<P> Collections of large rock fragments that have traveled downslope by gravity are called colluvial debris or colluvium . </P> <P> Parent materials can also be transported by wind, which includes loess and wind - blown (aeolian) sand . </P> <P> Climate is generally considered the most important factor influencing physical and chemical weathering processes . </P> <P> Physical weathering is especially important during the early stages of soil development . Rock can be disintegrated by changes in temperature which produces differential expansion and contraction . Changes in temperature can also cause water to freeze . The forces produced by water freezing can be as great as 2.1 × 10 kPa, which can split rocks apart, wedge rocks upward in the soil, and heave and churn soil material . </P>

Where can weathered parent material be found in soil