Hyun, composition. Physical weathering of rocks occurs largely

Hyun,
Jung

Geography
5

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Professor
Drake

11
Dec 2017

The Mechanic of Physical Weathering

 

When the paper is old, it turns
yellow color, and when the car is peeled off, it rusts. In addition, the
appearance of the old stone statue is not clear, and the letters engraved on
the surface of the old monument can be seen to be blurred. Why is this
happening? As the stone statue or monument becomes blurred in the form of the
outer surface over a long period of time, the rocks near the surface gradually
change or break down over long periods of time with water, air, and biological
action. Physical weathering is the act of breaking down rocks on the
surface by physical factors such as pressure and temperature changes. Weathering
is an event where rocks near the surface are split into smaller pieces, or
minerals in rocks change their constituents through the contact of water and
air. Also, weathering has physical or mechenical weathering that rocks are
broken by physical force, and chemical weathering which changes rock
composition. Physical weathering of rocks occurs largely by water material, and
the weathering state is influenced by the nature of the parent rock, the
climate, the presence of soil, the exposure time of the rock in the atmosphere,
and topography. Rocks are differently dissolved or crumbled depending on the
type and structure, and the weathering speed varies depending on the types of
minerals. Also, climate which is indicated temperature or precipitation affects
weathering. In dry and cold places, there is little water that can dissolve
some of the components of the rock, and there are many times when it is
freezing, so the effect on the chemical weathering is relatively weak. On the
other hand, as the water freezes and becomes ice, physical cracking of the rock
by the force can be promoted. The base material generated by the physical
weathering of the rocks will remain on the parent rock for many years or will
be moved to a new place by natural forces such as air and water and develop
into soil. These called a residual material or a transported parent material.
Physical weathering is done through the following process.

All of those processes break off
tiny items of rock that will fall and accumulate at the bottom of outcrops
forming talus slopes. In the highest mountains in Hawaii, the freeze or thaw
cycle is nearly a daily incidence and therefore frost wedging is kind of
active. Perennial cycles produce a curious sorting of rock fragments into rows
referred to as stone stripes. On a bigger scale, if an especially significant
weight, like associate ice sheet, is off from a rocky region, the complete
space can expand upwards as pressure is mitigated, occasionally forming
exfoliation domes, during which the surface rock breaks off in sheets.

            Most
common style of physical weathering is ice or frost wedging. Frost wedging may
be a natural results of the very fact that water expands once it freezes. If
water gets into a fracture in an exceedingly rock and freezes, it will expand
and place pressure on the rock from inside the fracture. Over time, sequential
cycles of phase transition and thawing will cause this fracture to expand.
Eventually, a chunk of the rock is also broken off on this fracture. Similarly,
root wedging is that the method by that a plants scheme grows into existing
fractures and expands these fractures because the roots grow. Thermal growth
describes the consequences of heating and cooling on a rock. Over the course of
each day, week, year, etc. a rock is heated and cooled repeatedly if exposed to
the weather. It takes into account an outcropping in an exceedingly moderate
climate. Throughout the day, this rock is exposed to daylight, step by step
heating the rock and inflicting it to expand. Because the temperature drops
long, the rock begins to cool down and contract. Moreover, the rock might not
be uniformly heated or cooled reckoning on its orientation and a range of
different factors. The perennial heating and cooling places stress on the rock
which may cause it to fracture and break. This could happen as a result of
existing fractures within the rock square measure exacerbated, or as a results
of minerals responding otherwise to the heating and cooling with an ensuing
fracture on the natural mineral boundaries within the rock.

Occasionally, material
disentangled by physical weathering processes slips downward by gravity alone
as a landslide. For our functions, the word landslide may be a general term for
the movement of loose rock and soil down slope, which incorporates rock falls,
rock slides, earth flows, debris flows or slides, and soil avalanches. The
movement could occur suddenly, as a slope failure, or creep downward slowly
over several days, months, or maybe years. In Hawaii, landslides are available
all sizes, from small ones that scar the hillsides to the most important
familiar collapses on planet Earth. Moreover, the fourth main style of physical
weathering results from unloading. It happens once superimposed material,
corresponding to soil or another rock stratum, is removed (most unremarkably
through erosion) and confining pressure on the underlying rock is shrunken. In
response, the rock typically fractures into sheets that lie perpendicular to
the direction within which pressure is discharged. Since the foremost common
prevalence is that the removal of a horizontal layer of fabric higher than the
rock, the results of unloading square measure typically seen as sheets of rock
that lie parallel to the surface topography.

In
conclusion, weathering refers to the method by that rocks square measure broken

apart with chemicals
altered to become sediment. Physical weathering is once that rock is physically
broken into smaller. This physical ending results from the exposure to the
atmosphere and environment by temperature changes, moisture, biological
activity. It usually occurs in dry desert areas, cold Polar Regions and alpine
zone.

