6. • mechanical weathering
• the breakdown of rocks
without a change in its
composition.
• Breakdown would mean that the rock is
fractured, cracked or fragmented into
smaller pieces.
Physical Weathering
11. • decomposition of rocks due
to chemical reactions
occurring between the
minerals in rocks and the
environment.
• transforms rocks and minerals exposed to
water and gases in the atmosphere into new
chemical compounds thus, forming different
rocks and minerals.
Chemical Weathering
14. a key factor in the creation
of caves and caverns. It
can also hollow out caves
and damage cliffs.
Chemical
weathering
15. 1.THERMAL AND PRESSURE CHANGE
• Rocks crumble and break into fragments
because they are subjected to alternating
hot and cold temperatures many times.
• When a rock gets hot, it expands an
increase in volume), while at night, the rock
gets cold causing contraction (a decrease
in volume).
Processes that can Cause
Physical Weathering
16. • Temperature weaken the rock and in the process, mineral grains
are loosened from the rocks and eventually the rocks break down
into pieces. Best examples are the stone in the arid desert that
slowly turn to sand.
• The rates of expansion and contraction of the outer and inner
parts of the rock differ. The outer part expands and contracts
much more than the inner part because it is directly exposed to
the heat of the sun.
17.
18.
19. 2. WIND AND WAVES
• Wind and waves can all cause physical
weathering. Tiny grains of sand are
picked up and carried off by the wind,
which are then blasted on the surface of
rocks, smoothening them.
• On the seashore, the action of waves
chips away and cracks the rocks.
Processes that can Cause
Physical Weathering
20.
21.
22. 3. FREEZE AND THAW
• You know that if you put a glass in the
freezer it will soon break. This is because
water expands when it freezes. Similarly,
when water collects in the rock pores
and slits, it expands when it freezes.
Processes that can Cause
Physical Weathering
26. 4. ORGANIC ACIVITY
• Animals and plants also take a heavy
toll on rocks and cause them to wear
away.
• For example, there are animals that
dig holes on the ground and exposed
rocks.
Processes that can Cause
Physical Weathering
27.
28. 1.HYDRATION/ HYDROLYSIS
•Process where molecules
of some substance in rocks
chemically combine with
water molecules
Processes that can Cause
Chemical weathering
29.
30. 2. CARBONATION
• Process where Carbon Dioxide may
bond with other substances.
• A mixture of water and carbon
dioxide is called carbonic acid.
• Two examples of carbonation weathering are The
Limestone Pavement and The Stalactites.
Processes that can Cause
Chemical weathering
31. This land form is made entirely of limestone and formed
by rainwater carbonation and the freezing and thawing
process.
32. This land form is also made of limestone. It was created by
large amount of calcium being dissolved in them.
33. 3. OXIDATION
• Iron, aluminum, copper, and sodium
are examples of minerals that readily
react with oxygen which then form
mineral oxides.
• In nature, physical and chemical weathering typically
occur together, affecting the rocks. When the latter is
destroyed, valuable products are created.
Processes that can Cause
Chemical Weathering
35. • Involves the movement of the
weathered rock (snow, soil,
sand and pebbles) from their
site of weathering by the
agents of erosion such as wind,
moving water, ice and gravity.
Erosion
36. • Weathering dos not always occur
before erosion. Erosion always follows
after the weathering.
• Transport makes erosion complete. It
complete the movement of the
eroded materials and sediments.
Weathering can continue during
transport.
Erosion
37. Transport by the water
• Rainwater is the most important force or agent of
erosion. When there is heavy rain, rock pieces
are carried downstream to a suited depositional
environment with the action of gravity.
• Gravity is the driving force and it gives water the
energy to erode and carry away rock materials.
• Physical weathering dominates at higher
elevation while Chemical weathering takes on a
more active role at lower elevation.
Transport by the
water
38. • Water can carry almost any size of rocks. The
greater the volume of water and the steeper the
slope, the bigger and more rocks can be
transported.
• Serious problems in the Philippines are soil erosion
and mudslide
• Rock materials are loosened by heavy rains and
strong winds and they can come speeding down
slopes, sweeping everything in its path.
Transport by the
water
39.
40. • Wind continuously blows away loose particles of
rocks and soil from place to place.
• This is common in dry areas such as deserts.
• Wind transport can result in stunning landscapes
as sand is blown away and creates sand dunes.
• Wind can create sandstorms that contain dust
particles and deposit them in wide areas.
Transport by the
wind
42. • slope movement
• bulk movements of soil, sand, and rock
debris downslopes in response to the
force of gravity or the rapid or gradual
sinking of the Earth’s ground surface in
a vertical direction.
• The term “mass wasting” was limited only to the variety of
processes by which large masses of crustal materials are
moved by the action of gravity form one place to another.
Mass movement
(mass wasting)
43. • Recently, the term “mass wasting”
has been substituted to include mass
wasting processes and the sinking of
the Earth’s ground.
• Mass wasting is a type of erosion that
is capable of making big chances to
a mountain.
Mass movement
(mass wasting)
44. • Sinking mass movement that occurs
in a relatively rapid fashion is known
as subsidence; and a gradual
movement is called settlement.
• Subsidence involves the roof collapse or breakdown of a
subsurface cavity forming a cave.
• There is also subsidence in the form of sinkholes caused by
underground drainage.
Mass movement
(mass wasting)
53. REFERENCE:
• Moncada, M. et. al (2016). Earth and Life Science for Senior High School.
Disclaimer:
The pictures used in this slideshow presentation were obtained from various internet
websites and will be only used for educational purposes only.
