Transcript Sedimentary Rocks

Sedimentary
Rocks
Sediments (notes)
• Bits of rock and soil which have
been broken down from larger
rocks.
• Sediments are “glued” together to
form sedimentary rocks.
Sediments (notes)
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Boulders
Cobbles
Pebbles
Sand
Silt
Clay
Largest
Smallest
Types (notes)
• Clastic – Inorganic pieces
cemented together
• Bioclastic – Organic pieces (shells,
plant remains)
cemented together.
• Crystalline – Formed from
evaporites
How to make a clastic sedimentary
rock. (notes)
Step 1: Layers of sediment are
deposited by air, water, or ice.
Step 2: Over millions of years, as the
layers are buried under more
sediment, the weight pressing
down on the layers squeezes
all water out.
Step 3: As the water disappears, the
particles are cemented together
by salt.
How to make a clastic sedimentary
rock (notes)
This process is known
as
Compaction and
Cementation
How to make a crystalline
sedimentary rock (notes)
• Water carries a lot of dissolved particles
(i.e. salt)
• As the water evaporates it leaves behind
the dissolved particles.
• These particles become cemented
together to form a solid rock (i.e. rock salt)
What they look like (notes)
Sedimentary rocks look
similar to the sediments
that made them.
Sandstone (notes)
• Formed from
layers of sand
from deserts,
sand dunes and
beaches
Limestone (notes)
• Formed from the
crushed shells of
animals living in
warm shallow
seas.
• Mostly calcite
• Bubbles with acid
Shale (notes)
• Formed from clay
which has settled
in calm lakes and
estuaries, and
oceans.
Conglomerates (notes)
• Contains pebbles
set in a cement of
finer particles.
• Formed from
riverbeds and
beaches