geologic processes on earth
Post on 21-Jan-2018
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GEOLOGIC PROCESSES ON EARTH
EXOGENOUS PROCESSES
• Occur on or near the surface of Earth
• Usually influenced or driven by gravity, water, wind and organisms
• In extreme cases, it can wipe out majority of the organisms inhabiting that area.
WEATHERING
• The disintegration of rocks, soil and minerals together with other materials through contact with Earth’s subsystems
• Happens even without movement or transportation
Physical Weathering
• Breakdown of rocks by mechanical forces concentrated along rock fractures
• Can occur due to changes in temperature and pressure
• Example : soil cracks because of extreme heat or drought
• In some cases, water, wind or ice may scrape rocks or soil
Chemical Weathering
• Rocks break down by chemical reactions
• New or secondary minerals develop and sometimes replace the original properties of the minerals in the original rock or soil
• CONTRIBUTORS:
• OXIDATION – reaction of a substance with oxygen
• HYDROLYSIS – the chemical breakdown of a substance when combined with water
• ACID RAIN – may cause metals and stones to corrode or deteriorate and change their properties
EROSION
• Process by which earth’s surface is worn away by wind, water, or ice
• Moves rock debris or soil from one place to another
• Takes place when there is rainfall, surface runoff, flowing rivers, seawater intrusion, flooding, freeing and thawing, hurricanes, wind, etc.
• Movement of land animals during migration or stampede
• Human activities: deforestation, overgrazing and mining
MASS WASTING
• Movement of large masses of materials (rock debris, soil, mud) down a slope or a steep sided hill or mountain due to the pull of gravity
• Very destructive in areas with increased water flow.
• DEBRIS FLOW
• MUDFLOW
• SLUMP
Mudflow
• Happens when combined soil and water flow down a slope
• Usually happens near rivers or streams where soil or sand is always moist or has been soaked in water for a long time.
Debris flow
Happens when a large amount of sediments, usually rocks of various sizes, falls down the slope.
Does not need water to flow down
Slump
• Slow movement of soil along a curved surface.
• In time, the area would look curved because of the depression formed by the sinking land
SEDIMENTATION
• Accumulation of materials such as soil, rock fragments and soil particles settling on the ground.
• Usually occurs in streams or sea erosion
• Over time, the sediment load becomes thick and forms a new layer of ground
• If geologic processes seem to bring risk to human safety, where then is a safe place to live? Is there even any?
ENDOGENOUS PROCESSES
• Takes place within or in the interior of Earth.
• The driving force is the thermal energy of the mantle.
• Responsible for earthquakes, development of continents, mountain building, volcanic activities, etc.
MAGMATISM
• Magma is the original material that make up igneous rocks.
• Magmatism happens when a magma is generated and develops into igneous (magmatic) rocks
• The process can take place either under the surface or on the surface of Earth.
VOLCANISM (PLUTONISM)
• Process that usually happens after the magma is formed.
• Magma tries to escape from the source through openings such as volcanoes or existing cracks on the ground.
• As soon as magma reaches the surface of the earth it is now called lava.
METAMORPHISM
• Process of changing the materials that make up a rock.
• Chemical components and geologic characteristics of the rock changed due to heat and pressure that are increasing or decreasing.
• Note:
• Rocks changing due to weathering and sedimentation are not considered to have undergone metamorphism.
• What drives the endogenous processes on Earth?
• Where does the force come from?
• Why is it called endogenous?
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