What is a boudin in geology?
Boudinage is a geological term for structures formed by extension, where a rigid tabular body such as hornfels, is stretched and deformed amidst less competent surroundings. The competent bed begins to break up, forming sausage-shaped boudins. They can also form rectangular structures.
What does chocolate tablet Boudinage tell us about the strain field?
To sum it up, boudinage is a very important structure when studying rocks in the field, which gives us important insights about deformation, rock strength, pressure and temperature conditions and the sense of shear.
What is a shear zone in geology?
A shear zone is a zone in which strain is clearly higher than in the wall rock, and whose margins are defined by a change in strain, typically seen by rotation of preexisting markers or formation of a new fabric. From: Earth-Science Reviews, 2017.
What are boudin links?
Boudin is a cooked sausage, in that everything is cooked before it’s ground up and stuffed into a casing. They’re sold in long links that are often tied into a ring and either poached and served or smoked to be eaten on the go.
What is Mullion geology?
A mullion is a structural element which divides adjacent window units. Mullion may also refer to: Mullion (geology), a geological term for structures formed by extension.
What is meant by the expression non coaxial deformation history?
What is meant by the expression non-coaxial deformation his- tory? It means that some or all of the three principal strain axes. rotate during deformation.
How shear zone is formed?
A shear zone is a very important structural discontinuity surface in the Earth’s crust and upper mantle. It forms as a response to inhomogeneous deformation partitioning strain into planar or curviplanar high-strain zones. Intervening (crustal) blocks stay relatively unaffected by the deformation.
What is the difference between shear zone and fault zone?
A shear zone is a zone in which shearing has occurred so that the rock mass is crushed and brecciated. A shear zone is the outcome of a fault where the displacement is not confined to a single fracture, but is distributed through a fault zone.
How would you describe boudin?
Boudin meaning
- A highly seasoned link sausage of pork, pork liver, and rice that is a typical element of Louisiana Creole cuisine.
- In France,
- A blood sausage similar to boudin noir popular in the cooking of the Cajuns.
What exactly is in boudin?
Boudin (pronounced “BOO-dan,” at least in Cajun country) is a cooked sausage made from pork meat and rice, plus various vegetables and seasonings, all stuffed in a natural pork casing. Traditional boudin features pork liver and/or pork heart along with scraps of pork meat from just about any part of the hog.
Where does the term Boudin come from in geology?
Boudins – the term comes from the French word for ‘sausage’ – are fragments of original layers that have been stretched and segmented. They develop in layers that are stronger and more resistant to deformation (i.e. more competent) than the surrounding rocks.
What is the meaning of the term boudinage?
Boudinage is a geological term for structures formed by extension, where a rigid tabular body such as hornfels, is stretched and deformed amidst less competent surroundings. The competent bed begins to break up, forming sausage-shaped boudins. Boudinage is common and can occur at any scale, from microscopic to lithospheric,…
How big is a Boudin in three dimensions?
In three dimensions, the boudinage may take the form of ribbon-like boudins or chocolate-tablet boudins, depending on the axis and isotropy of extension. They range in size from about 20 m thick to about 1 cm. There are three different types of boudinage. These include no-slip boudinage, s-slip boudinage, and a-slip boudinage.
How does boudinage affect the structure of rocks?
This structure suggest that both the boudinated layer and the surrounding rocks are deforming in a ductile way. However, fracturing can also play an important role in boudinage. In the example shown below, the top layer consists of strong quartz-metaconglomerate that has been boudinated within very weak phyllites (the bottom layer).