Compare temperature and pressure conditions on the Earth's surface to those below the Earth's surface, and relate these conditions to the process of lithification.
The temperature and pressure on the earth's surface is lower than that below the earth's surface. Generally, temperature and pressure increases as you move/dig down the earth's surface. This increase in temperature and pressure causes the earth's sediment (below the earth surface) to form a compact solid rock - this process is known as lithification.
