0000000000871102
AUTHOR
David Iacopini
Fabric attractors in general triclinic flow systems and their application to high strain shear zones: A dynamical system approach
High strain zones may deform by flow with a triclinic symmetry. This paper describes triclinic flow in a reference frame where Instantaneous Stretching Axes (ISA) are fixed. The operation of triclinic flow is described in two ways: first in terms of flow and the nature of flow eigenvectors and in the second part of the paper in terms of finite strain. In monoclinic flow, at least one of the eigenvectors of the flow coincides with one of the ISA and one or two of the eigenvectors act as attractors of foliation or lineation elements. In triclinic flow some flow eigenvectors are undefined since the two largest eigenvalues (controlling the flow) are imaginary. Imaginary eigenvalues are particul…
Strain analysis and vorticity of flow in the Northern Sardinian Variscan Belt: Recognition of a partitioned oblique deformation event
Abstract A field example of strain partitioning has been analysed along the Nurra–Asinara transect of the NW Sardinian Variscan chain (Italy). The section in the Nurra–Asinara area is in a continuous sequence of tectono-metamorphic complexes made of low- to high-grade metamorphic rocks affected by a polyphase tectonic history. The principal fabric of the area is controlled by a D2 progressive deformation phase in which the strain is partitioned into folds and shear zone domains. The D2 stretching lineation and shear sense show a clear change from south to north. The principal meso- and micro-structures, vorticity gauges and a quantitative kinematic analysis of local strain suggest that the …