Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1073/pnas.2012626118 |
Convective isolation of Hadean mantle reservoirs through Archean time | |
Jonas Tusch; Carsten Münker; Eric Hasenstab; Mike Jansen; Chris S. Marien; Florian Kurzweil; Martin J. Van Kranendonk; Hugh Smithies; Wolfgang Maier; Dieter Garbe-Schönberg | |
2021-01-12 | |
发表期刊 | Proceedings of the National Academy of Science |
出版年 | 2021 |
英文摘要 | Although Earth has a convecting mantle, ancient mantle reservoirs that formed within the first 100 Ma of Earth’s history (Hadean Eon) appear to have been preserved through geologic time. Evidence for this is based on small anomalies of isotopes such as 182W, 142Nd, and 129Xe that are decay products of short-lived nuclide systems. Studies of such short-lived isotopes have typically focused on geological units with a limited age range and therefore only provide snapshots of regional mantle heterogeneities. Here we present a dataset for short-lived 182Hf−182W (half-life 9 Ma) in a comprehensive rock suite from the Pilbara Craton, Western Australia. The samples analyzed preserve a unique geological archive covering 800 Ma of Archean history. Pristine 182W signatures that directly reflect the W isotopic composition of parental sources are only preserved in unaltered mafic samples with near canonical W/Th (0.07 to 0.26). Early Paleoarchean, mafic igneous rocks from the East Pilbara Terrane display a uniform pristine µ182W excess of 12.6 ± 1.4 ppm. From ca. 3.3Ga onward, the pristine 182W signatures progressively vanish and are only preserved in younger rocks of the craton that tap stabilized ancient lithosphere. Given that the anomalous 182W signature must have formed by ca. 4.5 Ga, the mantle domain that was tapped by magmatism in the Pilbara Craton must have been convectively isolated for nearly 1.2 Ga. This finding puts lower bounds on timescale estimates for localized convective homogenization in early Earth’s interior and on the widespread emergence of plate tectonics that are both important input parameters in many physical models. |
领域 | 地球科学 |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/309061 |
专题 | 地球科学 |
推荐引用方式 GB/T 7714 | Jonas Tusch,Carsten Münker,Eric Hasenstab,et al. Convective isolation of Hadean mantle reservoirs through Archean time[J]. Proceedings of the National Academy of Science,2021. |
APA | Jonas Tusch.,Carsten Münker.,Eric Hasenstab.,Mike Jansen.,Chris S. Marien.,...&Dieter Garbe-Schönberg.(2021).Convective isolation of Hadean mantle reservoirs through Archean time.Proceedings of the National Academy of Science. |
MLA | Jonas Tusch,et al."Convective isolation of Hadean mantle reservoirs through Archean time".Proceedings of the National Academy of Science (2021). |
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