Non-axial planar cleavage and Caledonian sinistral transpression in eastern Ireland

Autor: F. C. Murphy
Rok vydání: 2007
Předmět:
Zdroj: Geological Journal. 20:257-279
ISSN: 1099-1034
0072-1050
DOI: 10.1002/gj.3350200307
Popis: Transected F1 fold structures in eastern Ireland are associated with subhorizontal stretching in the S1, cleavage whereas axial planar cleavage contains a vertical elongation direction. This suggests that the non-axial planar cleavage was influenced by a distributed strike-slip ductile shear. A major NE-SW trending F1 syncline is described in which the minor F1 folds show systematic variations in cleavage transection parameters. On the steep limb of the major syncline the cleavage transects the minor F1 folds in a consistently clockwise sense, whereas on the normal limb anticlockwise transected folds are seen. Axial planar cleavage occurs at the core of the major syncline. Fold profile analysis indicates that the buckling of the layers began before the initiation of the cleavage. Open, parallel folds at the major synclinal hinge zone are progressively ‘flattened’ on the steep limb towards a major D1 sinistral transcurrent fault. The angular transection, A, attains a maximum of 15° clockwise which diminishes to
Databáze: OpenAIRE
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