Dr. Dave Hardin (Luke’s Dad)
Associate Professor of Geography
Longwood University
ROCK CYCLE
Earth’s surface
Intrusive
Igneous
D. Hardin
INTRUSIVE IGNEOUS ROCK
Blue Pearl Granite - Norway
Petersburg Granite - Virginia
Mt. Rushmore, South Dakota
D. Hardin
INTRUSIVE IGNEOUS ROCK
Devil’s Tower,
Wyoming
Sheepeater Cliff,
Yellowstone NP,
Wyoming
Giant’s Causeway,
N. Ireland
D. Hardin
ROCK CYCLE
Extrusive
Igneous
Rise of
magma
Earth’s surface
Intrusive
Igneous
Rise of
magma
D. Hardin
EXTRUSIVE IGNEOUS ROCK
Volcanic ash
Obsidian
Obsidian tools
Ash (magnified)
Lava (pahoehoe)
Pumice
D. Hardin
EXTRUSIVE IGNEOUS ROCK
Kilauea,
Hawaii
Mt. St. Helens,
Washington
Lava Butte,
Oregon
Inferno Cone, Idaho
D. Hardin
ROCK CYCLE
Weathering:
Disintegrate
Decompose
Dissolve
Extrusive
Igneous
Rise of
magma
Uplift & uncovering
Earth’s surface
Intrusive
Igneous
Rise of
magma
D. Hardin
WEATHERING
DISINTEGRATE
frost wedging
sandblasting
DECOMPOSE
Coolest job in America!
biological
weathering
DISSOLVE
ROCK CYCLE
Weathering:
Disintegrate
Decompose
Dissolve
Extrusive
Igneous
Rise of
magma
Intrusive
Igneous
Uplift & uncovering
Erosion
&
deposition
Earth’s surface
Burial &
lithification
Sedimentary
Rise of
magma
D. Hardin
SEDIMENTARY ROCK
Grand Canyon, Arizona
Dinosaur trackway
D. Hardin
SEDIMENTARY ROCK
Environment
Sediment
Desert
Floodplain
Sand
Mud
Swamp
Plants
Sandstone
Shale
Animals
Warm, shallow sea
Rock
Limestone
Coal
D. Hardin
ROCK CYCLE
Weathering:
Disintegrate
Decompose
Dissolve
Extrusive
Igneous
Rise of
magma
Uplift & uncovering
Erosion
&
deposition
Earth’s surface
Burial &
lithification
Intrusive
Igneous
Sedimentary
Rise of
magma
Metamorphic
D. Hardin
METAMORPHIC ROCK
Sedimentary parent
Sandstone
Quartzite
Quartz
Michelangelo’s
“David”
Shale
Limestone
Slate
Marble
?
Coal
Carrara, Italy
D. Hardin
Coal comes
from the carbon
in decayed
plant matter.
…and when buried under
relatively shallow
sedimentary layers, is
metamorphosed into
lignite…
It begins as
deposits of
peat…
…then
bituminous
coal…
Carbon that is formed
at shallow depths in
the earth’s crust or
…and finally,
coal that is
anthracite coal.
metamorphosed
as a result of tectonic
processes, becomes
graphite.
Coal is also relatively young geologically. The plant matter that formed Virginia’s coal
was deposited in the Pennsylvanian Period about 300 million years ago. Western coals
were deposited as recently as the Cretaceous Period about 70 million years ago.
On the other hand, when carbon formed deep in the earth as far back
as 3 billion years ago, a very hard and rare mineral was created…
D. Hardin
ROCK CYCLE
Weathering:
Disintegrate
Decompose
Dissolve
Extrusive
Igneous
Rise of
magma
Uplift & uncovering
Erosion
&
deposition
Earth’s surface
Burial &
lithification
Intrusive
Igneous
Sedimentary
Rise of
magma
Metamorphic
D. Hardin
CLASSROOM EXAMPLES
Intrusive Igneous
COOLED SLOWLY
UNDER THE
SURFACE!
CRYSTALS!
HARD!
STRONG!
MADE TO LAST!
(all granite)
D. Hardin
CLASSROOM EXAMPLES
Extrusive Igneous
COOLED QUICKLY
ABOVE THE
SURFACE!
volcanic
ash
VOLCANIC
GLASS!
NO
CRYSTALS!
obsidian
lava
pumice
D. Hardin
CLASSROOM EXAMPLES
Sedimentary
fossiliferous
limestone
MADE OF BURIED
SEDIMENTS!
sandstone
FOSSILS!
shale
coal
(bituminous)
LAYERED!
D. Hardin
CLASSROOM EXAMPLES
Metamorphic
CHANGED INSIDE
THE EARTH!
STRONGER THAN THE
PARENT ROCK!
schist
CAN HAVE SOME
QUALITIES OF
THE PARENT
ROCK!
quartzite
marble
D. Hardin
ROCK CYCLE
Weathering:
Disintegrate
Decompose
Dissolve
Extrusive
Igneous
Rise of
magma
Uplift & uncovering
Erosion
&
deposition
Earth’s surface
Burial &
lithification
Intrusive
Igneous
Sedimentary
Rise of
magma
Metamorphic
D. Hardin