Small-scale boudinageBoudinaged quartz vein within blueschist, Samos, Greece.Boudinage in Greenland near KangerlussuaqBoudinaged quartz vein in shear foliation, Starlight Pit, Fortnum Gold Mine, Western Australia.Banded gneiss with dike of granite orthogneiss; competent banded gneiss is boudinaged by ductile shear.Boudin on the Island of Uto, Stockholm Archipelago, SwedenChocolate-tablet boudinage structures in a low grade metasedimentary rock outcropping in Deception Pass, Washington
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 is common and can occur at any scale, from microscopic to lithospheric, and can be found in all terranes.[2] In lithospheric-scale tectonics, boudinage of strong layers can signify large-scale creep transfer of rock matter.[2] The study of boudinage can also help provide insight into the forces involved in tectonic deformation of rocks and their strength.[2]
Boudinage can develop in two ways: planar fracturing into rectangular fragments or by necking or tapering into elongate depressions and swells.[3] Boudins are typical features of sheared veins and shear zones where, due to stretching along the shear foliation and shortening perpendicular to this, rigid bodies break up. This causes the resulting boudin to take a characteristic sausage or barrel shape. They can also form rectangular structures. Ductile deformation conditions also encourage boudinage rather than imbricate fracturing. Boudins can become separated by fractures or vein material; such zones of separation are known as boudin necks.[3]
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.[4]
^Fossen, H. (2010). Structural Geology. Cambridge University Press. p. 272. ISBN 978-0-521-51664-8.
^ abcMarques, Fernando O., Pedro D. Fonseca, Sarah Lechmann, Jean-Pierre Burg, Ana S. Marques, Alexandre J.M. Andrade, and Carlos Alves (2012). "Boudinage in Nature and Experiment." Tectonophysics 526-529, 88-96.
^ abArslan, Arzu, Cees W. Passchier, and Daniel Koehn (2008). "Foliation Boudinage." Journal of Structural Geology, 30 (3), 291-309.
^"Boudinage." Encyclopædia Britannica (2010). Encyclopædia Britannica Online. 06 Oct. 2010 <http://www.britannica.com/EBchecked/topic/75420/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...
Those rich in clay may show stretched clay lumps (a phenomenon called boudinage) and zones of concentrated shear. Debris flow deposits take the form of...
inclusions in shear zones, deformation of early lineations, chocolate tablet boudinage and evolution of shear zone structures. A theory on conglomerate deformation...
strength layer within more rigid silicate sedimentary rocks. As such, boudinage structures, dikes of sulfides, vein sulfides and hydrothermally remobilized...
observed in rocks using all these techniques since the early 1900s. The Boudinage experiments show that localized plasticity is observed in certain rock...
the finite strain axes. Although structures like asymmetric folds and boudinages are also related to the orientations of the finite strain axes, these...
been transferred into the Indus-Yalu suture zone, as well as large scale boudinage. Research in the early 1990s suggested that this slip was transferred...
sandstone is stretched and deformed amidst less competent beds. See also boudinage. boulder Bowen's reaction series The sequence in which minerals crystallize...
by tectonic stresses at the formation of the Appalachians) —— (1947). "Boudinage". Transactions, American Geophysical Union. 28 (4): 626. Bibcode:1947TrAGU...
appearance, foliation, preferred orientation of biotite crystals, faults, boudinage, plagioclase with bent twin lamella; feldspar with peristherite, plagioclase...
Approaching the CUU body, the lineation breaks down into a zone of heavy boudinage and oblique shear with a pronounced C-S shear fabric, especially in the...
the high strain zone include pressure solution, dilational veins and boudinage. Some of the rock appears as mylonite. Underneath the high strain is chert...
dolomite and boulder conglomerate are also included. The complex includes boudinage structure and en echelon veins. Phyllite near Strathgordon has been dated...
Internally it is characterized by a through gut flanked by a pair of boudinaged tubes interpreted as nephridia ("kidneys"). Its trunk is adorned with...
bounce castes, ripple lamination, graded bedding, cross bedding, and boudinage. The shale layers have been identified as Association IV in the submarine...
Neoproterozoic paragneis of the Arverne domain near Nontron, Dordogne. The light-coloured graywacke layer is boudinaged and dips steeply to the NNE....
1982). "The effect of material properties on growth rates of folding and boudinage: Experiments with wax models". Journal of Structural Geology. 4 (2): 215–229...
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