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. [1] The competent bed begins to break up, forming sausage-shaped boudins.

Boudinage. Top: boudins; bottom: chocolate tablet structure. Buckle folds are formed when strong (or ‘competent‘) layers of rock are shortened. What happens when strong layers are extended? Typically the layers start to thin at points of weakness (a process known in engineering as necking) producing a structure called pinch-and-swell.

Boudins come in different shapes (Fig.3), depending on how they behaved during deformation. The different shapes relate to the competence contrast across the boudinaged layer and its two side, and of the type of fracture that forms (extension or shear fractures).

• Fold and boudinage structures – Boudinage is a structure produced during he extension of competent layers enclosed in an incompetent matrix

Boudinage structure consists of a periodically pinched or segmented rock layer or vein enveloped within a rock of a different kind (Figs. 1, 2). Boudin means sausage in French because deformed sandstone beds at Bastogne were originally compared to sausages lying side by side ( Lohest, 1909 ; Lohest et al., 1909 ; cf. Wilson, 1961 , p. 496).

2019年5月19日 · Boudinage is a very common structure which helps the geologist understand ‘who is stronger than who?’ and helps them guess the physical conditions at which deformation took place. Boudinage style can also vary enormously. For example, the eye-shaped boudins shown at the top of the page are called ‘pinch-and-swell’ structures.

They are excellent structures for learning the measurement of linear and planar structures. Geometric and morphological parameters of the boudins allow drawing conclusions about several structural parameters, such as, kinematics. vorticity, strain rate and shear strain. 2. Methodology Data Record Boudin Type Boudin Simmetry Flow Type.

Boudins form when lengthening affects a layered rock formation involving competent layers embedded into a less competent, easily deformable, host rock. Upon extension, the stronger layers lengthen via heterogeneous thinning leading to the development of pinch and swell structures (i.e. thinning of the strong layer is periodic).

In the present study, we carried out measurements of natural boudins and experimentally tested the effects of two variables on boudinage: layer thickness and compression rate.

2012年3月10日 · The study of boudinage is of great relevance to geosciences because: (1) it can occur at all scales, from microscopic to lithospheric; (2) it is very common and has been observed in all terranes under a very wide range of pressure/temperature/fluids conditions; (3) it is of major significance for lithospheric-scale tectonics because, at this ...