Study of intergranular films and interstitial phases in geomaterials usinghigh temperature centrifuge and ultrasonic method at high pressure

Water fluids in the Earth's crust may initiate a number of mineral reaction s resulting in different microstructure changes, which may appear in the fo rm of intergranular melt films and interstitial phases. Therefore, they hav e an essential influence on elastic wave velocities of rocks (for example, sandstone, amphibolite, basalt). The aim of the experiment was to determine the conditions of the silicate liquid and others interstitial phases distr ibution in the rock intergranular space. The results obtained using the ultrasonic method at temperature up to 950 d egrees C and under fluid pressure of 300 MPa revealed that the formation of intergranular melt films and interstitial phases network depend on chemica l composition of fluids. The experiments with use of a high-temperature cen trifuge at temperature 1400 degrees C showed that the amount of melt films, higher than 6%, is sufficient to form a system of interconnected intergran ular channels. These studies can be contributed to the petrophysical and ge ochemical interpretation of geophysical measurements. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.