DOI: 10.1016/j.tecto.2020.228574
论文题名: Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications
作者: Autio U.A. ; Smirnov M.Y. ; Smirnova M. ; Bauer T.E. ; Korja T.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 794 语种: 英语
英文关键词: Magnetotellurics
; Sulfur compounds
; Tectonics
; Conductivity models
; Fennoscandian Shields
; Geoelectric structures
; Metasedimentary rocks
; Principal directions
; Seismic reflections
; Tectonic evolution
; Tectonic implications
; Tensors
; geoelectric field
; graphite
; magnetotelluric method
; metasedimentary rock
; Proterozoic
; tectonic evolution
; tectonic setting
; three-dimensional modeling
; Baltic Shield
; East European Craton
英文摘要: The northern part of the Fennoscandian shield records several Palaeoproterozoic phases of rifting, crustal shortening, metamorphism and structural reactivation. The geologic history has left behind a complex crustal geoelectric structure as evidenced by magnetotelluric (MT) data from the central Finnish Lapland acquired in the context of the MaSca-project in 2014. The data are characterized by strong 3-D effects such as high phase tensor skew values and anomalous induction vectors. Interestingly, however, at the same time a dominant E-W principal direction from the phase tensor data can be inferred. 3-D conductivity models derived using the ModEM code display high crustal conductance (> 10,000 S) in the vicinity of the Central Lapland Greenstone Belt, the Peräpohja Belt and the Kuusamo Belt. Conductors in the northern and southern part of the study area are separated by a resistor coinciding with the Central Lapland Granitoid Complex. A remarkable feature is an arc-shaped conductor inside the northern part of the Central Lapland Granitoid Complex, which continues into the Central Lapland Greenstone Belt in the north. The conductor is associated with a major induction vector anomaly and also coincides with extreme responses (negative phase tensor principal values), which are discussed in an accompanying paper. The conductive structures in the models are interpreted as deeply buried graphite and sulphide bearing metasedimentary rocks or as reactivated Archaean shear zones. The revealed geoelectric structures also partly correlate with seismic reflection and other geophysical data from the area. A possible explanation for the observed pervasive E-W principal direction of the phase tensor data could be the aulacogen (failed rift) suggested in recent tectonic evolution models. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170544
Appears in Collections: 气候变化与战略
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作者单位: Oulu Mining School, University of Oulu, P.O. Box 3000, Oulu, FI-90014, Finland; Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, 971 87, Sweden; Institute of Geophysics and Meteorology, University of Cologne, Pohligstrasse 3, Cologne, 50969, Germany
Recommended Citation:
Autio U.A.,Smirnov M.Y.,Smirnova M.,et al. Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications[J]. Tectonophysics,2020-01-01,794