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TitleGaspé belt subsurface geometry in the northern Québec Appalachians as revealed by an integrated geophysical and geological study: 1- Potential field mapping
AuthorPinet, N; Lavoie, D; Keating, P; Brouillette, P
SourceTectonophysics vol. 460, 2008 p. 34-54,
Alt SeriesEarth Sciences Sector, Contribution Series 20080280
Mediapaper; on-line; digital
RelatedThis publication is related to Pinet, N; (2013). Gaspé Belt subsurface geometry in the northern Québec Appalachians as revealed by an integrated geophysical and geological study: 2- Seismic interpretation and potential field modelling results, Tectonophysics vol. 588
File formatpdf
NTS22A; 22B; 22G/01; 22G/02; 22H/01; 22H/02; 22H/03; 22H/04
AreaGaspé; Appalachians
Lat/Long WENS-68.0000 -64.0000 49.5000 47.5000
Subjectsgeophysics; structural geology; geometric analyses; basin geometry; geophysical surveys; gravity surveys; aeromagnetic interpretation; aeromagnetic surveys; bedrock geology; structural features; faults; tectonostratigraphic zones; gravity interpretations; geophysical interpretations; Gaspé Belt; Carboniferous; Silurian; Devonian; Paleozoic
Illustrationslocation maps; graphs; block diagrams; images
ProgramSecure Canadian Energy Supply
AbstractTogether, recent gravity and high-resolution aeromagnetic datasets are used to qualitatively investigate the upper- and middle-crustal geometry of the Middle Paleozoic Gaspé belt in the northern Appalachians. Long wavelength potential-field anomalies define two sub-basins that are divided by northeast trending gravity highs. For each sub-basins, gravity lows correlate with the youngest rock units.
Maps that highlight anomalies associated with near surface features, at the expense of those related to deeper sources, provide an important supplement to the spatially discrete observations derived from bedrock mapping. Analysis of such maps indicates that the sub-basins are characterized by different structural patterns and that faults trending obliquely compared to the main structural grain have been previously underestimated.
The geometry of the Gaspé belt as revealed by this integrated geophysical and geological study bears similarities with orogens exhibiting lateral extrusion. This geometry is interpreted as the result of a heterogeneous strain regime in front of an indenter corresponding to the Early Paleozoic Gander crustal block. The indentation tectonic model is supported by: 1) the various strike and kinematic of faults that suggest a strongly heterogeneous strain regime; 2) the greater geological complexity and the occurrence of faults with a significant thrust component in front of the indenter; 3) the predominance of right-lateral strike-slip faults in the eastern Gaspé Peninsula that result in lateral material transport away from the indenter; 4) the location of abundant Devonian magmatic dykes, sills and stocks in a fault-bounded zone that experienced local extension; 5) the occurrence of blocks rotation.