Читать книгу Continental Rifted Margins 1 - Gwenn Peron-Pinvidic - Страница 34

In structural geology, boudinage refers to a deformed structure produced during the extension of a rock that is characterized by the presence of sheared rigid parts enclosed in a less competent surrounding matrix (Figure 1.23). The “boudins” correspond to pieces of the more rigid rocks that were once part of a continuous layer and have been broken into individual units, isolated laterally by anastomosing shear zones deformed in the ductile or semi-ductile stress-field. Some boudins exhibit a “pinch-and-swell” geometry. Boudinage structures can occur at all scales from microscopic to lithospheric. In rifted margin studies, it has been proposed that the continental lithosphere may deform at the regional scale under such a deformation mode. It is usually associated with specific geological settings including high thermal conditions.

Figure 1.22. Schematic illustration of the evolution of low-angle normal faults (LANFs) with the domino-block rotation model and the rolling-hinge model (source: modified from Ricketts et al. 2015)