Download Sorting Igneous Rocks

Sorting Igneous Rocks
3 Types of Rocks
• Igneous = FIRE
• Sedimentary
• Metamorphic
Goals:
• Describe how igneous rocks form.
• Identify the physical characteristics and
compare/contrast:
– Igneous Rocks vs. Sedimentary Rocks
– Extrusive vs. Intrusive Igneous Rocks
• Make inferences about the geological
processes that formed rocks through
observing their physical characteristics.
Some Igneous Rocks
Granite
Diorite
Pegmatite
Gabbro
Obsidian
Pumice
Igneous Rock = made in fire
1.
2.
Magma rises
Lava erupts
2 kinds of Igneous Rock
1. Intrusive = inside Earth
2. Extrusive = outside Earth
Lava erupts
Magma rises
Intrusive Igneous rock forms
•
when magma rises into the cracks in the Earth’s crust and cools and
hardens very slowly.
1.
Intrusive Igneous rock
•
The magma cools and hardens very slowly because it stays warm and
insulated inside the crust.
1.
Granite
Intrusive Igneous Rocks
Granite
Medium size grains
• Magma cools slowly beneath
the Earth’s surface.
• The longer it takes the
magma to cool, the larger the
grains can grow out of the
magma before it hardens into
rock.
Pegmatite
Large size grains
• Pegmatite is very coarse
grained (big grains) so the
magma cooled and hardened
very slowly.
The grains in rocks are made of minerals.
Minerals are natural forming materials found on and in the Earth.
Each mineral has a different color.
Granite
Different color Minerals in Granite
Mineral called Quartz – slowly cooled and hardened into crystals
Different Minerals
Just as different foods can make up a cookie, different minerals
can make up a rock.
Some Intrusive Igneous Rocks
Granite
Peridotite
Granite
Peridotite
Gabbro
Gabbro
Some Intrusive Igneous Rocks
Andesite
Diorite
2 kinds of Igneous Rock
1. Intrusive = inside Earth
2. Extrusive = outside Earth
Lava erupts
Magma rises
Extrusive Igneous rock forms when:
• lava erupts out of a volcano and then cools and hardens quickly into rock.
Extrusive Igneous rock
• It cools and hardens quickly into rock because it is exposed to air or
water.
Basalt
Extrusive Igneous Rocks
Basalt
Rhyolite
• Lava cools quickly at
the Earth’s surface
• Lava that cools very
quickly produces
very fine grains or
really small grains.
• Can you see any
grains?
• You can’t really see mineral grains in Extrusive
Igneous rocks because they cool and harden too
fast and the minerals don’t have time to form
into crystals or big grains.
Some Extrusive Igneous Rocks
Basalt
Rhyolite
Obsidian
Obsidian
Pumice
Scoria
How the Earth was Made
• Yosemite: Minute 13. How cooling effects rock
strength/crystal size.
Activity 2:
Sorting Igneous and Extrusive Rocks
Lab 1
• Your group will examine a case of rock
samples from the Grand Canyon region and
rock samples from the Cascade Mountain
region.
• Sort the rocks into sedimentary or igneous
rocks based on their physical characteristics.
Complete your group lab response.
Lab 2
• After reviewing slides presenting extrusive and
intrusive igneous rock, sort your rocks into
these groups based on their physical
characteristics.
Lab 3
• Your group will receive samples of igneous
rock. Infer which geological processes may
have formed this rock. Your group will tell the
“story of the rock” when you present it to the
classroom.