Exogenic processes, occurring on or near Earth's surface, are influenced by gravity, water, wind, and organisms, and can drastically alter landscapes and ecosystems. Weathering, both mechanical and chemical, contributes to soil formation, while erosion and deposition involve the movement and settling of weathered materials. These geologic processes, which include mass wasting and sediment accumulation, continuously reshape ocean basins and continental areas.

1. Geologic
Processes on
Earth

2. Exogenic
Processes

3. The exogenous processes occur on or near
the surface of Earth. They are usually
influenced or driven by gravity, water, wind,
and organisms. These could be destructive
occurrences that leave significant changes on
the landscape and even in the ecosystem of
an area. In extreme cases, exogenous
processes can wipe out majority of the
organisms inhabiting that area.

4. Mechanical weathering or physical
weathering is the breakdown of rocks
into pieces without any change in its
composition. In this process, the size
and shape of rocks changes and this
occurs because of the following factors
shown in the table below.

5. Factors Description
Pressure
Due to tectonic forces, granite may rise to
form mountain range. After the granite
ascends and cools, the overlying rocks and
sediments may erode. At the point when the
pressure diminishes, the rock expands, cools,
and became brittle and fractured.
Temperature
Rocks expand and are fractured when
expose to high temperature. However, if the
temperature drops to 0°C (freezing point of
water), it also expands and causes fracture.

6. Factors Description
Frost
Wedging
Generally, rocks have fracture in its surface
and when water accumulates in the crack and
at that point freezes, the ice expands and
breaks the rock apart.
Abrasion
The breakdown of rocks is caused by impact
and friction. This primarily occurs during
collision of rocks, sand, and silt due to current
or waves along a stream or seashore causing
sharp edges and corners to wear off and
become rounded.

7. Factors Description
Organic
Activity
The roots grow causing penetration into the
crack, expand, and in the long run, break the
rock.
Human
Activities
Activities such as digging, quarrying,
denuding forests and cultivating land
contribute to physical weathering.
Burrowing
Animals
Animals like rats, rabbits and squirrels
excavate into the ground to create a space for
habitation.

8. In chemical weathering, there are changes in the composition of rocks due to the chemical reactions presented below.
Chemical
Reactions
Description
Dissolution It occurs in specific minerals which are dissolved in
water. Examples of these minerals are Halite (NaCl)
and Calcite (CaCO 3 ). The formation of stalactites
and stalagmites in caves are brought about by this
chemical reaction.
Hydrolysis Rock-forming minerals like amphibole, pyroxene,
and feldspar react with water and form different
kinds of clay minerals.
Oxidation It is the response of oxygen with minerals. If the iron
oxidizes, the mineral in rocks decomposes. Rusting is
an example of this chemical reaction.

9. Weathering is an important
process in the formation of soil.
Soil is a mixture of grains,
organic matter, H2O, and gas.

10. Erosion
is the separation and removal of
weathered rocks due to different agents
like water, wind, and glacier that causes
transportation of the material to where
they are deposited. Plants, animals, and
humans play an important role in the
erosional process.

11. The movement of
sediments downslope under the
influence of gravity is called mass
wasting.
The examples of this are
fall, slide, avalanche, and flow.

12. Deposition
is the process in which the
weathered materials carried out
by erosion settle down in a
particular location.

13. It is the accumulation of materials
such as soil, rock fragments, and soil
particles settling on the ground. This
usually occurs in streams and sea
erosion. Over time, the sediment load
becomes thick and forms a new layer
of ground.

14. In some small inland waters, this sediment
layer will eventually dry up the water and
become part of the soil. In oceans, the
sediment layer can form the ocean basin.
Because geologic processes are constant,
ocean basins change in size and depth. The
change depends on the rate of erosion in
their surrounding continental masses or by
ocean ridges.