R. J. Knipe, 1986. "Microstructural evolution of vein arrays preserved in Deep Sea Drilling Project cores from the Japan Trench, Leg 57", Structural Fabrics in Deep Sea Drilling Project Cores From Forearcs, J. Casey Moore
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The geometry and microstructural features of veins preserved in D.S.D.P. cores from Leg 57 (Japan Trench) are described, based on a combination of optical and transmission electron microscopy. The veins represent a localized failure and show a range of geometrical patterns, which may relate to the strain rate history involved in their evolution. The microstructures associated with the veins are complex and indicative of a range of strain paths. Disaggregation and grain boundary sliding (particulate flow) are the most important processes involved in vein development. It is suggested that (i) although a high pore fluid pressure would aid the initiation of the veins, alternative mechanisms of failure, including collapse during shearing, are also possible, and (ii) the preferred alignment of grains within the veins was probably not formed by “streaming” fluids but by rotation during the porosity reduction and slow fluid expulsion late in the history of vein development. The larger-scale implications of veins are discussed; the range of strain paths associated with veins is suggested to arise from the location of veins in a complex down-slope movement system.