Department of Earth & Environmental Sciences, University of Rochester, Rochester, NY, 14627, USA.
School of Earth and Environmental Sciences, University of St Andrews, Bute Building, St Andrews, Scotland, KY16 9TS, UK.
Nat Commun. 2023 Feb 28;14(1):1140. doi: 10.1038/s41467-023-36538-5.
Constraining the lithological diversity and tectonics of the earliest Earth is critical to understanding our planet's evolution. Here we use detrital Jack Hills zircon (3.7 - 4.2 Ga) analyses coupled with new experimental partitioning data to model the silica content, Si+O isotopic composition, and trace element contents of their parent melts. Comparing our derived Jack Hills zircons' parent melt Si+O isotopic compositions (-1.92 ≤ δSi ≤ 0.53 ‰; 5.23 ≤ δO ≤ 9.00 ‰) to younger crustal lithologies, we conclude that the chemistry of the parent melts was influenced by the assimilation of terrigenous sediments, serpentinites, cherts, and silicified basalts, followed by igneous differentiation, leading to the formation of intermediate to felsic melts in the early Earth. Trace element measurements also show that the formational regime had an arc-like chemistry, implying the presence of mobile-lid tectonics in the Hadean. Finally, we propose that these continental-crust forming processes operated uniformly from 4.2 to at least 3.7 Ga.
约束最古老地球的岩石多样性和构造对于理解我们行星的演化至关重要。在这里，我们使用碎屑杰克山锆石（37-42 亿年）分析，并结合新的实验分配数据来模拟其母熔体的硅含量、Si+O 同位素组成和微量元素含量。将我们推导的杰克山锆石的母熔体 Si+O 同位素组成（-1.92≤δSi≤0.53‰；5.23≤δO≤9.00‰）与年轻的地壳岩石进行比较，我们得出结论，母熔体的化学性质受到陆源沉积物、蛇纹岩、硅质岩和硅化玄武岩的同化，以及随后的火成分异的影响，导致在早期地球中形成中等到长英质熔体。微量元素测量也表明，形成体系具有弧状化学性质，暗示在冥古宙存在活动陆壳构造。最后，我们提出这些大陆地壳形成过程在 42 亿至至少 37 亿年前均匀地进行。
