1. Weathering: This is the breakdown of the rock into smaller pieces. There are two main types of weathering:
* Physical Weathering: This involves the physical forces that break down rocks without changing their chemical composition. Examples include:
* Frost Wedging: Water freezes in cracks, expands, and widens the cracks.
* Thermal Expansion/Contraction: Large temperature swings cause rocks to expand and contract, weakening them.
* Abrasion: Rocks grind against each other, breaking them down.
* Chemical Weathering: This involves chemical reactions that alter the composition of the rock. Examples include:
* Dissolution: Acids (like rainwater with dissolved carbon dioxide) dissolve some rocks (like limestone).
* Oxidation: Oxygen reacts with minerals in rocks, changing their composition.
* Hydrolysis: Water reacts with minerals in rocks, changing their composition.
2. Erosion: This is the process of transporting the weathered rock fragments. Agents of erosion include:
* Water: Rivers, streams, and waves carry sediment downstream.
* Wind: Wind picks up and carries small sediment particles.
* Ice: Glaciers carve out valleys and transport large rocks.
* Gravity: Gravity pulls rocks and sediment down slopes.
3. Deposition: This is the process of the sediment being dropped in a new location. As the erosive force loses energy, it can no longer carry the sediment, causing it to settle.
4. Lithification: This is the process of sediment turning back into rock. This involves:
* Compaction: The weight of overlying sediment compresses the lower layers, squeezing out water and air.
* Cementation: Dissolved minerals in groundwater precipitate between the sediment grains, binding them together.
In Summary: A newly formed rock goes through a cycle of weathering, erosion, deposition, and lithification to become sediment. This cycle is part of the rock cycle, which is a continuous process of transformation between different types of rocks.
