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Rock Cycle
• Sedimentary Rocks:
(Cementation and
compaction)
• Formed when particles of
rocks, sand and pebbles
are pressed together by
water, pressure and
natural cementing agents.
Often they are layered
rocks, and break rather
easily.
There are three types of
sedimentary rocks:
Clastic: Separate fragments of
sediment become cemented and
compacted together into solid rock.
EX. Conglomerate,sandstone,
shale.
Chemical: Rock forms from
minerals that were once dissolved
in water.
EX. Halite, gypsum, geodes
Organic: Rock forms from the
remains of living organisms.
EX. Limestone, coal
Metamorphic Rocks:
( Heat, contact and/or pressure)
Metamorphic means “changed.”
Heat, pressure and strong
chemicals turn rocks into
metamorphic rocks. This happens
inside the earth. Often times
earthquakes cause rocks to
change. They are hard, dense
and often have crystals.
There are two ways by which one
can identify metamorphic rocks:
• Foliated: Extreme
pressure squeezes the visible
crystals into parallel lines,
forming bands or layers.
• Unfoliated: The pressure
squeezes the rock, but there
are no visible crystal layers.
Some common examples of
metamorphic rock are
• Marble
• Slate (from Shale)
(from limestone)
• Gneiss
• Quartzite
( from sandstone)
( from Granite)
Igneous Rock
(Heat, melting and
cooling)
Igneous means “formed by
fire.” Heat within the earth
(Hot magma) forces
minerals to become rocks.
All volcanic rock is igneous.
There are two types of igneous
rocks:
• Intrusive: Igneous rock
formed inside the earth.
ex. Granite
Extrusive: Igneous rock
formed outside the earth. This
rock is also referred to as
“Volcanic Lava.”
ex. Obsidian, Pumice, Basalt
Can all 3 types of rocks become
the other type of rock through
some kind of process?