气候变化领域集成服务门户(CCPortal): Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications

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DOI	10.1016/j.tecto.2020.228574
	Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications
	Autio U.A.; Smirnov M.Y.; Smirnova M.; Bauer T.E.; Korja T.
发表日期	2020
ISSN	00401951
卷号	794
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.
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
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207710
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
推荐引用方式 GB/T 7714	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],2020,794.
APA	Autio U.A.,Smirnov M.Y.,Smirnova M.,Bauer T.E.,&Korja T..(2020).Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications.Tectonophysics,794.
MLA	Autio U.A.,et al."Magnetotelluric array in the central Finnish Lapland II: 3-D inversion and tectonic implications".Tectonophysics 794(2020).