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Global chemical weathering dominated by continental arcs since the mid-Palaeozoic
Nature Geoscience ( IF 18.3 ) Pub Date : 2021-08-23 , DOI: 10.1038/s41561-021-00806-0
Thomas M. Gernon 1 , Thea K. Hincks 1 , Eelco J. Rohling 1, 2 , Martin R. Palmer 1 , Gavin L. Foster 1 , Andrew S. Merdith 3, 4 , Clément P. Bataille 5 , R. Dietmar Müller 6
Affiliation  

Earth’s plate-tectonic activity regulates the carbon cycle and, hence, climate, via volcanic outgassing and silicate-rock weathering. Mountain building, arc–continent collisions and clustering of continents in the tropics have all been invoked as controlling the weathering flux, with arcs also acting as a major contributor of carbon dioxide to the atmosphere. However, these processes have largely been considered in isolation when in reality they are all tightly coupled. To properly account for interactions among these processes, and the inherent multi-million-year time lags at play in the Earth system, we need to characterize their complex interdependencies. Here we analyse these interdependencies over the past 400 million years using a Bayesian network to identify primary relationships, time lags and drivers of the global chemical weathering signal. We find that the length of continental volcanic arcs—the fastest-eroding surface features on Earth—exerts the strongest control on global chemical weathering fluxes. We propose that the rapid drawdown of carbon dioxide tied to arc weathering stabilizes surface temperatures over geological time, contrary to the widely held view that this stability is achieved mainly by a delicate balance between weathering of the seafloor and the continental interiors.



中文翻译:

中古生代以来以大陆弧为主的全球化学风化作用

地球的板块构造活动通过火山脱气和硅酸盐岩石风化来调节碳循环,从而调节气候。造山、弧形大陆碰撞和热带大陆的聚集都被用来控制风化通量,弧形也是大气中二氧化碳的主要贡献者。然而,这些过程在很大程度上被孤立地考虑,而实际上它们都是紧密耦合的。为了正确解释这些过程之间的相互作用,以及地球系统中固有的数百万年的时间滞后,我们需要描述它们复杂的相互依赖性。在这里,我们使用贝叶斯网络分析过去 4 亿年的这些相互依赖关系,以确定主要关系,全球化学风化信号的时间滞后和驱动因素。我们发现大陆火山弧的长度——地球上侵蚀速度最快的地表特征——对全球化学风化通量施加最强的控制。我们提出,与弧风化有关的二氧化碳的快速下降可以在地质时期稳定地表温度,这与普遍认为的这种稳定性主要是通过海底风化和大陆内部之间的微妙平衡来实现的观点相反。

更新日期:2021-08-23
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