Deep seismic data from the Bay of Fundy and Gulf of Maine: tectonic implications for the northern Appalachians

Détails

ID Serval
serval:BIB_88DC54D7BCEC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Deep seismic data from the Bay of Fundy and Gulf of Maine: tectonic implications for the northern Appalachians
Périodique
Canadian Journal of Earth Sciences
Auteur⸱e⸱s
Keen C., Kay W., Keppie D., Marillier F, Pepiper G., Waldron J.
ISSN-L
0008-4077
Statut éditorial
Publié
Date de publication
1991
Peer-reviewed
Oui
Volume
28
Pages
1096-1111
Langue
anglais
Résumé
Three deep-penetration seismic reflection profiles were collected
off southwest Nova Scotia to determine the crustal structure and
geometry beneath the Avalon and Meguma zones of the Appalachian Orogen
in Canada. Onshore geological features have been traced seawards
using new gravity and magnetic anomaly maps. The seismic data can
also be correlated with the previous United States Geological Survey
profile in the central Gulf of Maine.
Two seismically distinct lower crustal blocks are identified: the
Avalon and Sable lower crustal blocks, separated by a major north-dipping
reflection zone that cuts the entire crust. The recognition of the
Sable block adds a fourth block to the three already identified in
the Canadian Appalachians. The Sable block is overlain by the Meguma
Zone. The Avalon Zone overlies at least the northern part of the
Avalon lower crustal block. Although offshore extension of geological
features is not unequivocal, it appears that a north-dipping reflection
zone southwest of Nova Scotia marks the site of Devonian thrusting
of Avalon Zone over Meguma Zone. In the Bay of Fundy to the north,
two south-dipping reflection zones are interpreted as major thrusts,
possibly placing Avalon lower crust over a unit with different tectonic
affinities. The Fundy Fault is a Carboniferous thrust within the
Avalon block along the coast of New Brunswick; this was reactivated
during Mesozoic extension as a transtensional fault. Extensional
displacement farther southwest was probably accommodated along east-west-trending
faults and small rift basins associated with them.
Mots-clé
NOVA-SCOTIA, CANADIAN APPALACHIANS, TERRANE, MEGUMA, PROFILE, ISLAND, MARGIN, ZONE
Création de la notice
25/11/2013 19:03
Dernière modification de la notice
20/08/2019 14:47
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