Laterally persistent seismic characteristics of the lower crust: examples from the Northern Appalachians

Détails

ID Serval
serval:BIB_5CE36A5A72A8
Type
Partie de livre
Collection
Publications
Titre
Laterally persistent seismic characteristics of the lower crust: examples from the Northern Appalachians
Titre du livre
Properties and Processes of the Earth's Lower Crust
Auteur(s)
Marillier F., Keen C., Stockmal G.
Editeur
American Geophysical Union
ISBN
9780875904566
Statut éditorial
Publié
Date de publication
1989
Volume
6
Série
Geophysical Monograph
Pages
45-52
Langue
anglais
Notes
Marillier1989
Résumé
Over 1600 km of deep seismic data were recently acquired to probe
the crust and the upper mantle of the Appalachians in Canada. Although
it is usually difficult to relate the surface expression of tectonic
provinces to characteristic seismic signatures in the crust, our
data show consistent seismic patterns in the lower crust, over distances
of several hundreds of kilometres. These patterns enable us to identify
three lower crustal blocks which underlie the orogen. In some places,
boundaries between crustal blocks are identified by consistent differences
in the seismic character of the Moho reflections. We suggest that
one of these block boundaries (between the Central and Avalon crustal
blocks) corresponds to a fault at the surface which has been identified
as the Gander-Avalon terrane boundary.
High reflectivity of the lower crust and/or bright elongated Moho
reflections are observed along some profiles where velocities higher
than 7.0 km/s have been measured by earlier refraction studies. Although
similar observations have been associated with extensional terranes
by many authors, our data indicate that they can also be found in
convergent environments.
Création de la notice
25/11/2013 20:03
Dernière modification de la notice
20/08/2019 15:15
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