DOI: 10.1038/s41561-020-0568-3
论文题名: Rapid crystallization of precious-metal-mineralized layers in mafic magmatic systems
作者: Hepworth L.N. ; Daly J.S. ; Gertisser R. ; Johnson C.G. ; Emeleus C.H. ; O’Driscoll B.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2020
卷: 13, 期: 5 起始页码: 375
结束页码: 381
语种: 英语
英文关键词: clinopyroxene
; crystallization
; layered intrusion
; magma chamber
; mineralization
; Paleogene
; percolation
; plagioclase
; platinum group element
; strontium isotope
; Scotland
; United Kingdom
英文摘要: The solidified remnants of mafic magmatic systems host the greatest concentrations of platinum-group metals in the Earth’s crust. Our understanding of precious-metal mineralization in these intrusive bodies is underpinned by a traditional view of magma chamber processes and crystal mush solidification. However, considerable uncertainty remains regarding the physical and temporal controls on concentrating these critical metals, despite their importance to modern society. We present high-precision 87Sr/86Sr analyses of plagioclase and clinopyroxene from within centimetre-thick precious-metal-enriched layers in the Palaeogene open-system Rum layered intrusion (northwest Scotland). Isotopic heterogeneity is present between plagioclase crystals, between clinopyroxene and plagioclase and within plagioclase crystals throughout the studied section. On the basis of these observations, we demonstrate that platinum-group element mineralization formed by repeated small-volume reactive melt percolation events. The preservation of strontium isotope heterogeneities at 10–100 µm length scales implies cooling of the melts that formed the precious-metal-rich layers occurred at rates greater than 1 °C per year, and cooling to diffusive closure within tens to hundreds of years. Our data highlight the importance of cyclic dissolution–recrystallization events within the crystal mush and raise the prospect that precious-metal-bearing mafic intrusions may form by repeated self-intrusion during cooling and solidification. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169609
Appears in Collections: 气候变化与战略
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作者单位: School of Geography, Geology and the Environment, Keele University, Keele, United Kingdom; Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom; UCD School of Earth Sciences, University College Dublin, Dublin, Ireland; Irish Centre for Research in Applied Geosciences, Dublin, Ireland; Department of Mathematics, University of Manchester, Manchester, United Kingdom; Department of Earth Sciences, Durham University, Durham, United Kingdom
Recommended Citation:
Hepworth L.N.,Daly J.S.,Gertisser R.,et al. Rapid crystallization of precious-metal-mineralized layers in mafic magmatic systems[J]. Nature Geoscience,2020-01-01,13(5)