Earth’s Surface was formed from a variety of geologic processes

Constructive vs. Destructive Constructive force – processes that build up Earth's crust, create new landforms, or add sediment to existing areas of land Destructive force – processes that break down rocks and landforms and carry sediment away

Weathering Process by which rock materials are broken down 2 kinds Mechanical Weathering Chemical Weathering

Mechanical Weathering Breakdown of rock into smaller pieces by PHYSICAL means Ex: Ice, wind, water, gravity, plants, animals

Chemical Weathering The process by which rocks break down as a result of CHEMICAL reactions Ex: Water, Acid Precipitation, groundwater acid, acid in living things, air

Erosion The process by which soil and sediment is transported from one location to another

Deposition The process by which sediments are released (dropped).

Agents responsible for Weathering, Erosion, and Deposition Running Water (Streams and Rivers) Moving Ice (Glaciers) Ocean Waves Wind Mass Wasting (Huge amounts of rock/sediment moving downhill)

Streams and Rivers Erosion starts upstream and deposition happens downstream Sediment is smooth because of weathering (water rolling over the sediment) Young rivers have faster erosion Mature Rivers have more deposition Deposition happens mostly at mouth of ocean/lake and inside bends of rivers/streams

Factors Making Faster Erosion Shape of channel – Narrow and V shaped Gradient (Slope) – Steep Velocity (Speed) - High

Factors Making Deposition Faster Shape of Channel – Wider Gradient (Slope) – Gentler Velocity (Speed) - Low

Floodplains A nearly flat expanse of land that stretches from the banks of a slow, meandering river

Glaciers’ Erosion Glacier - a large body of snow and ice that forms on land and does not melt annually Creates U shaped valleys Smooth bedrock beneath and on sides of valley Rocks trapped in glacier cut lines into bedrock

Depositional Features of Glaciers Moraines – deposit of sediment that forms at the edge of a glacier as it pauses Till – Sediment directly deposited by glacial ice as it melts

Depositional Features of Glaciers Drumlins – Hills molded from till by glaciers moving over it Outwash Plains – Broad, flat area in front of a glacier where large amounts of sediment are deposited by glacial melt water

Depositional Features of Glaciers Kettles – Large depression left when ice melts Kettle lakes form when water wills the depression Erratic – a rock or boulder that differs from the surrounding rock and is believed to have been brought from a distance by glacial action

Depositional Features of Glaciers Eskers – A long, narrow, winding ridge composed of sand and gravel deposited by a glacier.

Weathered Features of Ocean Waves Cliffs – A vertical, or near vertical, rock exposure Sea Stacks – landform consisting of a steep and often vertical column or columns of rock in the sea near a coast.

Erosional and Depositional Features of Ocean Waves Beach – Sand is deposited by waves Spits - A depositional landform found off coasts where at one end, spits connect to land, and extend into the water

Erosional and Depositional Features of Ocean Waves Barrier Islands – a coastal landform and a type of barrier system, are exceptionally flat and lumpy areas of sand, that are parallel to the mainland coast

Wind Weathering, erosion, and deposition by wind is common in: Arid reqions with no veggitation so sediment is exposed. Along costal regions where wind is active Deserts where sandblasting occurs

Wind Landforms Yardangs -  A hill carved from bedrock by the dual action of wind abrasion, from dust and sand Unique Rock Textures Dunes – Hills formed by deposition of sand Along coasts and in deserts

Erosion and Deposition from Mass Wasting Materials such as rock and sediment move downhill because of gravity Threat to humans and their property Mass wasting can be: Dry or wet Slow or fast Large chunks or small particles

Erosion and Deposition from Mass Wasting Avalanches – a rapid flow of snow down a sloping surface Soil Creep – the slow downward progression of rock and soil down a low grade slope

Erosion and Deposition of Mass Wasting Mudslides – a rapid movement of a large mass of mud formed from loose dirt and water Rockfall – quantities of rock falling freely from a cliff

Erosion and Deposition of Mass Wasting Landslides - the sudden movement of large amounts of loose soil, rocks, and other materials as they fall or slide downward due to gravity