Water, wind, ice and gravity wear away at rock, soil and other geological materials through erosion; the pieces eroded away are carried away to be deposited elsewhere as layers of sediment.
Deposition occurs when the transporting agent (such as wind or water) loses enough kinetic energy to allow particles to settle out and settle onto the bottom surface. Factors influencing deposition include size, shape and density of sediment particles.
Erosion
Erosion is the natural process of wearing away and transporting rocks, soil and other geological materials from one location to another. Erosion results from weathering processes caused by natural forces like water, wind and gravity.
Streams and rivers erode land as they move downstream, carving river valleys and increasing floodplains. Waves also erode seashores leaving behind rock stacks or caves as their wake travels along the coastlines, while wind erosion picks up particles of dust, sand and silt in its wake.
Erosion increases with rainfall. Heavy, energetic rainfall from thunderstorms or other natural sources such as floods can increase erosion rates on hillslopes by way of rain splash and wind erosion, or accelerate it in areas where movement of water is accelerated or where material deposits through natural agents such as floods – for instance floodwaters may accelerate erosion rates on hillslopes by depositing silt and sand deposits suddenly onto surfaces like beaches and riversides.
Deposition
Erosion causes bits of rock and soil to be carried away and must find somewhere to settle, usually through wind or water currents.
Competence refers to the force that transports particles, and depends on a delicate balance between forces that affect erosion media – this includes particle size, shape and velocity.
Erosion creates landscape features that define our land. Rivers erode and deposit sediment as they flow downstream, producing waterfalls, floodplains, meanders and alluvial fans along their course as well as deltas and alluvial fans created by streams; caves form when water slowly dissolves rock; while ocean waves erode and deposit materials along their coastlines.
Streams
Deposition occurs when a river empties its load of sediment into standing waters such as lakes or oceans after flowing for many kilometers, leaving behind gravel and silt that forms into triangular-shaped deposits called deltas.
Streams erode rocks and transport the debris downstream, known as bed load material. Furthermore, streams dissolve materials they take in from their environment such as saltwater that makes up an ocean’s saltiness; these substances make up its “dissolved load”.
Streams typically flow along meanders, which are series of curves and bends shaped like riverbanks. Over time, outside curves of a meander erode faster than its interior curves, leading to its migration laterally over time.
Waterfalls
Waterfalls are stunning natural wonders that evoke feelings of amazement and respect. Most waterfalls consist of freshwater from rivers, streams or glaciers.
Rivers often carry solid material known as sediment through their stream beds. This may range from microscopic silt particles to larger pebbles and boulders; as these materials accumulate they can wear away the soft rock that makes up a river bed and alter its channel over time.
Waterfalls are the result of erosion from rivers or streams flowing over steep rock ledges into plunge pools below, typically along rivers or streams. Waterfalls may form horizontally or vertically; some styles such as curtain waterfalls or punchbowl waterfalls even allow them to take unique shapes like curtains and punchbowls.
Glaciers
Glaciers are vast rivers of ice that flow down mountains into valleys, serving as vital water sources for communities downstream.
Gravity drives glacier movement and structure is composed of water molecules bound loosely together by their loose bonds; however, if any obstacles or forces under the glacier outstrip these ties too strongly then its layers may break apart and separate from one another.
Glacier movement can create cirques, or bowl-shaped ridges that gradually transform into mountain sides, as well as aretes – sharp peaks formed when two cirque glaciers meet and begin eroding each other’s cliff walls.
Glaciers can scour rock from bedrock surfaces, leaving behind long gouges known as chatter marks that mark both speed and direction of glacier movement.