 

 

References

 

1. Christopherson,
Robert W. Geosystems: An Introduction to Physical Geography. Upper

               Saddle River, NJ: Prentice Hall,
1997. Print.

2.
“Weathering.” Philip’s Encyclopedia, Philip’s, 1st edition,
2008. Credo Reference,     

               https://search.credoreference.com/content/entry/philipency/weathering/0.
Accessed 07  

               Dec 2017.

3.
Evans, I. S., 1970. Salt crystallization and rock weathering: A review, Rev.
Geomorphologie 

               Dynam. 19, 153–177.

4. University of
Washington. “Weathering of rocks a poor regulator of global
temperatures.”    

               ScienceDaily. ScienceDaily, 23
May 2017. .

Hyun,
Jung

Geography
5

Professor
Drake

11 Dec 2017

The
Various Types of Mass Movement

 

Mass
movement or mass wasting is movement by direct action of gravity without the
influence of transferring such as water, wind and ice.  It caused by reduced internal friction of the
soil due to earthquakes, heavy rain, and ice of sea. There is a land-slide with
a fast moving speed, and on the other hand, it has a slow and steady speed of
solifluction and soil creep. For a mass movement to take place, the terrain
needs to be up and down or a slope. It is usually caused by heavy rain or
sudden thawing that causes the rock or soil to become saturated with water and
reduce internal friction. In addition, the impact of an earthquake can be a
trigger for mass movement.

There is a solifluction with a mass
movement similar to a creep. This is a type of soil with a lot of water and a
softened soil that flows down faster than the creep even on slopes that are
extremely gentle. It develops well in the area where the aquifer is located,
and the solifluction of the main glacier region is sometimes referred to as
gelification. It refers to a gentle velocity mass movement that occurs at the
surface of a sloping slope. If the rocks such as weathered products on the
gentle slope contain too much water, the fluidity increases and slope movement
is made on an extremely gentle slope, which is a common form of solifluction.
The flow rate is as low as 5 to 50 cm per year, and if it is
liquefied, it becomes a mud-flow with high speed. In the fourth period, a lot
occurred in high mountainous area and main ice glacier area. It is known that
landslides are particularly severe when strong typhoons are blown because of
strong winds shaking the trees and impacting the saturated soil layer with
water. Mudflow is an extreme type of solifluction, which also contains granular
materials such as gravel, but it is overwhelmingly composed of clay and other
fine materials, and the moisture content is about 30% of the total. The rocks
that occur due to the separation of huge rock bodies along joints,
stratification, etc. due to the action of special external factors such as
earthquakes in high mountains are the fastest among the various types of mass
movements and it becomes great disaster. Also, the mudflow contains a lot of
water, so it moves very quickly. On dry area, it is common in the mountains and
volcanoes right after the heavy rain. The movement containing more debris is
called debris flow, and the movement containing more soil is called earth flow.

Another
type of mass movement is Soil creeps, such as those with very slow moving
speeds, can’t be directly observed and can be seen indirectly through phenomena
such as the trees sloping down the slope. When the soil expands, it hears in a
direction perpendicular to the slope. When the soil expands, it sinks in a
direction perpendicular to the horizontal plane. So, the soil moves slightly
down the slope, which slows down the bottom of the soil most rapidly. Also,
Soil creep is a kind of mass movement, which means the movement of soil surface
layer caused by gravity. When the soil layer expands, the rocks are lifted up
in the vertical direction of the slope, and when they shrink, the soil layer
moves downward without descending in the direction of gravity. It appears well
in temperate, temperate and humid climates where the soil layer can be fully hydrated.
It occurs when the expansion and contraction of the soil alternate due to
repetition of freezing and thawing or repeated wetting and drying. The most
important conditions of occurrence are inclines of slopes, which usually occur
by at least 50 degrees, and conditions that affect other activities include
animal activity, earthquakes, and soil particle constituents. The range in
which hunting takes place ranges from surface to 1m below ground. Generally
slower than solifluction or land slide. It caused by freezing and thawing,
drying and wetting, swelling due to heat, plant growth and corrosion. The creep
speed is the fastest on the surface, and the creep speed slows down toward the
surface. Rocks moving in a perpendicular angle direction and moving is called
rock creep.

In
addition, the inclination of the trees is due to the different soil movement
speeds. As the soil becomes saturated with water, it becomes soft, so it can
flow down even in slopes that are very gentle like soil. This phenomenon occurs
well in the permafrost of the tundra climate. This is because in summer, the
water melted in the surface layer is not absorbed into the freezing lower
layer, which saturates the surface soil. Soil flows occur at an extremely
gentle slope of about 2 ° and usually travel up to 10 cm per day or meters per
year. Solifluction occurs well in mountainous areas with clay-rich waste mantle
in wet climates, and can move quickly to destroy houses located below the
slopes in an instant.

