This document discusses weathering and soil erosion. It defines weathering as the breaking down of rocks and minerals through contact with the atmosphere, water, and organisms. The three main types of weathering are mechanical, organic, and chemical. Soil erosion is the wearing away of topsoil by water and wind forces. There are four main types of soil erosion: splash, sheet, rill, and gully erosion. Causes of soil erosion include land use, climate, soil properties, hydrology, and landforms.

1. Weathering & Soil Erosion
Report by: Veronica Baje

2. Weathering

3. What is
weathering?
Weathering is the
breaking down of rocks,
soil, and minerals as well
as wood and artificial
materials through contact
with the Earth's
atmosphere, water, and
biological organisms.

4. Types of Weathering
1. Mechanical
Weathering
2. Organic Weathering
3. Chemical
Weathering

5. 1. Mechanical Weathering
• Mechanical weathering is also known as physical
weathering. Mechanical weathering is the physical
breakdown of rocks into smaller and smaller pieces.
• Mechanical/physical weathering is also caused by
thermal stress which is the contraction and expansion
effect on the rocks caused by changes in temperature.
Due to uneven expansion and contraction, the rocks
crack apart and disintegrate into smaller pieces.
Examples:
• Frost weathering – happens when water enters the
pores and cracks of rocks, then freezes.
• Salt wedging – can be defined as the process
through which a distinctive saltwater layer creates a
layer of freshwater because of density variations.

6. 2. Organic Weathering
• Organic or biological weathering is the
disintegration of rocks as a result of the
action by living organisms. Trees and
other plants can wear away rocks since as
they penetrate into the soil and as their
roots get bigger, they exert pressure on
rocks and makes the cracks wider and
deeper.

7. 3. Chemical Weathering
• Chemical weathering happens when rocks are worn
away by chemical changes. The natural chemical
reactions within the rocks change the composition of
the rocks over time. Because the chemical processes
are gradual and ongoing, the mineralogy of rocks
changes over time thus making them wear away,
dissolve, and disintegrate.

8. Soil Erosion

9. What is Soil
Erosion?
• Soil erosion is a
naturally occurring
process that affects all
landforms. In
agriculture, soil erosion
refers to the wearing
away of a field's topsoil
by the natural physical
forces of water and wind
or through forces
associated with farming
activities such as tillage.

10. Types of Soil Erosion
1. Splash Erosion
2. Sheet Erosion
3. Rill Erosion
4. Gully Erosion

11. 1. Splash Erosion
• Splash erosion is the first stage of the
erosion process. It occurs when raindrops
hit bare soil. The explosive impact breaks
up soil aggregates so that individual soil
particles are 'splashed' onto the soil
surface.

12. 2. Sheet Erosion
• Sheet erosion is the uniform removal of soil
in thin layers by the forces of raindrops and
overland flow. It can be a very effective
erosive process because it can cover large
areas of sloping land and go unnoticed for
quite some time.

13. 3. Rill Erosion
• Rill erosion is the removal of soil
by concentrated water running
through little streamlets, or
headcuts. Detachment in a rill
occurs if the sediment in the flow
is below the amount the load can
transport and if the flow exceeds
the soil's resistance to
detachment.

14. 4. Gully Erosion
• Gully erosion is the removal of soil along
drainage lines by surface water runoff. Once
started, gullies will continue to move by
headward erosion or by slumping of the side
walls unless steps are taken to stabilize the
disturbance.

15. Causes of Soil Erosion
1. Land Use – includes deforestation, grazing, arable land use,
faulty farming systems, high crop intensity, housing construction,
mining etc.
2. Climate – includes water balance, evapotranspiration,
temperature and relative humidity.
3. Soil – factors are texture, structure, water retention and
transmission properties.
4. Hydrology – Infiltration, surface detention, overland flow velocity,
and subsurface water flow are important soil erosion components
of the hydrological cycle.
5. Landforms – Slope gradient, slope length and shape of slope are
the important variables of landform that affect erosion processes
for all types of soil erosion, e.g., splash, sheet, rill, and gully
erosion.

16. Source:
https://www.eartheclipse.com/geology/different-types-of-weathering.html
https://opentextbc.ca/geology/chapter/5-1-mechanical-weathering/
https://en.m.wikipedia.org/wiki/Soil_erosion
milford.nserl.purdue.edu/weppdocs/overview/sheet.html