Amount Water Rocks at www.japanese-home-gardens.com

The three factors of prime importance in determining the manner in which rocks will respond under heat and pressure are the original composition of the rocks, the temperature attained during metamorphism, and the pressure of the water vapor contained in the rocks, especially in relation to hydrostatic pressure or depth. Temperature is the great driving force in regional metamorphism, but the new mineral assemblages resulting from it are largely determined by the rocks' original composition and the amount water rocks of water enclosed in them. It has been said that regional metamorphism is contact metamorphism on a regional scale. This is especially true in the deeper parts of the crust.

Another recently discovered method involves measuring the amount water rocks of water the rocks contain. Under strain, the pores in the rock enlarge, allowing more water to enter. Because of the importance of ground water in producing earthquakes, knowledge of the water level in wells in earthquake-prone areas is extremely valuable.

Aquicludes. The pores in some rocks are quite small, so that water is held in them by molecular forces. Such rocks, which preclude or retard the movement of water through them, are called aquicludes or aquitards. Among such rocks are clay, clay mixed with sand or gravel, shale, silt, glacial till, and weathered residual rocks.