Large-scale 3-D Gravity Analysis of the Inhomogeneities in the European-Mediterranean Upper Mantle

-Methods and the results of estimating the anomalies characterising the density inhomo geneities in the European-Mediterranean upper mantle are described. These anomalies were obtained by subtracting the gravity effect of a crustal density model derived from seismic velocities from the observed grav...

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Bibliographic Details
Published in:Pure and applied geophysics 1998-03, Vol.151 (2-4), p.549-561
Main Authors: Yegorova, T P, Starostenko, VI, Kozlenko, V G
Format: Article
Language:English
Subjects:
Anomalies
Basins
Density
Geophysics
Gravitation
Gravity
Gravity effects
Heterogeneity
High temperature
Lithosphere
Mantle
Mathematical models
Mineralogy
Plate tectonics
Seismic phenomena
Seismology
Upper mantle
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Summary:-Methods and the results of estimating the anomalies characterising the density inhomo geneities in the European-Mediterranean upper mantle are described. These anomalies were obtained by subtracting the gravity effect of a crustal density model derived from seismic velocities from the observed gravity field averaging over an area of 1 degree 1 degree . The 3-D density model of the study region comprises two regional layers of varying thickness with lateral variation of average density the sedimentary cover and the crystalline crust. The average densities for model layers were evaluated by using a velocity/density conversion function and taking into account sediment consolidation with depth. Clear correlation between residual gravity anomalies and both velocity heterogeneities and thermal regime data of the upper mantle has been revealed. An agreement of positive anomalies over the Alps, the Adriatic plate and the Calabrian Arc with high velocity domains in the upper mantle and reduced temperatures at the subcrustal layer are caused by lithospheric "roots" and thickened lithosphere below these structures. Gravity residual lows, revealed over the Western Mediterranean Basin and Pannonian Basin, are in correspondence with both low velocities and high temperatures in the upper mantle. These anomalies are the result of the presence of asthenosphere in shallow near-Moho depths below these basins.
ISSN:0033-4553
1420-9136
DOI:10.1007/s000240050129