The concentration of major elements in fresh gneiss rocks (F) and weathered gneiss rocks (W) from Maitri Station, East Antarctica

Rock weathering is the breakdown and alteration of rock near the earth's
surface to produce materials that are more in equilibrium with newly imposed
physico-chemical environments. Many rocks were originally formed in earth
lithosphere at high temperature, high pressure and in the absence of air and
water. Therefore, the rock is weathered when it is exposed on the earth's
surface. Climate influences in a major way the types of weathering that will
take place in any region. In polar climate the principal weathering is
physical. Physical weathering causing the rocks to break into small fragments.
In contrast, in a tropical climate chemical weathering is very intensive. The
alteration of rocks is shown by the development of saprolites and soils. Rock
vary in the mineralogy, therefore the type of soil formed is depend on the type
of rocks.