Earth Science Exogenic Processes
Water Wind Glacial Ice Gravity
agents of erosion
exfoliation dome
an example of Sheeting/ exfoliation/ unloading is __
talus
during frost wedging the rocks that pile up at the bottom of the cliff into large lakes are called __
Carbonation Oxidation Hydrolysis Hydration Solution
examples of chemical weathering
Carbonation
mixing of water with carbon dioxide to make carbonic acid; Primarily occurs in wet and moist climates
solution
process by which the rocks are dissolved when exposed to rainwater; Usually happens in limestone and gypsum
biological weathering
weakening and subsequent disintegration of rock by plants, animals and people; Ex: mining; both chemical and physical weathering
abraision
Caused by rubbing and or bouncing of rocks with each other while they are transported by water, wind, glacial ice, or gravity
Hydration
Chemical combination of water molecules with a particular substance or mineral leading to a change in structure.
Hydrolysis
Chemical reaction between hydrogen ions and minerals
Chemical weathering
Decomposition, dissolution, alteration, of rock through chemical action
Weathering Erosion Mass waste Deposition
Earth's external processes
Mass wasting
Transfer of rock and soil downslope primarily by gravity
Erosion by water (fluvial)
Water erodes rocks and landscapes by transporting weathered materials from their source to another location where they are deposited
Salt crystal growth
Water with dissolved salt accumulates in these spaces and then evaporates and growing salt crystals wedge rocks apart; Occurs when salts crystallize out of the solution as water evaporates; Most common in dry climates like deserts
Frost Wedging
When water freezes it expands by about 9% and exerts tremendous force; This force breaks off rocks, tumble and pile up at the bottom of the cliff into large lakes
Erosion by wind (aeolian)
Wind erodes weathered rocks by picking them up and temporarily transporting them ; ex: sand dune
Physical / mechanical weathering Chemical weathering Biological Weathering
2 Types of Weathering
Thermal expansion or contraction/ block disintegration
Granular disintegration Differential thermal expansion and contraction if individual mineral grains in coarse crystalline rocks; Common in desert climates
Oxidation
Occurs when oxygen and water react with iron rich minerals which weakens the rock ex: rusting
Erosion by ice (glacial)
Particles are incorporated into the glacial ice through a process referred as picking
Weathering
Physical disintegration and chemical alteration of rocks at or near the earth's surface
Physical weathering
Physical disintegration and reduction in size of the rocks without changing in chemical composition
Erosion
Physical removal and transportation of weathered material by mobile agents such as water, wind or ice and gravity
Frost wedging Salt crystal growth Sheeting/ exfoliation/ unloading Thermal expansion or contraction/ block disintegration Abrasion
Physical/ mechanical weathering examples ()
Deposition
Process by which weathered and eroded materials are laid down or placed in a location that is different from their source
External / exogenic processes
Processes that occur at or near the earth's surface and powered by the energy from the sun
Internal / endogenic processes
Processes that occur underneath the earth's surface and are powered by the forces from within the Earth
External / exogenic processes
Produce changes to the landscape that influence surface and subsurface topography and landform development ; The processes lead to transformation of rocks
Sheeting/ exfoliation/ unloading
Reduced process in igneous rock causes it to expand in sheets; Because of pressure because of the uplift of rocks, the rock peel into sheets
Erosion by gravity
The downslope transportation if loosened, weathered materials and enables them to move without the aid of water, wind or ice; may be slow or abrupt; Unconsolidated materials stabilize near an angle of 35 degrees (angle of repose)
Water Oxygen Carbon dioxide
The most important agents/ catalysts of chemical weathering