دورية أكاديمية
Electron backscatter diffraction analysis combined with NanoSIMS U–Pb isotope data reveal intra-grain plastic deformation in zircon and its effects on U–Pb age: examples from Himalayan eclogites, Pakistan
| العنوان: | Electron backscatter diffraction analysis combined with NanoSIMS U–Pb isotope data reveal intra-grain plastic deformation in zircon and its effects on U–Pb age: examples from Himalayan eclogites, Pakistan |
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| المؤلفون: | H. U. Rehman, T. Kagoshima, N. Takahata, Y. Sano, F. Barou, D. Mainprice, H. Yamamoto |
| المصدر: | European Journal of Mineralogy, Vol 35, Pp 1079-1090 (2023) |
| بيانات النشر: | Copernicus Publications, 2023. |
| سنة النشر: | 2023 |
| المجموعة: | LCC:Mineralogy |
| مصطلحات موضوعية: | Mineralogy, QE351-399.2 |
| الوصف: | Zircon grains preserve records of crystallization, growth, and/or deformation that can be envisaged from their internal structures and through the U–Pb isotope analysis. Electron backscatter diffraction (EBSD) is a non-destructive method for visualizing undeformed domains to differentiate them from those that are plastically deformed. In this study, we report EBSD analyses conducted on zircon grains, in thin sections with available textural information, from Himalayan eclogites. The studied eclogite samples show no petrographic evidence of shearing or mylonitization. However, several zircon grains preserve plastically deformed domains. These deformed domains display several degrees of misorientation relative to the undeformed domain and yielded geologically reset ages when analysed for U–Pb isotope ratios using nanoscale secondary ion mass spectrometry (NanoSIMS), in contrast to most undeformed domains which retained the protolith age. The degree of resetting is positively correlated with the extent of misorientation. These pieces of evidence indicate that plastic deformation in zircon grains, equilibrated at higher pressure–temperature conditions, affected the primary geochemical and geochronological records. Based on these observations, we assume that not only regional shearing/mylonitization in metamorphic rocks affects the geochemical records, but also that zircon grains in apparently unsheared high-grade metamorphic rocks behave plastically. The micro-scale intra-grain plastically deformed domains can easily be identified through EBSD analysis in the form of crystallographic misorientations. To extract meaningful geochronological results, it is necessary to identify undisturbed domains in zircon grains before applying any destructive analytical method. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1079-2023 0935-1221 1617-4011 |
| Relation: | https://ejm.copernicus.org/articles/35/1079/2023/ejm-35-1079-2023.pdf; https://doaj.org/toc/0935-1221; https://doaj.org/toc/1617-4011 |
| DOI: | 10.5194/ejm-35-1079-2023 |
| URL الوصول: | https://doaj.org/article/6a125e95e5a34ef4979c1a0c059eac78 |
| رقم الأكسشن: | edsdoj.6a125e95e5a34ef4979c1a0c059eac78 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 10792023 09351221 16174011 |
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| DOI: | 10.5194/ejm-35-1079-2023 |