Dominance of felsic continental crust on Earth after 3 billion years ago is recorded by vanadium isotopes

作者：Shengyu Tian, Xin Ding, Yuhan Qi, Fei Wu, Yue Cai, Richard M. Gaschnig, Zicong Xiao, Wei‐Xin Lv, Roberta L. Rudnick, Fang Huang · 发表于：Proceedings of the National Academy of Sciences · 年份：2023 · DOI：10.1073/pnas.2220563120 · 被引用次数：31 · 研究领域：Geological and Geochemical Analysis、Geochemistry and Elemental Analysis、Paleontology and Stratigraphy of Fossils

The transition from mafic to felsic upper continental crust (UCC) is crucial to habitability of Earth, and may be related to the onset of plate tectonics. Thus, defining when this crustal transition occurred has great significance for the evolution of Earth and its inhabitants. We demonstrate that V isotope ratios (reported as δ 51 V) provide insights into this transition because they correlate positively with SiO 2 and negatively with MgO contents during igneous differentiation in both subduction zones and intraplate settings. Because δ 51 V is not affected by chemical weathering and fluid–rock interactions, δ 51 V of the fine-grained matrix of Archean to Paleozoic (3 to 0.3 Ga) glacial diamictite composites, which sample the UCC at the time of glaciation, reflect the chemical composition of the UCC through time. The δ 51 V values of glacial diamictites systematically increase with time, indicating a dominantly mafic UCC at ~3 Ga; the UCC was dominated by felsic rocks only after 3 Ga, coinciding with widespread continental emergence and many independent estimates for the onset of plate tectonics.