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S.B. Nielsen

Upper mantle and crustal structure of the East Greenland Caledonides: New geophysical evidence and geodynamic implications

Research output: Contribution to conferenceConference abstract for conferenceResearch

The East Greenland and Scandinavian Caledonides once formed a major coherent
mountain range, as a consequence of the collision of the continents of Laurentia and Baltica. The crustal and upper mantle structure was furthermore influenced by several geodynamic processes leading to the formation of the North Atlantic passive margins, including the gravitational collapse, extension, rifting and a possible influence by volcanism related to the Iceland hot spot. The landscape and topography were finally shaped by extensive erosion, finding its peak in the quaternary glaciations.
Seismological data were acquired in the East Greenland Caledonides by the Ella-Ø-array for a period of two years (2009-2011). The array containing 11 broadband seismometers was situated at approximately 73 °N covering a distance of 270 km from the Greenland Ice Sheet to the Atlantic coast, north of the Iceland Ridge. A Receiver Function study based on an average of 36 events per station reveals a clear eastward dipping high-velocity structure underneath the study area. The geophysical character, supported by synthetic modelling, is consistent with a 10 km thick subducted slab of eclogitized oceanic crust. This might be the key for unravelling of a complex geodynamic setting and development leading to the formation of the Caledonides. The distinct preservation of structures in the upper mantle to depths of 100 km or more, limits the impact of subsequent collision and extension related deformation.
In support of this interpretation, we present selected results from on-going detailed studies of the crustal and upper mantle, including a Receiver Function inversion, seismic P-wave travel time tomography and gravity
modelling.
Original languageEnglish
Publication year9 Dec 2013
Number of pages1
Publication statusPublished - 9 Dec 2013
Event2013 AGU Fall Meeting - San Francisco, United States
Duration: 9 Dec 201313 Dec 2013

Conference

Conference2013 AGU Fall Meeting
CountryUnited States
CitySan Francisco
Period09/12/201313/12/2013

    Research areas

  • East Greenland , Caledonides, Receiver Functions, Numerical modelling, Seismology, North Atlantic

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