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Fold and cleavage development within cambrian metasediments of the vale of ffestiniog, North Wales
Author(s) -
Hawkins T. R. W.,
Jones F. G.
Publication year - 1981
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.3350160107
Subject(s) - geology , cleavage (geology) , tectonics , fold (higher order function) , transverse plane , crenulation , paleontology , geochemistry , biology , anatomy , mechanical engineering , fracture (geology) , shear zone , engineering
New road cuttings have exposed a large part of the Merioneth Series. The rocks are low‐grade thinly layered metasediments which have undergone extensive buckling resulting in tectonic ripples, mullions, and crenulations. It is suggested that the periclinal form of these structures may be the result of buckling layered sequences with longitudinal and transverse zones of constraint (heterogeneities). The process is analogous to ‘quilting’ of thin metal sheets and the heterogeneities are perhaps due to layer thickness variation. There are two foliations; which may form a progressive sequence of cleavage development during the evolution of the fold style.