Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1073/pnas.2020680118 |
Tungsten-182 evidence for an ancient kimberlite source | |
Nao Nakanishi; Andrea Giuliani; Richard W. Carlson; Mary F. Horan; Jon Woodhead; D. Graham Pearson; Richard J. Walker | |
2021-06-08 | |
发表期刊 | Proceedings of the National Academy of Science |
出版年 | 2021 |
英文摘要 | Globally distributed kimberlites with broadly chondritic initial 143Nd-176Hf isotopic systematics may be derived from a chemically homogenous, relatively primitive mantle source that remained isolated from the convecting mantle for much of the Earth’s history. To assess whether this putative reservoir may have preserved remnants of an early Earth process, we report 182W/184W and 142Nd/144Nd data for “primitive” kimberlites from 10 localities worldwide, ranging in age from 1,153 to 89 Ma. Most are characterized by homogeneous μ182W and μ142Nd values averaging −5.9 ± 3.6 ppm (2SD, n = 13) and +2.7 ± 2.9 ppm (2SD, n = 6), respectively. The remarkably uniform yet modestly negative μ182W values, coupled with chondritic to slightly suprachondritic initial 143Nd/144Nd and 176Hf/177Hf ratios over a span of nearly 1,000 Mya, provides permissive evidence that these kimberlites were derived from one or more long-lived, early formed mantle reservoirs. Possible causes for negative μ182W values among these kimberlites include the transfer of W with low μ182W from the core to the mantle source reservoir(s), creation of the source reservoir(s) as a result of early silicate fractionation, or an overabundance of late-accreted materials in the source reservoir(s). By contrast, two younger kimberlites emplaced at 72 and 52 Ma and characterized by distinctly subchondritic initial 176Hf/177Hf and 143Nd/144Nd have μ182W values consistent with the modern upper mantle. These isotopic compositions may reflect contamination of the ancient kimberlite source by recycled crustal components with μ182W ≥ 0. |
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/329820 |
专题 | 地球科学 |
推荐引用方式 GB/T 7714 | Nao Nakanishi,Andrea Giuliani,Richard W. Carlson,et al. Tungsten-182 evidence for an ancient kimberlite source[J]. Proceedings of the National Academy of Science,2021. |
APA | Nao Nakanishi.,Andrea Giuliani.,Richard W. Carlson.,Mary F. Horan.,Jon Woodhead.,...&Richard J. Walker.(2021).Tungsten-182 evidence for an ancient kimberlite source.Proceedings of the National Academy of Science. |
MLA | Nao Nakanishi,et al."Tungsten-182 evidence for an ancient kimberlite source".Proceedings of the National Academy of Science (2021). |
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