Inhaltszusammenfassung

The development of delta-type porphyroclasts was modelled experimentally in a circular transparent shear rig using crystalline rock analogue materials. Rectangular camphor objects embedded in a matrix of octachloropropane were deformed in simple shear flow. The camphor deformed into delta-objects with progressive deformation up to a shear strain of 100. The development of these delta-objects and of gradients of flow parameters in the matrix was followed from step to step during the deformatio...The development of delta-type porphyroclasts was modelled experimentally in a circular transparent shear rig using crystalline rock analogue materials. Rectangular camphor objects embedded in a matrix of octachloropropane were deformed in simple shear flow. The camphor deformed into delta-objects with progressive deformation up to a shear strain of 100. The development of these delta-objects and of gradients of flow parameters in the matrix was followed from step to step during the deformation. The delta-objects in this experiment show stair-stepping of wings that did not occur in earlier experiments with Newtonian fluids. Analysis of the flow pattern indicates that this is due to an unusual flow perturbation geometry around the relatively rigid camphor objects which rotate more slowly than equivalent objects in Newtonian flow. The non-Newtonian theology of the experimental materials may be responsible for this deviant behaviour. This implies that non-Newtonian fluids are better analogues than Newtonian fluids to study the development of structures in rocks with non-Newtonian theology, since the geometry of the resulting structures can be different.» weiterlesen» einklappen

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DDC Sachgruppe:
Geowissenschaften