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Early phases of Caledonian deformation in the Dalradian of the Ballachulish district, Argyll
Author(s) -
Bowes D. R.,
Wright A. E.
Publication year - 1973
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350080211
Subject(s) - crenulation , lineation , dalradian , geology , cataclastic rock , fold (higher order function) , metamorphism , geochemistry , metamorphic rock , schist , nappe , cleavage (geology) , glaucophane , tectonics , seismology , fracture (geology) , shear zone , paleontology , subduction , mechanical engineering , engineering , eclogite
Abstract Two early phases of deformation preceded the development of the major NE‐SW‐trending folds, including the Appin Fold. The earliest recognized structures include small folds, lineations and inclusion trails in garnet porphyroblasts. The dominant schistosity and mineral lineation was developed during the second phase of deformation, associated with the formation of similar folds and tectonic banding, under garnet grade conditions over much of the area. The later‐formed major folds are associated with low grade retrogressive metamorphism and crenulation and fracture cleavage formation. These folds are concentric folds and have associated tectonic slides producing low grade cataclastic schists. On the basis of fold style and sequence and metamorphic grade there is a great similarity between the structures in the Dalradian rocks of the Ballappel Foundation and those of the Iltay Nappe.