Foliations Flashcards
1
Q
Origin of gneissic layering
A
- Inheritance of compositional contrast from the protolith
- ## Transposition
- Differentiation
-generation of new layering during deformation/metamorphism
-higher pressure in zones of shearing
-solubility of certain materials increases
-shearing happens oblique or perpendicular to original orientation - Lit-par-lit (layer-by-layer) intrusion of sills
-layers intruded
2
Q
transposition
A
What is it?
Rotation of a pre-existing foliation (e.g., bedding) by folding into an orientation approximately parallel to the axial plane of the folds
development of a new orientation of bedding in such a way that bedding, as seen in small outcrops, no longer provides information concerning stratigraphy or gross distribution of
stratigraphic horizons.