Exogenic processes Flashcards
External processes invlolves?
Mass wasting, erosion, and weathering
physical breakdown
(disintegration) and chemical alteration
(decomposition) of rocks at or near the Earth’s
surface.
Weathering
physical forces that break
rock into smaller and smaller pieces without
changing the rock’s mineral composition.
Mechanical Weathering
Causes of mechanical weathering?
Biological activities, human activities, salt crystal growth, Frost wedging, and expansion resulting from unloading
A rock unit buried below a land surface experiences high compressional stresses because of the weight of the overlying rock.
Expansion resulting from unloading
Process of splitting igneous rocks into onion like sheets
Exfoliation
weakening and subsequent disintegration of rock by plants, animals and microbes.
Biological activities
process is physical, the
pressure is exerted by a biological process
Biological activities
External Processes are those processes that
occur at or near the Earth’s surfaces and are
powered by the energy from the sun.
Exogenic processes
Such as digging, blasting, strip mining and agriculture
human activities
basic part of the rock cycle, thus, a key process
in the Earth system.
weathering
These fractures divide the rock into a series of layer or sheets
Sheeting
High temperatures in desert environments also tend to promote weathering caused by the crystallization of salts in pore fractures
salt crystal growth
Disruption of rock fabrics owing to stressed generated by freezing and thawing of water in rock fracture.
Frost wedging
chemical transformation of rock into one or more new compounds.
Chemical weathering
certain minerals dissolved in water
Dissolution
water is being absorbed into the crystal structure causing them to expands
Hydration
occurs when water reacts with minerals and breaks them down.
Hydrolysis
occurs in plants, fungi and lichens secrete organic acids that dissolve minerals and the nutrients are taken by these organisms
Biological weathering
when carbon dioxide interacts chemically with minerals
Carbonation
the reaction of oxygen with minerals in the rock that forms oxides
Oxidation
control weathering by their physical and chemical reaction to climate.
Rock type
speed at which rock or soil is broken down.
Rate of weathering
affects the rate of weathering because if you have rough steep slopes, there is more area expose to rain, wind
Topography
controls weathering because the rate of chemical reactions doubles with every 10 °C rise.
Climate
process by which sediments are moved along from the source to where they are deposited
Transport
Very fine dust or slit
Loess
the picking up of loose materials from the
Earth’s surface.
Deflation
sand blasting process that occurs as material is carried along with wind.
Wind abrassion
A rock’s exposure to the weathering elements and
its surface area can affect its rate of weathering.
Surface area
Control rate of weathering (4)
Surface area, topography, climate, and rock types
the separation and removal of weathered
and unweathered rocks and soil from its substrate due to gravity of transporting agents like wind, water, and ice
Erosion
occurs commonly in flat, bare areas of dry, sandy and lose soils. It detaches particles and transport them by wind.
Wind erosion
Low mound or ridge of sediments
Dunes
Sand dunes in Paoay Ilocos Norte are formed through this process?
Dunes
The most common erosional agent.
Water
Permanent body of ice, consist of recrystallized snow and show evidence of movements through gravity
Glaciers or ice
the rolling or dragging of large grains aided by
the push of smaller grains.
Traction
moving of particles
Suspension
movement of soluble materials.
Solution
bouncing of sand grains as they are picked up,
carried along, and dropped repeatedly.
Saltation
Term for sediments by glacial origin
Glacial drift
produced when mass wasting and running water combines
Steam valley
an event that initiates downslope movement
Trigger
downslope movement of rock, regolith, and soil under the direct influence of gravity. It does not require a transporting medium.
Mass wasting
controlling force of mass wasting is?
Gravity
steepest angle at which a material remains stable
Angle of repose
process where water-saturated surface material loses their strength and behave as fluid-like masses that flow
Liquefaction
a massive debris flow.
Mudslide
Formed or occurring on the surface of the
Earth
Exogenic
