Flanking structures an deflections of planar or linear fabric elements in a
rock alongside a cross-cutting object such as a vein, fracture or burrow.
Flanking structures are divided into flanking-folds and flanking shear-band
s. Both structures can develop by a range of mechanisms including intrusion
or in situ formation of veins that bisects existing fold trains or shear-b
ands along the axis of the structure; flow partitioning alongside an active
fault in a ductilely deforming rock; passive rotation of a vein with attac
hed nl row rim of wall rock formed by alteration of the wall rock during in
trusion of the vein; development of a shear zone in or along a pre-existing
vein; and passive amplification of small deflections alongside a vein or b
urrow. Flanking structures can he used to establish a sequence of deformati
on and intrusion or partial melting, and some types of flanking structures
can he used as shear sense indicators or to determine finite strain. (C) 20
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