| DOI: | 10.1016/j.tecto.2021.228982
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| 论文题名: | A crustal magnetic model of Britain obtained by 3D inversion |
| 作者: | Beamish D.; Pharaoh T.C.; Schofield D.I.
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| 刊名: | Tectonophysics
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| ISSN: | 00401951
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| 出版年: | 2021
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| 卷: | 814 | | 语种: | 英语
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| 中文关键词: | 3D inversion
; British tectonic terranes
; Crustal scale
; Magnetic anomalies
; Subduction zone processes
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| 英文关键词: | Lithology
; Magnetic storage
; Magnetism
; Tectonics
; Aeromagnetic surveys
; Degree of fidelity
; Imprecise knowledge
; Inversion procedure
; Magnetic modeling
; Oceanic lithosphere
; Profile inversion
; Structural insights
; 3D modeling
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| 英文摘要: | The national baseline aeromagnetic survey of Britain allows a uniform assessment of the shallow and deep magnetic properties of the British tectonic terranes. The most significant is that associated with destruction of early Palaeozoic oceanic lithosphere across the Iapetus Suture separating Baltica and Avalonia from the Laurentian terranes. Here a formal 3D inversion of a continuous swathe of the data is considered. The study provides a uniform volumetric whole crust assessment extending for over 1000 km. Normally a 3D inversion of magnetic data is controlled using a variety of constraints however this is not appropriate at the crustal scale due to our increasingly imprecise knowledge of lithology at increasingly greater depths. The main crustal interface encountered occurs at the Curie isotherm depth. We demonstrate the behaviour of introducing different magnetic crustal depths and suggest the crustal ‘magnetic depth’ of our models can be independently constrained using global or regional studies of the deep geotherm. Static magnetic data have no inherent depth resolution. Here an empirical ‘1D depth’ weighting and a more formal ‘3D distance’ weighting are assessed. The inversion procedure is regularised to provide stable models appropriate to the data and their errors. To gain confidence when using such a ‘geologically-unconstrained’ inversion, we compare our 3D inversion results with an existing geologically-constrained 2.5D profile inversion across northern Britain. A surprising agreement in the 3D susceptibility magnitudes is observed. The chosen study area traverses 10 British terranes and images their tectonic fabric by way of non-magnetic zones (i.e. susceptibilities <0.0001 to 0.001 SI) and magnetic zones displaying geological relevance and tectonic significance at deeper crustal levels. Here we discuss the more significant 3D model features which, by virtue of a continuous crustal-scale assessment and fitting the data with a high degree of fidelity, provide additional structural insights. © 2021 British Geological Survey, a component body of UKRI (BGS (c) UKRI ALL RIGHTS RESERVED |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/170777
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| Appears in Collections: | 气候变化与战略
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作者单位: | British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom
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| Recommended Citation: | |
Beamish D.,Pharaoh T.C.,Schofield D.I.. A crustal magnetic model of Britain obtained by 3D inversion[J]. Tectonophysics,2021-01-01,814
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