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Constriction due to subduction: evidence for slab pull in the Mariánské Lázně complex (central European Variscides)
Author(s) -
Zulauf Gernold
Publication year - 1997
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1997.tb00019.x
Subject(s) - geology , subduction , eclogite , slab , mantle (geology) , eclogitization , seismology , geochemistry , petrology , geophysics , tectonics , oceanic crust
Pervasive L and L ≪ S tectonites of the Mariánské Lázně eclogites include pencil fabrics, constrictional folds and mullions, that result from the first deformation increment observed. Petrological and microstructural data suggest that these structures formed by constrictional flow at deep subduction levels after, or even during, the eclogite facies stage and before the subsequent high‐pressure granulite facies overprint. Constriction at mantle depths is explained by taking into account the geometry and seismic properties of recent subduction zones. Here, constrictional strain and associated L ≫ S tectonites should be expected below the rheologycontrolled slab bend (at about 40 km depth), where dip‐parallel extension and a reduced viscosity of the downgoing slab are compatible with a coaxial flow regime.