Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits

The Bergslagen region is one of the most ore prospective districts in Sweden. Presented here are results from two nearly 25 km long reflection seismic profiles crossing this region in the Dannemora mining area. The interpretations are constrained by seismic wave velocity measurements on a series of...

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Main Authors: Malehmir, A., Dahlin, P., Lundberg, E., Juhlin, Christopher, Sjöström, H., Högdahl, K.
Format: Journal Article
Published: Blackwell Publishing Ltd 2011
Online Access:http://hdl.handle.net/20.500.11937/9090
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author Malehmir, A.
Dahlin, P.
Lundberg, E.
Juhlin, Christopher
Sjöström, H.
Högdahl, K.
author_facet Malehmir, A.
Dahlin, P.
Lundberg, E.
Juhlin, Christopher
Sjöström, H.
Högdahl, K.
author_sort Malehmir, A.
building Curtin Institutional Repository
collection Online Access
description The Bergslagen region is one of the most ore prospective districts in Sweden. Presented here are results from two nearly 25 km long reflection seismic profiles crossing this region in the Dannemora mining area. The interpretations are constrained by seismic wave velocity measurements on a series of rock samples, cross-dip analysis, prestack time migration, and swath 3-D imaging, as well as by other available geophysical and geological observations. A series of major fault zones is imaged by the seismic data, as is a large mafic intrusion. However, the most prominent feature is a package of east-dipping reflectors found east of the Dannemora area that extend down to at least 3 km depth. This package is associated with a polyphase, ductile-brittle deformation zone with the latest ductile movement showing east-side-up or reverse kinematics. Its total vertical displacement is estimated to be in the order of 2.5 km. Also clearly imaged in the seismic data is a steeply dipping reflector near the Dannemora mine that extends down to a depth of at least 2.2 km. The geological nature of this reflector is not known, but it could represent either a fluid-bearing fault zone or a deep-seated iron deposit, making it an important target for further detailed geophysical and geological investigations. Copyright 2011 by the American Geophysical Union.
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spelling curtin-20.500.11937-90902017-09-13T14:48:44Z Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits Malehmir, A. Dahlin, P. Lundberg, E. Juhlin, Christopher Sjöström, H. Högdahl, K. The Bergslagen region is one of the most ore prospective districts in Sweden. Presented here are results from two nearly 25 km long reflection seismic profiles crossing this region in the Dannemora mining area. The interpretations are constrained by seismic wave velocity measurements on a series of rock samples, cross-dip analysis, prestack time migration, and swath 3-D imaging, as well as by other available geophysical and geological observations. A series of major fault zones is imaged by the seismic data, as is a large mafic intrusion. However, the most prominent feature is a package of east-dipping reflectors found east of the Dannemora area that extend down to at least 3 km depth. This package is associated with a polyphase, ductile-brittle deformation zone with the latest ductile movement showing east-side-up or reverse kinematics. Its total vertical displacement is estimated to be in the order of 2.5 km. Also clearly imaged in the seismic data is a steeply dipping reflector near the Dannemora mine that extends down to a depth of at least 2.2 km. The geological nature of this reflector is not known, but it could represent either a fluid-bearing fault zone or a deep-seated iron deposit, making it an important target for further detailed geophysical and geological investigations. Copyright 2011 by the American Geophysical Union. 2011 Journal Article http://hdl.handle.net/20.500.11937/9090 10.1029/2011JB008643 Blackwell Publishing Ltd unknown
spellingShingle Malehmir, A.
Dahlin, P.
Lundberg, E.
Juhlin, Christopher
Sjöström, H.
Högdahl, K.
Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title_full Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title_fullStr Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title_full_unstemmed Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title_short Reflection seismic investigations in the Dannemora area, central Sweden: Insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
title_sort reflection seismic investigations in the dannemora area, central sweden: insights into the geometry of polyphase deformation zones and magnetite-skarn deposits
url http://hdl.handle.net/20.500.11937/9090