Example of Knauern, tension gashes with kyanite and/or andalusite
The first two observed phases D1 and D2 form isoclinal*
folds and are related to overthrusting
movement* towards the N-NW as part of the emplacement of the Simano
nappe*. D2 is responsible
for the main schistosity*
and N-S main lineation*
in all lithologies*.
causes the opening of tension
gashes* and the crystallization of the tension gashes (also known
and is related to top-North shearing. This phase is contemporary
of the Tertiary*
of metamorphism* (peak of temperature, see next
page) in amphibolites facies*,
which is marked by the assemblage* kyanite,
garnet and staurolite in metapelites* and
hornblende (tschermakite), plagioclase and garnet or biotite in amphibolites*.
The D4 phase of West vergent* transverse
folding* give rise to the dominant fold structures in the studied
area, including the great Lareccio anticline*.
This fourth phase is at the origin of a new coarse schistosity S4,
which develops in the hinges*
of the great fold structures.
This D4 phase occurs always in amphibolite facies and shows a
deflection of the major lower
Pennine* unities towards W during the tectonic
The last D5 phase causes a coarse vertical crenulation*
due to vertical shortening during last stage of
the ductile deformation history.