Argon constraints on the early growth of felsic continental crust
Argon constraints on the early growth of felsic continental crust
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DOI：
10.1126/sciadv.aaz6234
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发表时间：
2020-05-01
期刊：
影响因子：
13.6
通讯作者：
Korenaga, Jun
中科院分区：
文献类型：
--
作者：
Guo, Meng;Korenaga, Jun
大陆地壳是主要的地球化学库，其演化塑造了地球的表面环境。在这项研究中，我们提出了一种新的地壳-地幔-大气耦合演化模型，用大气 Ar-40/Ar-36 约束大陆地壳的生长。我们的模型是第一个以自洽方式将氩气脱气与地球热演化结合起来的模型，并利用地壳形成和表面年龄的分布纳入地壳循环和再加工的影响。我们的结果表明，氩气脱气的历史有利于地球早期地壳的快速生长。据估计，早太古代时期，富含钾的大陆地壳质量已达到当今水平的 80% 以上。这种富含钾的、可能是长英质的地壳的存在对于早期地球的构造、地表环境和地幔对流状况具有重要意义。
The continental crust is a major geochemical reservoir, the evolution of which has shaped the surface environment of Earth. In this study, we present a new model of coupled crust-mantle-atmosphere evolution to constrain the growth of continental crust with atmospheric Ar-40/Ar-36. Our model is the first to combine argon degassing with the thermal evolution of Earth in a self-consistent manner and to incorporate the effect of crustal recycling and reworking using the distributions of crustal formation and surface ages. Our results suggest that the history of argon degassing favors rapid crustal growth during the early Earth. The mass of continental crust, highly enriched in potassium, is estimated to have already reached >80% of the present-day level during the early Archean. The presence of such potassium-rich, likely felsic, crust has important implications for tectonics, surface environment, and the regime of mantle convection in the early Earth.