Fissuring in sandstones

"The structure known as 'fissuring' is widely developed in sandstones interbedded with slates in the closely folded marine Ordovician rocks of the gold fields of central Victoria, Australia. Fissures are here described, and interpreted as flow layers analogous to those that form in plastically deformed metals. In fissured sandstones, two complementary sets of microscopical shearing planes are present, with the bisectrix of the acute dihedral angle between them normal to the bedding. Fissures form in both of these shearing directions, and also in the plane of flattening of the rock."

This record provided courtesy of AGI/GeoRef.