Boundin is a french word for
Sausage
a process of stretching, necking and eventually segmentation of competent layer
boudinage
strongest layer or most competent layers formed inn boudin
rectangular boudins
less competent layers developed
pinch-and-swell structures
What does the shape of the boudin reflect during deformation
Ductility contrast between the layer and the matrix.
large contrast produce boudin with
sharp edges
Small contrast boudin creates
rounded boudin
The competent layer behaves in a brittle manner, forming discrete extension fractures.
Large viscosity difference
The layers deform ductilely, thinning locally (necking) before fracturing.
Small viscosity difference
What controls the range of boudin profiles during deformation?
rheological contrast between the layer
boudin that are separated by the material that originally lay on either side of segmented layer or by a mineral aggregate
Boudin with a blocky geometry
Boudin separated by shear fracture\es are sometimes pulled apart without much rotation or shear
Symmetric boudinage
Boudins are offset by shear structures, significant rotation of the boudin occurs
Asymmetric boudinage
These are boudins that formed at higher grades. where the competent layers have generally not broken enough
boudins with a wavy geometry
occurs in homogeneous, strongly foliated rocks with no lithological contrast between segmented rock and the host rocks
Foliation boudinage
The type of foliation boudinage that is seperated wby tensile fractures.
Symmetrics
Type of boudinage that is common in medium to high grade metamorphic rocks. The shape of it is frequently used as a sense of shear indicator
Asymmetric
Type of boudinage that have layer-parallel extension that may take in two directions. It also describe the 3D, blocky fragmentation of layer
Chocolate-Tablet Boundinage
