Tusch Jonas, Hoffmann J Elis, Hasenstab Eric, Fischer-Gödde Mario, Marien Chris S, Wilson Allan H, Münker Carsten
Institut für Geologie und Mineralogie, Universität zu Köln, 50674 Köln, Germany.
Institut für Geologische Wissenschaften, Freie Universität Berlin, 12249 Berlin, Germany.
Proc Natl Acad Sci U S A. 2022 May 3;119(18):e2120241119. doi: 10.1073/pnas.2120241119. Epub 2022 Apr 22.
SignificanceDue to active plate tectonics, there are no direct rock archives covering the first ca. 500 million y of Earth's history. Therefore, insights into Hadean geodynamics rely on indirect observations from geochemistry. We present a high-precision W dataset for rocks from the Kaapvaal Craton, southern Africa, revealing the presence of Hadean protocrustal remnants in Earth's mantle. This has broad implications for geochemists, geophysicists, and modelers, as it bridges contrasting W isotope patterns in Archean and modern mantle-derived rocks. The data reveal the origin of seismically and isotopically anomalous domains in the deep mantle and also provide firm evidence for the operation of silicate differentiation processes during the first 60 million y of Earth's history.
重要性
由于板块构造活动活跃，没有直接的岩石档案覆盖地球历史最初约5亿年的时间。因此，对冥古宙地球动力学的认识依赖于地球化学的间接观测。我们展示了来自南非卡普瓦尔克拉通岩石的高精度钨数据集，揭示了地球地幔中冥古宙原生地壳残余物的存在。这对地球化学家、地球物理学家和建模人员具有广泛影响，因为它弥合了太古宙和现代地幔衍生岩石中截然不同的钨同位素模式。这些数据揭示了下地幔中地震和同位素异常区域的起源，也为地球历史最初6000万年期间硅酸盐分异过程的运作提供了确凿证据。
