美国耶鲁大学Alcott, Lewis J.团队的一项最新研究揭示，地壳碳酸盐岩堆积是地球氧化的驱动力。相关论文于2024年4月10日发表在《自然—地球科学》杂志上。
据介绍，地球大气和海洋的氧化作用在地表环境和生命的进化中起着关键作用。人们认为，在地球历史上，氧气的增加是由限制光合作用的营养物质磷酸盐的增加，以及来自地幔和地壳的耗氧输入减少所驱动的。然而，很难评估这些过程是否可以单独解释地球的氧化历史。
研究团队建立了一个长期全球氧、磷和碳循环的理论框架，结合了大陆出现、地幔挥发物脱气以及由此导致的地壳碳酸盐岩储层规模增加的潜在轨迹。研究发现，可以充分模拟地球大气和海洋中的氧化轨迹，同时合理地重建行星温度、大气二氧化碳浓度、磷埋藏记录和碳同位素比率。
重要的是，这只有在考虑到地壳中碳酸盐岩的积累时才有可实现能，使得通过风化和脱气不断增加的碳循环率成为可能。这种碳酸盐岩堆积是地球耦合气候、营养和氧气演化模型中缺失的一个因素，对于重建地球历史和潜在的系外行星生物地球化学非常重要。
附：英文原文
Title: Crustal carbonate build-up as a driver for Earth’s oxygenation
Author: Alcott, Lewis J., Walton, Craig, Planavsky, Noah J., Shorttle, Oliver, Mills, Benjamin J. W.
Issue&Volume: 2024-04-10
Abstract: Oxygenation of Earth’s atmosphere and oceans played a pivotal role in the evolution of the surface environment and life. It is thought that the rise in oxygen over Earth’s history was driven by an increasing availability of the photosynthetic limiting nutrient phosphate combined with declining oxygen-consuming inputs from the mantle and crust. However, it has been difficult to assess whether these processes alone can explain Earth’s oxygenation history. Here we develop a theoretical framework for the long-term global oxygen, phosphorus and carbon cycles, incorporating potential trajectories for the emergence of continents, the degassing of mantle volatiles and the resulting increase in the size of the crustal carbonate reservoir. We find that we can adequately simulate the Earth’s oxygenation trajectory in both the atmosphere and oceans, alongside reasonable reconstructions of planetary temperature, atmospheric carbon dioxide concentration, phosphorus burial records and carbon isotope ratios. Importantly, this is only possible when we include the accumulation of carbonates in the crust, which permits ever-increasing carbon recycling rates through weathering and degassing. This carbonate build-up is a missing factor in models of Earth’s coupled climate, nutrient and oxygen evolution and is important for reconstructing Earth’s history and potential exoplanet biogeochemistry.
DOI: 10.1038/s41561-024-01417-1
Source: https://www.nature.com/articles/s41561-024-01417-1