Non-cylindrical folds, linear structures in the X direction and mylonite developed during translation of the Caledonian Kalak Nappe Complex of Finnmark

• Published in: Geological Magazine
• Main Authors: Rhodes, S., Gayer, R. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1977
• Subjects: Geology; The ''Y''; Kalak; Finnmark
• Online Access: http://dx.doi.org/10.1017/s0016756800036645; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800036645

Summary Structural evidence from the Kalak Nappe Complex suggests the operation of layer parallel shearing stresses during the translation of the nappes. A simple shear model invoking irregular areas of high cohesion within individual layer boundaries is used to explain the development of both intra-folial, cylindrical and non-cylindrical folds and a regular zone of syn-folding blasto-mylonite at the base of the nappe(s). Fold hinges that are initially developed parallel to the Y axis of the strain ellipsoid during layer parallel shearing may be rotated towards the X direction as a result of large strains concentrated at points of high cohesion within the layering boundaries.