EXOGENICPROCESSES

Castañares, Angellyn

Castillo, Sofia

EXOGENIC PROCESSES or DENUDATION

> Refers to activities or phenomena that occur on the earth's surface.

> Weathering, Soil Formation, Erosion

> Related to the atmosphere, hydrosphere, biosphere

WEATHERING> This process reduces the size of rocks and prepares materials for transport.

> Different climate conditions, temperature fluctuations, and even the location of rocks affect this process.

> Mechanical & Chemical Weathering

WEATHERING: Mechanical

> The breaking down of rocks without changing their chemical composition.

> Mechanical process depend on some applied forces: a. Wind b. Water c. Gravity

WEATHERING: Chemical

> The breaking of rocks by chemical mechanisms: a. Hydration – a reaction that occurs when the minerals in a rock dissolve when they come in contact with water.

b. Carbonation – the reaction between rocks and carbonic acid formed by the dissolution of carbon dioxide in water.

c. Oxygen – may react with metal in rocks, oxidizing these metals and changing their physical and chemical properties.

SOIL FORMATION

> Soil is made up of humus which is the product of weathering and non decaying organic matter.

> Different soil types are identified based on certain factors such as the type of parent rock, climate, period of accumulation, elevation, amount of rainfall, and other environmental variables.

SOIL FORMATION

> Kinds of soil: a. Sandy - has the largest particles among the different soil types. It’s dry and gritty to the touch, and because the particles have huge spaces between them, it can’t hold on to water.

b. Silty - has much smaller particles than sandy soil so it’s smooth to the touch. When moistened, it’s soapy slick.

c. Clay soil has the smallest particles among the three so it has good water storage qualities. It’s sticky to the touch when wet, but smooth when dry.

d. Loam - It contains a balance of all three soil materials—silt, sand and clay—plus humus.

SOIL FORMATION

EROSION

> Takes place when the material is moved/transported from one place to another by natural elements such as moving water, wind, gravity, and animals.

EROSION: Water

> Running water is the most significant agent of erosion.

EROSION: Wind

> Wind is capable to transport materials from one place to another.

EROSION: Gravity

> Gravity is an agent of erosion that makes rocks to fall down from high places then causes water to flow.

> These movements, combined with soil, result in the displacement of materials down from a higher location. This process is known as mass movement or mass wasting.

Gravity: Mass Movement

> There are different mass movements, depending on the materials involved or the manner of movement.

> The slow movement of large quantities of soil over a long period is called a creep.

> On the other hand, mass movement can also be in a rapid movement: a. Landslides – rocks fall out of their places and travel along a slope. b. Mudflow – caused by landslide with a significant amount of water such as flood

Gravity: Mass Movements

EROSION: ANIMALS

> Animals can also exert an impact on erosion.