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| Titel |
Mantle lithosphere transition from the East European Craton to the Variscan Bohemian Massif imaged by shear-wave splitting |
| VerfasserIn |
L. Vecsey, J. Plomerova, V. Babuska |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 2 ; Nr. 5, no. 2 (2014-08-06), S.779-792 |
| Datensatznummer |
250115325
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| Publikation (Nr.) |
 copernicus.org/se-5-779-2014.pdf |
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| Zusammenfassung |
| We analyse splitting of teleseismic shear waves recorded during the PASSEQ
passive experiment (2006–2008) focused on the upper mantle structure across
and around the Trans-European Suture Zone (TESZ). Altogether 1009 pairs of
the delay times of the slow split shear waves and orientations of the
polarized fast shear waves exhibit lateral variations across the array, as
well as back-azimuth dependences of measurements at individual stations.
Variable components of the splitting parameters can be associated with
fabrics of the mantle lithosphere of tectonic units. In comparison with a
distinct regionalization of the splitting parameters in the Phanerozoic part
of Europe that particularly in the Bohemian Massif (BM) correlate with the
large-scale tectonics, variations of anisotropic parameters around the TESZ
and in the East European Craton (EEC) are smooth and of a transitional
character. No general and abrupt change in the splitting parameters
(anisotropic structure) can be related to the Teisseyre–Tornquist Zone
(TTZ), marking the edge of the Precambrian province on the surface. Instead,
regional variations of anisotropic structure were found along the TESZ/TTZ.
The coherence of anisotropic signals evaluated beneath the northern part of
the Brunovistulian in the eastern rim of the BM and the pattern continuation
to the NE towards the TTZ, support the idea of a common origin of the
lithosphere micro-plates, most probably related to Baltica. Smooth changes in
polarizations of the core-mantle boundary refracted shear waves (SKS),
polarizations, or even a large number of null splits northward of the BM and
further across the TESZ towards the EEC indicate less coherent fabrics and a
transitional character of structural changes in the mantle beneath the
surface trace of the TESZ/TTZ. The narrow and near-vertical TTZ in the crust
does not seem to have a steep continuation in the mantle lithosphere. The
mantle part of the TESZ, whose crust was formed by an assemblage of suspect
terranes adjoining the EEC edge from the southwest, appears in our
measurements of anisotropy as a relatively broad transitional zone in between
the two lithospheric segments of different ages. We suggest a southwestward
continuation of the Precambrian mantle lithosphere beneath the TESZ and the
adjacent Phanerozoic part of Europe, probably as far as towards the Bohemian
Massif. |
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