Correlations between compressional and shear wave velocities and corresponding Poisson's ratios for some common rocks and sulfide ores

摘要

The correlations between V-p and V-s and corresponding Poisson's ratios are important in modeling and interpreting seismic data in terms of chemistry and lithology. Data from high-pressure laboratory measurements of compressional and shear wave velocities (V-p and V-s) are analyzed for 12 common categories of rocks (amphibolite, anorthosite, basalt, diorite, eclogite, felsic gneiss, gabbro-diabase, granite, intermediate gneiss, limestone, mafic gneiss, and peridotite) and 4 types of massive sulfide ores (chalcopyrite, pyrite, sphalerite and pyrrhotite). The analysis reveals that the linear correlation provides good descriptions for the V-s-V-p and InVs-InVp relationships. Poisson's ratio is linearly correlated with V-s, V-p, shear modulus (G) and Young's modulus (E) for these rocks and sulfide ores. A decrease in Poisson's ratio is associated with increases in V,, G and E. However, the variation of Poisson's ratio with V-p depends on the logarithmic ratio R-s/p(i.e., partial derivative InVs/partial derivative InVp). Poisson's ratio increases or decreases with V-p when R-s/p< 1 or > 1. R-s/p, varies systematically with lithology (0.300 for granite, 0.573 for diorite, 0.602 for felsic gneiss, 0.631 for intermediate gneiss, 0.721 for gabbro-diabase, 0.768 for mafic gneiss, 0.866 for eclogite, 0.890 for amphibolite, and 1.391 for peridotite). It is suggested that R-s/p can be used as a proxy for the composition of the deep continental crust and the upper mantle.