1. Weathering: This is the breakdown of rocks, soil, and minerals through physical and chemical processes.
* Physical Weathering: This involves the mechanical breakdown of rocks into smaller pieces without changing their chemical composition. Examples include:
* Frost Wedging: Water seeps into cracks, freezes, expands, and widens the cracks.
* Abrasion: Rocks rub against each other, grinding them down.
* Thermal Expansion and Contraction: Temperature changes cause rocks to expand and contract, creating stress that can lead to fracturing.
* Chemical Weathering: This involves the breakdown of rocks through chemical reactions. Examples include:
* Dissolution: Some minerals dissolve in water, like limestone.
* Oxidation: Iron in rocks reacts with oxygen, forming rust.
* Hydrolysis: Water reacts with minerals, breaking them down.
2. Erosion: This is the transportation of weathered material from one location to another by natural forces like:
* Water: Rivers, streams, and oceans carry sediment downstream.
* Wind: Wind carries dust, sand, and other small particles.
* Glaciers: As glaciers move, they pick up and transport sediment.
* Gravity: Gravity pulls sediment downhill, causing landslides and rockfalls.
3. Deposition: As the transporting forces lose energy, the sediments settle and accumulate in a new location. This can happen in:
* Oceans: Sediment accumulates on the seabed, forming layers that eventually become sedimentary rocks.
* Rivers: Sediment is deposited in floodplains, deltas, and riverbeds.
* Lakes: Sediment settles at the bottom of lakes, creating layers that can be fossilized.
* Deserts: Wind carries sand and dust, depositing it in dunes and other landforms.
Types of Sediments:
* Clastic Sediments: These are fragments of rocks and minerals that have been weathered and eroded. Examples include sand, silt, and clay.
* Chemical Sediments: These are formed by precipitation from chemical solutions, often in water. Examples include limestone, rock salt, and gypsum.
* Biogenic Sediments: These are formed from the remains of organisms, like shells, bones, and plant debris. Examples include coal, chalk, and diatomite.
The type of sediment formed depends on the source rock, weathering processes, transportation methods, and depositional environment.
