CO2 from the rock reservoir to the atmosphere.

中文翻译：

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溶解硫酸盐在秘鲁 Rio Madre de Dios 洪泛区的保守输送

矿物风化在地质碳循环中起主要作用。由碳酸风化的硅酸盐消耗二氧化碳并稳定地球的气候系统。然而，当硫酸推动风化时，二氧化碳会释放到大气中。最近的工作已经确定，硫化物矿物氧化导致的硫酸风化在全球范围内具有重要意义，并且在快速侵蚀的环境中尤为重要。相反，如果在大陆运输过程中硫化物氧化产生的 SO42− 被减少，那么 CO2 的释放可能会被抵消。然而，对于在陆地环境中发生了多少 SO42− 减少，我们知之甚少。我们报告了河水中 SO42− 的氧和硫稳定同位素比率和质量预算计算，这表明秘鲁安第斯山脉黄铁矿氧化释放的 SO42− 被保守地输出到约 300 公里的亚马逊洪泛区。在该系统中，洪泛区 SO42- 减少不会抵消安第斯黄铁矿风化产生的大量 SO42- 通量，也不会显着影响河流 SO42- 的稳定同位素组成。这些发现支持沉积岩的隆起和侵蚀驱动二氧化碳从岩石储层释放到大气的假设。