Upper mantle beneath the Eger Rift (Central Europe): Plume or asthenosphere upwelling?

• Published in: Geophysical journal international Vol. 169; no. 2; pp. 675 - 682
• Main Authors: Plomerová, Jaroslava, Achauer, Ulrich, Babuška, Vladislav, Vecsey, Luděk
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2007
• Subjects: Eger Rift; seismic anisotropy; tomography
• ISSN: 0956-540X; 1365-246X
• DOI: 10.1111/j.1365-246X.2007.03361.x

We present the first results of a high-resolution teleseismic traveltime tomography and seismic anisotropy study of the lithosphere–asthenosphere system beneath the western Bohemian Massif. The initial high-resolution tomography down to a depth of 250 km did not image any columnar low-velocity anomaly which could be interpreted as a mantle plume anticipated beneath the Eger Rift, similar to recent findings of small plumes beneath the French Massif Central and the Eifel in Germany. Alternatively, we interpret the broad low-velocity anomaly beneath the Eger Rift by an upwelling of the lithosphere–asthenosphere transition. We also map lateral variations of seismic anisotropy of the mantle lithosphere from spatial variations of P-wave delay times and the shear wave splitting. Three major domains characterised by different orientations of seismic anisotropy correspond to the major tectonic units—Saxothuringian, Moldanubian and the Teplá-Barrandian—and their fabrics fit to those found in our previous studies of mantle anisotropy on large European scales.