| Title | 40Ar/39Ar geochronological data from the Sutton/Green Mountains anticlinorium, southern Quebec-northern Vermont Appalachians: episodic and diachronous tectonism from Middle Ordovician to Middle
Devonian |
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| Author | Castonguay, S ;
Doolan, B; Gale, M; Kim, J; Ruffet, G; Thompson, P; Tremblay, A; Villeneuve, M |
| Source | Geological Society of America, Northeastern Section - 40th Annual Meeting; Geological Society of America, Abstracts With Programs vol. 37, no. 1, 2005 p. 30 |
| Links | Online - En ligne
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| Year | 2005 |
| Alt Series | Earth Sciences Sector, Contribution Series 2004319 |
| Meeting | Geological Society of America, Northeastern Section - 40th Annual Meeting; Saratoga Springs, New York; US; March 14-16, 2005 |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | htm |
| Province | Quebec |
| Area | Sutton/Green Mountains; Appalachians; United States of America |
| Subjects | general geology; tectonics; metamorphic rocks; deformation; argon argon dating; argon argon dates; foliation; metamorphism; Devonian; Ordovician |
| Program | Targeted Geoscience Initiative (TGI-2), 2003-2005 |
| Released | 2005 01 01 |
| Abstract | In the southern Quebec-northern Vermont Appalachians, metamorphic rocks of the Laurentian margin crop out along a mega-structure, the Notre-Dame-Sutton-Green Mountains anticlinoria, which progressively
exposes deeper tectonometamorphic levels from North (southern Quebec) to South (northern Vermont). Regional deformation and metamorphism of these rocks are currently attributed to the combined effects of Taconian (Middle-Late Ordovician) and Acadian
(Middle Devonian) orogenies, and consist of three generations of superimposed folds and faults and at least one (Taconian) metamorphic paragenesis. Recently-acquired 40Ar/39Ar isotopic data from several sections across the mega-structure has revealed
age groups; (1) Middle Devonian, (2) Silurian-Early Devonian, (3) Middle Ordovician, and (4) Precambrian. The second 40Ar/39Ar age group is of special interest as it spans the apparent period of relative tectonic quiescence between the Taconian and
Acadian orogenies. In the Sutton Mountains anticlinorium transect, this group of ages (430-405 Ma), occurs throughout the anticlinorium structure and an overall west-to-east age decrease is observed. In the northern Green Mountain anticlinorium
transect, preliminary 40Ar/39Ar data of that age group appears to be slightly older (441-430 Ma). These latter ages were obtained from white micas in rock samples where the second regional foliation (S2) is penetrative and interpreted to be
associated with SE-verging structures. In southern Quebec, 40Ar/39Ar age data from similar fabrics are interpreted as deformation ages that characterize Silurian-Early Devonian, hinterland-directed thrusting and extensional faulting. Preliminary age
data of northern Vermont and along-strike structural correlations of regional fabrics between Vermont and Quebec suggest that their overall tectonic evolution has been similar. In summary, structural analyses and geochronological data from both
transects suggest episodic and diachronous tectonism characterized by contrasting structural vergences and metamorphic conditions. |
| GEOSCAN ID | 216742 |
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