Snowball Earth at low solar luminosity prevented by the oceanatmosphere coupling

作     者：Ruimin Wang Bing Shen 

作者机构：Key Laboratory of Orogenic Belts and Crustal EvolutionMOE School of Earth and Space Science Peking University 

出 版 物：《Acta Geochimica》 (地球化学学报（英文）)

年 卷 期：2019年第38卷第6期

页      面：775-784页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 

基　　金：supported by the National Natural Science Foundation of China (Grant Number 41772359) 

主　　题：Faint Young Sun paradox Carbon dioxide Earth system Siderite 

摘      要：The standard solar model proposes that the solar luminosity was 30%lower than the present level at 4.5 billion years ago(Ga).At low solar radiation,the climate model predicts that the Earth should have been completely covered by ice in the first 2 billion years,*** the snowball Earth climate mode,when the atmospheric CO2 content was at the present ***,snowball Earth condition is inconsistent with various sedimentological,paleontological,and geochemical *** controversy is collectively known as the Taint Young Sun,(FYS)*** various models have been proposed,the FYS paradox has not yet been *** this study,we develop a model by considering the ocean-atmosphere coupling to show that high atmospheric CO2 level could be sustained at low seawater *** modeling result indicates that 0.1 bar atmospheric CO2 level that was required to prevent snowball Earth in early Archean could be sustained at seawater pH of *** the absence of siderite in Archean paleosols has been used to argue against high atmospheric CO2 level,we suggest that siderite precipitation in paleosols was not controlled by the atmospheric CO2 level ***,siderite could precipitate in anoxic conditions with various amount of CO2 in the atmosphere,suggesting siderite cannot be used to reconstruct the atmospheric CO2 ***,the new model suggests that the snowball Earth condition could be prevented by the coupling of atmosphere and ocean systems,and thus the emergence of the ocean in the very beginning of Earth evolution might be the key to the subsequence evolution of habitability.