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| Titel |
EURho: Density structure of the European crust and lithospheric mantle |
| VerfasserIn |
Kasper Lundvig, Irina Artemieva, Hans Thybo |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147925
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| Publikation (Nr.) |
 EGU/EGU2017-12144.pdf |
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| Zusammenfassung |
| We present a new density model of the (1) European crust and (2) lithospheric mantle by
integrating seismic, thermal and gravimetric data. (1) Crustal density: We obtain
crustal segment thicknesses (i.e. sediments, upper crust, middle crust, lower crust and
lowermost crust) and mean p-wave segment velocity (vp) from the recent seismic
crustal model EUNAseis (Artemieva and Thybo, 2013). By converting each mean
crustal segment vp into mean crustal segment rock density using Brocher’s empirical
polynomial relationship (Brocher, 2005), we calculate mean crustal density for the entire
crustal column as a weighted mean. (2) Lithospheric mantle density: Due to strong
seismic anisotropy in the European lithospheric mantle, we limit the vp to rock
density conversion to the crust. Instead, we estimate lithospheric mantle densities
from residual mantle gravity. We use crustal segment densities to calculate the total
crustal gravimetric contribution. We find a strong linear relationship between crustal
thickness and crustal gravimetric contribution, and we exploit this relationship as our
reference model. We remove the anomalous crustal gravimetric contribution by
subtracting it from the Free-Air Anomaly in WGM2012 (Balmino et al., 2012). By
implementing the thermal model TC1 (Artemieva, 2006) and by defining the base of the
lithosphere as the depth where the local geotherm reaches a temperature of 1300 oC we
effectively constrain the thickness of the thermal lithosphere. We remove the effect of
undulating Moho and LAB (Lithosphere Asthenosphere Boundary) depth variations, and
the effect of thermal expansion. From the resulting residual mantle gravity, we
estimate lithospheric mantle density on a 1 x 1 degree’s grid. Our results show that the
thick crust in the East European Craton (East European Platform and shield and the
Baltic shield) is significantly denser (2.83 ± 0.05 Mg m−3) than the thin crust in
Western Europe (2.77 ± 0.04 Mg m−3). Contrastingly, the thick lithospheric mantle in
Eastern Europe is slightly less dense (3.34 ± 0.03 Mg m−3) than the thin lithospheric
mantle in Western Europe (3.36 ± 0.03 Mg m−3). The weighted mean density
for the entire lithosphere of Eastern and Western Europe is remarkably similar
with a mean density of 3.21 ± 0.03 Mg m−3 and 3.2 ± 0.04 Mg m−3 respectively.
Additionally, we find very high densities (3.4 – 3.46 Mg m−3) in the lithospheric
mantle beneath the Peri-Caspian basin and the North German basin, suggesting
that eclogitization processes could play a role in the formation of these basins. |
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