Weathering and Formation of Soil

Exam Prep Study Notes (Things to remember) 


Weathering

  • Mechanical weathering breaks existing rock into smaller pieces without changing the composition of the rock.
  • Ice wedging and abrasion are two important processes of mechanical weathering.
  • The main agents of mechanical weathering are moving water, wind, glacial ice and gravity.
  • Chemical weathering decomposes or breaks down existing rock, forming new minerals that are stable at the Earth's surface.
  • Water, carbon dioxide, and oxygen are important agents of chemical weathering.
  • Different types of rocks weather at different rates. More resistant types of rocks will remain longer.

Soils

  • Soil is an important resource. Life on Earth could not exist as it does today without soil.
  • The type of soil that forms depends mostly on climate but to a lesser extent on original parent rock material.
  • Soil texture and composition plus the amount of organic material in a soil determine a soil's qualities and fertility.
  • Given enough time, existing rock will produce layers within the soil, called a soil profile.
  • Ultimately, the climate of a particular region will produce a unique type of soil for that climate.