Download Rock Cycle PPT

An Introduction to
the Rock Cycle
Rocks
 There are three (3) main
types of rocks:
 Rocks can be igneous,
sedimentary, or
metamorphic.
Igneous Rocks
o
Igneous rocks are formed when molten rock
(magma) cools and solidifies, with or without
crystallization, either below the surface as
intrusive rocks or on the surface as extrusive
(volcanic) rocks.
Granite is an igneous rock
Sedimentary Rock
Sedimentary rock is formed in three main ways:
1.
2.
3.
by the deposition of the
weathered remains of
other rocks (known as
clastic sedimentary
rocks)
by the deposition of the
results of biogenic
activity
by precipitation from
solution
Limestone and shale are both
types of sedimentary rock
Metamorphic Rock
Slate is a type of
metamorphic rock
 Metamorphic rock is the result of the
transformation of a pre-existing rock type.
 Metamorphic means "change in form“.
 Heat and Pressure physically and chemically
The Rock Cycle
Weathering
• Weathering is the process of decomposition
and/or disintegration of rocks, soils and their
minerals through natural, chemical, and
biological processes.
Erosion
• Erosion is the displacement
of solids (soil, mud, rock,
and other particles) because
of wind, water, ice, gravity,
or living organisms.
• Deforestation, overgrazing,
and road or trail building
are human activities that can
lead to erosion.
physical weathering
Frost heaving
•
Frost heave is the result of pressure created
from a combination of freezing
temperatures and soil defrosting. The
fluctuating freezing and thawing conditions
heave, or lift, the soil, which is often
characterized by deep cracking of the soil.
Plants may be uprooted from the ground as
well.
Frost wedging
•
•
•
•
Frost wedging is caused by the repeated freeze-thaw
cycle of water in extreme climates.
Most rocks have small cracks in them, called joints.
When it rains, rainwater seeps into these joints. As
the day cools and temperatures at night drop below
freezing, the water inside the joints freezes.
As water freezes into ice, it expands.
The expanding ice places pressure on the joints in
the rock. Finally, when the pressure is too much,
the joint expands. In some cases, the rock will split,
though this usually happens after repeated freeze
and thaws. As new water is added during the
warmer days, more ice is created at night, wedging
the joints apart further.
physical weathering
Plant roots
Friction and impact
• The roots of large plants can
penetrate the rocky soil and
break it apart.
• Constant exposure to friction
and impact can change the
formation of the rocks and
cause them to break off.
physical weathering
Animals
Temperature changes
• Animals that burrow into
rocks can cause weathering.
• The changing temperatures
can alter landscapes by
causing the soil to freeze or
burn.