To identify the physical properties responsible for the seismic reflections from the deep ductile shear zones, we have undertaken a study on the effect of lattice preferred orientation (LPO) on the seismic velocity an...
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To identify the physical properties responsible for the seismic reflections from the deep ductile shear zones, we have undertaken a study on the effect of lattice preferred orientation (LPO) on the seismic velocity anisotropy. LPO has been quantitatively determined by U-stage measurement for plagioclase (An 49), diopside and hornblende from an extensively deformed basic mylonite from Jotun Nappe, Norway. The typical plagioclase fabrics are produced by plastic flow on (010) [001], and the normal diopside and hornblende fabrics are produced by (100)[001] slip. The complete seismic properties (VP, VS, VSS and △VS) with respect to structural frame (foliation and lineation) have been calculated for hypothetical monomineralic and polymineralic aggregates from the elasstic stiffness coefficients and LPO data. The calculations show that the strongest Vp anisotropies develop in monomineralic rocks with values between 5% and 14%, compared with 5.6% and 7.8% for granulite (50% P1, 50% Di) and amphibolite (50% P1,
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