中国科学院地质与地球物理研究所Changle Wang等人报道，太古宙的带状铁地层中记录了大陆风化的开始。相关论文于2024年12月12日发表于国际顶尖学术期刊《地质学》杂志上。

据介绍，早期陆块的出现通过大陆风化提供营养物质，影响了海洋化学和生物圈的演化。然而，关于早期大陆风化作用的出现时间和开始时间仍然存在不确定性。

研究人员提供了条带状铁矿（BIFs）中锗（Ge）和硅（Si）的汇编，以评估太古宙风化。利用BIFs中Ge/Si比值与Si含量的负相关关系，研究首次插值了太古代海水Ge/Si的演化。

数据分析揭示了Ge/Si的逐步下降，从接近热液值到类似大陆输入值，约为ca.3.5Ga。基于Ge-Si质量平衡模型，研究人员认为，这种转变是由于河流通量的增加，与大陆地壳的迅速出现相一致。

值得注意的是，这意味着太古代早期满足了海洋生物圈形成的两个关键先决条件：(1)存在适合底栖生物和浮游生物群落生存的边缘海洋环境；以及(2)提供来自陆地的营养供应。

附：英文原文

Title: The onset of continental weathering recorded in Archean banded iron formations

Author: Changle Wang, Leslie J. Robbins, Zidong Peng, Lianchang Zhang, Bo Wan, Kurt O. Konhauser

Issue&Volume: 2024-12-12

Abstract: Early landmass emergence impacted marine chemistry and biosphere evolution by supplying nutrients through continental weathering. However, uncertainties persist regarding the timing of emergence and onset of early continental weathering. We present a compilation of germanium (Ge) and silicon (Si) in banded iron formations (BIFs) to assess Archean weathering. By leveraging the inverse correlation between Ge/Si ratios and Si contents in BIFs, we interpolate the evolution of Archean seawater Ge/Si for the first time. Our analyses reveal a stepwise decrease in Ge/Si, from near-hydrothermal values to those resembling continental input, at ca. 3.5 Ga. Based on a Ge-Si mass balance model, we propose that this shift is attributable to increased riverine fluxes, coinciding with the rapid emergence of continental crust. Significantly, this implies that two crucial prerequisites for the establishment of a marine biosphere were fulfilled in the early Archean: (1) the presence of marginal marine environments suitable for benthic and planktonic communities; and (2) a supply of terrestrially sourced nutrients.

DOI: 10.1130/G52793.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52793.1/650648/The-onset-of-continental-weathering-recorded-inredirectedFrom=fulltext