DOI: 10.1016/j.tecto.2021.228816
论文题名: Towards an understanding of mineral systems – Contributions from magnetotelluric data from the Fennoscandian Shield in northern Sweden
作者: Vadoodi R. ; Rasmussen T.M. ; Smirnov M. ; Bauer T.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 808 语种: 英语
中文关键词: 3D Inversion
; Electrical Conductivities
; Magnetotellurics
; Mineralisation
英文关键词: 3D modeling
; Magnetite
; Telluric prospecting
; Airborne magnetic data
; Crustal conductors
; Electrically conductive
; Fennoscandian Shields
; High conductivity
; Hydrothermal fluids
; Magnetotelluric data
; Spatial resolution
; Magnetotellurics
; Archean
; boundary condition
; data inversion
; data processing
; electrical conductivity
; magnetotelluric method
; mineral exploration
; mineralization
; Precambrian
; spatial resolution
; three-dimensional modeling
; Baltic Shield
; East European Craton
; Sweden
英文摘要: Magnetotelluric data from 104 new stations in northern Sweden together with previously available MaSca project data are analysed with respect to a hypothesised genetic relation between mineral occurrences and commonly reported deep crustal electrically conductive structures in Precambrian Shield areas. A total of 165 stations from the north-eastern part of the Norrbotten ore province are modelled from an area characterised as having an Archaean basement with later reworking during the Paleoproterozoic. The data cover an area of 200 × 250 km2 and provide a significant improvement of spatial resolution compared to previously available data. The derived 3D model reveals the presence of strong crustal conductors with conductance of more than 3000 S at depth of tens of kilometres within a generally resistive crust. A subdivision into a central more conductive domain bounded towards north and south by resistive domains is revealed. The boundaries between these three domains are oriented NW-SE. The southern boundary coincides roughly with the boundary between Archaean and Paleoproterozoic crust defined by εNd data. The northern boundary coincides with an interpreted 2.4–2.3 Ga coastline of a marine rift basin, which is spatially defined by the occurrence of the Kovo group rocks. The location of major conductors within the central domain correlates with the presence of mapped Paleoproterozoic metasupracrustal belts. A significant part of the middle crust conductors is elongated in directions that coincide with major deformation zones that have been mapped from airborne magnetic data and geological fieldwork. Some of these conductors have near-surface expression where they spatially correlate with the location of known mineralisation. In these cases, the conductive structures may mark the pathways for metal-bearing hydrothermal fluids. Interpretations involving enhanced quantities of magnetite or graphite in the middle crust are discussed but the magnetotelluric data alone are not conclusive with respect to cause of observed high conductivities. © 2021 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170914
Appears in Collections: 气候变化与战略
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作者单位: Geosciences and Environmental Engineering, Dept. of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, SE-971 87, Sweden
Recommended Citation:
Vadoodi R.,Rasmussen T.M.,Smirnov M.,et al. Towards an understanding of mineral systems – Contributions from magnetotelluric data from the Fennoscandian Shield in northern Sweden[J]. Tectonophysics,2021-01-01,808