Erosion is a natural process that wears away bits of Earth and transports them across space, often many miles from where they were first eroded. Erosion causes small pieces of rock and soil to move over distances which might otherwise remain unchanged.
Physical erosion occurs when water seeps into cracks in rocks and ice, known as “ice wedging”, widening and deepening them over time.
Weathering
Water is one of the primary forces shaping Earth’s landscape, acting to erode rock debris (sediment) and organic materials (compost). As it does so, its erosion creates soil layers which form an intermediate zone between biosphere and geosphere that provide support for life while storing minerals.
Weathering of bedrock produces sediment when small particles, known as clasts, break away and are transported and deposited as weathered debris. While most clasts begin with sharp edges, during erosion the corners are worn down or rounded off resulting in easier transport and deposit of well-rounded particles than their more angular counterparts. When compacted together over time sedimentary rocks such as sandstone can form.
Chemical and mechanical weathering work hand in hand to enhance each other’s effects, reinforcing each other’s effects. Chemical weathering only takes place on rock surfaces, while mechanical weathering provides more surface area for chemical weathering to take place on. Different rates of erosion create unique geological features like Grand Canyon’s cliffs or Bryce Canyon’s hoodoos; salt expansion (similar to frost wedging) also plays a part.
Erosion
Erosion is the natural process by which rocks and earth are worn away by wind, gravity, water, or ice forces and transported from one location to the next. Erosion’s main causes include gravity, wind, water and ice forces.
Physical erosion refers to any change in shape and size of rock without altering its basic chemical makeup, often along coastlines where waves break pebbles into sand, gradually wearing away at beach cliffs and wearing away at pebble beds. Furthermore, water and sand seep into streams, rivers, lakes and floodplains where it helps form valleys, shape mountains and fill floodplains with sediment and minerals.
Plants contribute to physical erosion by dislodging soil as they grow, while plants, glaciers, and living organisms accelerate it by picking up particles off surfaces and carrying them away. Different rock types also vary greatly in their resistance to erosion – leading to distinct geological features like those seen at Bryce Canyon National Park and Goblin Valley State Park in Utah – such as their respective hoodoos.
Deposition
River energy breaks away at its bed rock, leaving behind sediment which then gets carried downstream until enough kinetic energy has been lost for it to deposit properly – this process is called deposition.
Geologists use sediment type to help them interpret weathering and transport processes that created it, such as well-rounded sediment that’s free from angular corners; such an indicator indicates longer distance travel or more active erosional processes.
Chemical weathering occurs most often where there is access to sufficient water, which helps break apart rocks through chemical reactions. Minerals with higher crystallization points (like quartz) tend to be less vulnerable to this form of degradation than minerals lower on the Bowen reaction series (such as olivine and pyroxene). Deep underground waters often undergo greater pressures and temperatures which make it more prone to chemical weathering; once emerging back onto the surface it may leave deposits of chert behind.
Impacts
Water is one of the primary factors influencing weathering and erosion, and plays a pivotal role in sedimentary rock formation. It possesses unique properties that allow it to both act as a chemical weathering agent as well as transport and deposit sediments.
Mechanical and chemical weathering work hand in hand, with mechanical weathering having an influence on chemical weathering rates. Mechanical weathering breaks up rocks into smaller pieces to increase surface area available to chemical weathering; warmer environments tend to experience faster rates of both mechanical and chemical weathering processes.
The composition and characteristics of soil depend on five main elements: mineral composition of bedrock, topography, climate, weathering and organic matter. Organic matter includes plant roots, fungi and other organisms which add organic material to soil; water minerals and atmospheric gases also comprise part of its makeup; flow from natural and engineered conveyances (such as rivers roads and dams) can affect erosion and deposition processes in different ways – faster-eroding rivers can carry away more sediment more rapidly resulting in alluvial fans and deltas being formed by this process than gentler landscapes can do; this process creates alluvial fans and deltas among many features shaped by these processes such as alluvial fans and deltas being formed.