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TitleStructural reconnaissance of a deep crustal orogen using RADARSAT and Landsat satellite imagery and airborne geophysics
AuthorRivard, B; Corriveau, LORCID logo; Harris, L B
SourceCanadian Journal of Remote Sensing 25, 3, 1999 p. 258-267,
Alt SeriesGeological Survey of Canada, Contribution Series 1998271
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
NTS31G/09; 31G/10; 31G/11; 31G/12; 31G/13; 31G/14; 31G/15; 31G/16; 31J
AreaMont Laurier
Lat/Long WENS -76.0000 -74.0000 47.0000 45.5000
Subjectsstructural geology; geophysics; crustal studies; crustal evolution; crustal structure; orogenesis; satellite imagery; magnetic surveys, airborne; remote sensing; structural features; folds; faults; Central Metasedimentary Belt
Illustrationssketch maps; satellite images
Released2014 07 31
Understanding crustal evolution through studies of highly eroded orogens is a current scientific challenge worldwide. The marble and quartzite sequences and gneiss complexes of the Mont-Laurier area, in the Central Metasedimentary Belt of Quebec, form a collage of rheologically contrasting lithotectonic domains affected by successive orogenic and magmatic events. Landsat and RADARSAT satellite imagery, with their synoptic view and geomorphic detail, are well suited for the study of structurally complex terrains, especially when image analysis is integrated with regional field and geophysical data. For the Mont-Laurier area, the interpretations of such imagery led to the delineation of intrusive bodies, zones of ductile deformation, and fold interference patterns allowing refinements of existing 1: 50 000 maps and providing key information for reconnaissance mapping. The gneiss complexes record early Grenvillian convergence (pre-1.19 Ga) and display a highly contorted distribution of lithologies due to multiple fold interference patterns. On radar and Landsat imagery the complexes are relatively featureless structurally, due to the complex foliation trajectories and the small wavelength of folds. Greater success was obtained for similar structures, in gneisses of the quartzite domain, due to the larger amplitude of folds. Landsat TM band 4 imagery outlines the competency contrast of quartzite versus marble and can be used to map the domain of marble. At 1.165 Ga emplacement of the Chevreuil intrusive suite, concentrated along N-S corridors, marked the onset of renewed orogenic activity. Many of the intrusions from this suite have a unique topographic signature which can be delineated on the Landsat and RADARSAT imagery. Following the magmatic activity, late compressive deformation in the ductile regime was focused along the N-S corridors. The style of this deformation is characterized by a regional N-S foliation and coaxial anastamozing shear zones (NE-SW dextral; NW-SE sinistral) which were delineated in the radar imagery and confirmed using field kinematic indicators. The RADARSAT imagery provides a view of the extent of this deformation event and corroborates field and petrological studies indicating that by 1.165 Ga, the gneiss complexes were mechanically strong trustai domains and were only locally overprinted by late-stage ductile deformation.

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