Transcript 3 Major Rock Groups

There are 3 Major (Geologic)
Rock Groups
Not the Rolling Stones, Kiss, or Van Halen
1. Igneous Rock
2. Sedimentary Rock
3. Metamorphic Rock
Rocks are made of minerals
and make up Earth’s solid crust
-Forms when a hot, molten liquid, below ground,
called magma, crystallizes (cools and solidifies).
Magma forms 3 ways:
1.
Rock is heated
2.
Pressure released
3.
Change composition
Basalt lava (glowing rock) oozes over basalt lava flow
Holt Online Visual: Comparing Int. & Ext Igneous Rocks
A. Igneous Rock
a.
Intrusive Igneous Rock
-Forms or crystallizes inside Earth
-slow cooling
b. Extrusive Igneous Rock
-Forms on surface (exterior) of Earth
-Fast cooling
Fine-grained-made
Ex:
of interlocking crystals.
basalt - the most common extrusive igneous rock
BASALT
More Igneous Rocks…
Course
grained
texture=
Granite,
the most
common
intrusive.
Sedimentary Rock
*There are 3 types of sedimentary rocks.
*Often times, sand, mud, pebbles, or shells settle out
in wind and water, get compacted and/or
cemented together, and harden into rock.
Here, rocks
hardened in
layers called
strata from a
process known
as…
stratification.
3 Types of Sedimentary Rock
1. Clastic -forms when rock or mineral fragments are
cemented together.
2. Chemical forms when minerals crystallize out of
solution, such as sea water, to become rock.
3. Organic forms from the remains of once-living plants
and animals.
Ex: Limestone
Coal
Chalk
Metamorphic Rock
-Rocks that have undergone a change in texture, structure,
or composition.
-Changes in heat and pressure cause rocks to change from
one form to another.
Rocks are made, destroyed, and
created again, in a process called
the Rock Cycle