| Titre | Dating polyphase deformation across low-grade metamorphic belts: an example based on 40Ar/39Ar muscovite age constraints from the southern Quebec Appalachians, Canada |
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| Auteur | Castonguay, S ;
Ruffet, G; Tremblay, A |
| Source | Geological Society of America Bulletin vol. 119, no. 7/8, 2007 p. 978-992, https://doi.org/10.1130/B26046.1 |
| Image |  |
| Année | 2007 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20060013 |
| Éditeur | Geological Society of America |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1130/B26046.1 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Québec |
| SNRC | 21E/04; 21E/05; 21E/11; 21E/12; 21E/13; 21E/14; 21E/15; 21L; 31H; 31I/01; 31I/02; 31I/03; 31I/07; 31I/08; 31I/09; 31I/10; 31I/16 |
| Région | Appalachians; Montréal; Drummondville |
| Lat/Long OENS | -74.0000 -70.0000 47.0000 45.0000 |
| Sujets | datations argon-argon; datation argon-argon; datation radiométrique; datations radiométriques; muscovite; métamorphisme; métamorphisme polyphasé; métamorphisme, faible teneur; déformation; faciès
métamorphiques; faciès à schiste vert; recristallisation; cadre tectonique; Zone de Dunnage ; Zone d'Humber ; Faille de Brome ; Zone de faille de Stukely-Sud ; Anticlinorium de Sutton Mountains ; géochronologie; pétrologie ignée et métamorphique;
tectonique; géologie structurale; Paléozoïque; Dévonien; Silurien; Ordovicien; Protérozoïque |
| Illustrations | croquis cartographiques; photographies; photomicrographies; graphiques |
| Programme | Consolidation du savoir géoscientifique du
Canada |
| Programme | Projet de l'avant-pays appalachien et de la Plate-forme du Saint-Laurent du CARTNAT |
| Diffusé | 2007 07 16 |
| Résumé | (disponible en anglais seulement)
Geochronologic 40Ar/39Ar data of fabric-forming metamorphic minerals, in conjunction with structural and metamorphic studies, are being increasingly used to
constrain the deformation and tectonometamorphic evolution of polyphase low-grade orogens. Careful data interpretation is needed to extract meaningful age constraints from neo- and recrystallized minerals affected by isotopic disturbances. In the
southern Quebec Appalachians, the Sutton Mountains anticlinorium exposes the metamorphic core of the early Paleozoic continental margin of Laurentia. Orogenesis in this part of the Appalachians was the result of tectonic events that have been
classically attributed to the combined effects of the Middle to Late Ordovician Taconian and the Middle Devonian Acadian orogenies; however, evidence of separate and distinct Silurian-Early Devonian tectonism has also been recently documented. Laser
step-heating 40Ar/39Ar data on single-grains of muscovite from polydeformed greenschist facies samples of the Sutton Mountains anticlinorium indicate that these tectonometamorphic events are heterogeneously preserved as a prograde Taconian event at
ca. 456 Ma and an Acadian overprint at ca. 390 Ma. The integration of 40Ar/39Ar age spectra analyses with structural relationships provides precise age constraints on the duration, propagation, and evolution of Silurian-Early Devonian
hinterlanddirected deformation as it migrated across the anticlinorium, including back thrusting from ca. 433 Ma to ca. 420 Ma and extensional faulting from ca. 417 Ma to ca. 405 Ma. Along the Laurentian margin of the northern Appalachians, such
Silurian-Early Devonian tectonism is currently attributed either to the collapse of the Taconian orogen triggered by the delamination of the subducted slab or to the outboard accretion of peri-Gondwanan terranes during the Salinic orogeny. |
| GEOSCAN ID | 222092 |
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