info:eu-repo/semantics/article
MOBILE BELT-CRATON TECTONIC RELATIONSHIPS IN PRECAMBRIAN GONDWANALAND AND: MEGA-ANALOG OF STRUCTURAL FEATURES FOUND IN SHEAR AND MYLONITE ZONES?
MOBILE BELT-CRATON TECTONIC RELATIONSHIPS IN PRECAMBRIAN GONDWANALAND AND: MEGA-ANALOG OF STRUCTURAL FEATURES FOUND IN SHEAR AND MYLONITE ZONES?
Autor
KATZ, MICHAEL B.
Institución
Resumen
Archean cratons-Proterozoie mobile belts mega-structural relationships in Precambrian Gondwanaland can be compared to meso-microstructures found in ductile mylonite and shear zones. The large Archean cratons are comparable to the much smaller scale, porphyroclasts in shear and mylonites. The late Archean-Proterozoie mobile belts resemble large scale equivalents of the fine-grained, ductile matrix of shear and mylonite zones. The relationships are excellent examples of high strain, deformation of vastly different magnitudes (in the order of 106). The processes of deformation within a shear or mylonite zone have been described in some detail and may serve as a deformation scale model for craton-mobile belt relationships. The craton-mobile belts recognized in Precambrian Gondwanaland and Austrália are analysed using whole rock strain methods that are usually applied to meso-microstructures. This assumes simple, ideal eonditions of deformation, of originally circular era tons. The particle (or craton)-centre to centre technique applied on the mega-scale suggests that the greatest relative extension in Precambrian Gondwanaland is between the South American and Australian era tons. Within Precambrian Austrália a similar exercise results in greatest extension between Pilbara and Gawler cratons. These results lead to the development of a concept that the Archean cratons were once originally part of a larger craton unit, or were close neighbours, and have been subsequently deformed and disrupted in their transform mobile belt matrix, in late Archean-Proterozoic times. Archean cratons-Proterozoie mobile belts mega-structural relationships in Precambrian Gondwanaland can be compared to meso-microstructures found in ductile mylonite and shear zones. The large Archean cratons are comparable to the much smaller scale, porphyroclasts in shear and mylonites. The late Archean-Proterozoie mobile belts resemble large scale equivalents of the fine-grained, ductile matrix of shear and mylonite zones. The relationships are excellent examples of high strain, deformation of vastly different magnitudes (in the order of 106). The processes of deformation within a shear or mylonite zone have been described in some detail and may serve as a deformation scale model for craton-mobile belt relationships. The craton-mobile belts recognized in Precambrian Gondwanaland and Austrália are analysed using whole rock strain methods that are usually applied to meso-microstructures. This assumes simple, ideal eonditions of deformation, of originally circular era tons. The particle (or craton)-centre to centre technique applied on the mega-scale suggests that the greatest relative extension in Precambrian Gondwanaland is between the South American and Australian era tons. Within Precambrian Austrália a similar exercise results in greatest extension between Pilbara and Gawler cratons. These results lead to the development of a concept that the Archean cratons were once originally part of a larger craton unit, or were close neighbours, and have been subsequently deformed and disrupted in their transform mobile belt matrix, in late Archean-Proterozoic times.