Mechanical weathering is the process through which big rocks are damaged into progressively smaller pieces. Sometimes referred to as physical weathering, the process normally happens near the earth surface. Can you believe that the small sand seed you view at the beach were once component of substantial rocks?

It entails mechanical processes that disintegrate a rock, prefer tree roots cultivation in crack in a rock and also eventually breaking it up. Mechanical weathering doesn’t readjust the chemistry nature of the rocks.

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In this article, we look at how mechanical weathering works, that types, and also some examples. Let’s dive in.

Process of mechanical Weathering

The main procedure in mechanically weathering is abrasion, a physical process by i beg your pardon rocks and clasts are reduced in size. Abrasion through ice, water, and wind procedures loaded through sediments deserve to have immense cutting power. The world’s greatest gorges, valleys, and also ravines are greatly a result of abrasion.

In glacial regions, substantial masses of relocating ice installed with soil and also rock particles grind down rocks in your path, moving away big volumes the material. Tree roots periodically penetrate crack in rocks and also wedge lock apart, leading to disintegration.

Temperature fluctuations from daytime to nighttime may reason a rock to expand and also contract. This weakens the rock, resulting in it to fracture and eventually disintegrate. To have actually a deeper understanding of these processes, let’s discover the different varieties of mechanically weathering.

Types of mechanically Weathering

There room five major types of mechanical weathering: thermal expansion, frost weathering, exfoliation, abrasion, and also salt decision growth. Chandelier we have a comprehensive look in ~ them?

1. Thermal Expansion

Minerals generally expand and contract as result of temperature fluctuations. This process is called thermal expansion. Rocks space composed of assorted minerals, i m sorry expand and also contract at different rates as soon as subjected to fast temperature changes.


The fluctuations cause stress and little cracks in the rocks, gradually breaking under the rock. Grus is a standard example of the thermal development process. It is the coarse-grained and loose fragments deposit that stays behind ~ weathering. So, Grus is the direct result of the physics weakening and also disintegration the rock over time.

2. Abrasion and Impact

Rocks deserve to be damaged up by friction and consistent impact with various other rock pieces throughout transportation. Namely, a absent fragment carried along in the raging currents of a river repeatedly rubs itself against other fragments and the flow bed.

In the end, the fragment disintegrates into tiny pieces. This type of mechanically weathering also occurs throughout wind and glacial ice transportation.

3. Exfoliation or press Release

When the overlying boulders room stripped by abrasion and other erosion mechanisms, they reason the underlying rocks parallel to the surface ar to crack, fracture, and also expand. Consequently, the basic rocks release the pressure in them.

As time passes, sheets of rock peel away from the stripped rocks and also disintegrate right into smaller pieces along the fractures. The process is known as exfoliation. That occurs when rocks parallel come the land surface break up as a result of the push release throughout abrasion, absent uplifts, or retreat of one overlying glacier.

4. Frost Weathering

Frost weathering is additionally known as ice wedging. That is the cumulative term for miscellaneous processes that involve ice. The procedures include:

Freeze-thawFrost WedgingFrost shattering

Frost weathering occurs mostly in mountain areas where the temperatures room close come the freezing allude of water. Assorted frost-prone soils freeze and expand together water migrates through capillary activity to construct ice lenses close to the freeze point.

This process also takes location within spicy spaces the rocks. The accumulations of ice cream increasingly thrive as they attract liquid water from the surrounding pores. The consistent growth the ice crystal weakens the rocks, ultimately breaking castle up.


Frost weathering is common in environments where over there is many of moisture, and also temperatures regularly fluctuate below and over freezing point. Alpine and also periglacial areas are specifically prone come this type of weathering. And chalk is among the rocks that are susceptible to frost weathering.

It has countless pore spaces for ice crystals growth. The formation of tors in Dartmoor is a common example the frost action on chalk. Once the water the has discovered its method into the joints freezes, the ice produced strains the walls of the joints. This outcomes in the deepening and widening of the joints.

Water could flow more into the rock as soon as the ice thaws. Recurring freeze-thaw cycles makes the rock weak end time, eventually breaking that up follow me the joints right into angular fragments. The fragments accumulate in ~ the foot of the steep to type a scree steep or talus slope. The fragments take different shapes relying on the framework of the rock.

5. Salt-crystal Growth

Salt-crystal development is additionally known together haloclasty or salt weathering. It is the process by i m sorry saline solutions get in the cracks in a rock and also evaporates, leave behind salt crystals.

When eco-friendly temperatures rise, the built up crystals room heated up. Together a result, lock expand and also release push on the rock, resulting in it to rest up.

Salt-crystal growth may likewise occur as soon as rocks favor limestone kind salt services such as sodium sulfate or sodium carbonate. This solutions kind crystals once the water molecule in castle evaporate. The salt can expand over 3 times. This procedure is usual in dry and also high-temperature regions.

6. Plant and also Animal Activities

Plants roots are very powerful and can thrive into the crack of currently rocks. Together the roots continue to flourish in the cracks, lock act as a wedge, exerting push on the rock until it cracks further and also eventually disintegrates into smaller fragments.


Animals such together rabbits, moles, and groundhogs, on the other hand, burrow holes in the ground, which can expose basic rocks to the aspects of weathering. Water and also other agents of mechanical weathering discover their method into the formerly covered rocks, thanks to the holes. It then starts and speeds up the mechanically weathering process.

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Examples of mechanically Weathering

Real human being examples of mechanical weathering are simple to spot. They incorporate the following:

The skinny Talus steep near shed river in Virginia is a good example of Frost WeatheringBornhardts are products of exfoliation. They are tall, domed, isolated rocks normally found in tropical areas. Sugarloaf mountain in Rio de Janeiro, Brazil, is probably the finest example the a bornhardt.Underlying tree roots piece out entirety slabs of a sidewalkOld gravestones are typically hard to read since weathering has washed far the lettersIce wedges room a leading reason of potholes in roads and streets. When ice forms in the crack of a road, the water expands, pushing against the surrounding rock. This renders the crack wider, eventually disintegrating the rock.Forest and range fires can result in weathering in rocks that are located along the floor surface.Water flowing in a stream right into a absent will ultimately bore a hole in the rock.Thermal anxiety weathering typically occurs in desert climates, which room hot during the day and also cold in ~ night. The everyday heating and also cooling processes put stress and anxiety onto rocks in the external layer, making them start peeling turn off in thin sheets.Reference Links:https://www.nationalgeographic.org/encyclopedia/weathering/https://www.thoughtco.com/mechanical-weathering-1440856
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