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| Titel |
Slow upper mantle beneath Southern Norway from surface waves |
| VerfasserIn |
C. Weidle, V. Maupin |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026563
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| Zusammenfassung |
| A recent regional surface wave tomography for Northern Europe revealed unprecedented
images of the upper mantle beneath the (Tertiary) North Atlantic and the bordering
Fennoscandian craton of Archean-Proterozoic age. With respect to the circum-Atlantic
regions of uplift, no common mantle pattern supporting the uplift of these regions is
observed.
The western boundary of the thick cratonic lithosphere follows the trend of the continental
margin offshore northern Norway (i.e. the northern Scandes are underlain by thick
lithosphere) whereas further south the boundary of the craton is located further east beneath
southwestern Sweden. SV shear wave velocities beneath southern Norway are 10% slower
than ak135 (at 70-115 km depth) and these low-velocities are clearly connected to the North
Atlantic low-velocity regime through a ~ 400 km wide "channel". The low-velocity anomaly
beneath Southern Norway coincides in geometry roughly with the dome-like high topography
of the southern Scandes and may thus have a non-negligible contribution to the isostatic
balance of the region.
The amplitude and depth-distribution of this anomaly are due to be further constrained by
new data that were acquired during the MAGNUS experiment in 2006-2008. The temporary
seismic network, consisting of 40 broadband seismometers covers to a large extent the
location of the anomaly as imaged by the regional tomography. This enables us to get unique
control on the tomographic model at improved lateral and vertical resolution. Preliminary
analysis of surface wave phase velocities yields an average 1-D shear wave velocity profile
for southern Norway as a first step to constrain the presence and depth extent of this
low-velocity anomaly. |
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