Slip movements are largely divided
into rock slides and slumps. The slide is a phenomenon in which a mass of a dry
rock slides and moves on a certain plane without causing a change in the
internal structure. A slope is a rock slider that slides down a group of rocks
of varying sizes on a steep slope, usually along slopes of a stratum surface,
and slides along a curved surface. Initially, it starts with a slump, and when
it goes to the lower tip, it absorbs moisture and moves fluid like advection
and debris flow. The slump occurs mostly in unglacial sedimentary layers.
Erosion in the floodplain is mainly driven by slump.

Finally,
rock avalanche is a fairly rapid fluid mass movement. The huge rock body is
separated along the jointed stratum, and it is flowed in the form of liquidity
movement as it collapses into rockfall after active movement. The air layer
acts as a cushion to reduce frictional forces, allowing for rapid movement. It
also causes a great disaster. Also, rock avalanche refers to a fluid movement
in which a large rock mass is separated along a joint surface or bedding plane
in a high mountain area. Initially, it starts to move like a rock slide due to
active movement, but the rock body collapses to the rockfall as the rock moves,
and the air between the rockfall is heated and compressed to reduce the
friction, thereby making the fastest movement during the fluid movement. The
fundamental reason rock avalanche occurs is because there are many joints in
geology or various kinds of water penetrate into rocks.

The
most common, the foremost liquid, and therefore the quickest sort of flow could
be a mudflow. A combination primarily of the tiniest silt and clay particles
and water, a mudflow has the consistency of fresh mixed concrete. It will
travel down a slope as quick as fifty five miles (88 kilometers) per hour and
have enough force to choose up and carry on rubble the dimensions of boulders,
cars, trees, and houses. Mudflows will travel for nice distances over gently
sloping piece of land. Once they reach natural depression floors, mudflows
detached, depositing a skinny layer of mud mixed with boulders. Mudflow made by
an eruption is termed an avalanche that a combination of volcanic ash, rocks.

In
conclusion, these mass movements indicated from forces of abrasion which are wind,
water, glaciers, waves and gravity. As we learned earlier, gravity is that the
underlying agent of every type of mass movement. While it is not the force of
gravity to drag sediment down associate degree incline, a landslide wouldn’t
occur but any of the opposite four forces also can play a
locality. The down-slope movement of fabric, whether or not or
not its bedrock, regolith, or a combination of those, is often remarked as a
landslide. All of those processes typically grade into each other, therefore
classification of mass movement processes is somewhat troublesome. We are going
to use a standard classification of mass movements, that divides the processes
into two broad classes and additional subdivides these classes’ square measure
slope failures and sediment flows. Slope Failures could be a sharp failure of
the slope leading to transport of trash downhill by slippery, rolling, falling,
or slumping. Sediment flows is material flows downhill mixed with water or air.

References

 

1. Christopherson,
Robert W. Geosystems: An Introduction to Physical Geography. Upper

               Saddle River, NJ: Prentice Hall,
1997. Print.

2. Ribeiro, Marta
foeppel, et al. “An Analysis of Monthly Rainfall and Its Relationship

                to the Occurrence of Mass Movement
and Flooding in Pedra Branca Massif in the City

                of Rio De Janeiro,
Brazil.” Geographical Research, vol. 51, no. 4, Nov. 2013, pp. 398-

                411. EBSCOhost,
doi:10.1111/1745-5871.12015.

3. Sahin, Kemalettin.
“Dynamics of a Mass Movement Triggered by Heavy Rainfall: A Case

               Study from the Black Sea Region
of Northern Turkey.” Norwegian Journal of

               Geography, vol. 58, no. 2, June
2004, pp. 85-89. EBSCOhost, libdb.smc.edu/login?url=

               http://search.ebscohost.com/login.aspx?direct=true=aph=13538467=eh

               ost-live=site.

4. Davies, T R and M J
McSaveney. “Dynamic Simulation of the Motion of Fragmenting Rock

               Avalanches.” Canadian
Geotechnical Journal, vol. 39, no. 4, Aug. 2002, pp. 789-798.

               EBSCOhost,
libdb.smc.edu/login?url=http://search.ebscohost.com/login.aspx?direct=

               true=aph=10585340=ehost-live.

5. Jennings, Terry. Landslides
and Avalanches . North Mankato, MN: Thame-side
Press, 1999.
               Read more: http://www.scienceclarified.com/landforms/Faults-to
Mountains/Landslide-  

              
and-Other-Gravity-Movements.html#ixzz50ixT2Xw2