Download Sedimentary Rocks

Sedimentary Rocks
What are Sedimentary Rocks?
• Sediment- fragments of rock that
have been broken down as a result
of weathering and erosion by wind,
water, and ice.
• Sedimentary Rock- formed by the
accumulation and
cementing/compacting of
sediments.
Types of Sedimentary Rocks
• There are 2 types of sedimentary
rocks:
• Clastic sedimentary Rocks
• Chemical Sedimentary Rocks
Clastic Sedimentary Rocks
• Clastic Rocks- Form from
compacted sediments.
• They are inorganic.
• Classified by the size of the sediment.
• Shale- smallest grains
• Siltstone
• Sandstone
• Breccia
• Conglomerate- largest grains
Conglomerate
Shale
Chemical Sedimentary Rocks
• Chemical Rocks- Made from the
precipitation of water.
• This is broken down into 2
categories:
• Crystalline
• Organic
Crystalline Sedimentary Rocks
• Crystalline Rocks- Form from a chemical process.
• Also known as evaporites and precipitates.
• Evaporite- sedimentary rocks formed by the evaporation
of water.
Dolostone
• Precipitate- forms when water is so full of a dissolved
mineral that the mineral no longer dissolves and
crystallizes in the water.
• Examples:
• Rocks salt
• Rock Gypsum
• Dolostone
Rock Salt
Organic Sedimentary Rocks
• Also known as bioclastic or biochemical
•
•
•
•
sedimentary rocks.
Organic Rocks- Made from compacted organic
matter (things that were once living)
The only rock that contains fossils or evidence of
life.
Depending on the grain size, an organic sedimentary
Biochemical Limestone
rock can be chemical or clastic.
Examples:
• Coal
Fossil
• Biochemical Limestone
• Fossils
Coal
Sedimentary Rock Textures
• How does the rock feel?
• Clastic Sedimentary Rocks
• You can see the grains with your eyes or with
a magnifying glass.
• If you rub the rock, dust particles are left on
your hand.
• Chemical Sedimentary Rocks
• If it looks smooth like plastic or if you can
see a crystal structure.
Sedimentary Rock Composition
• What is the rock made of ?
• Organic
• If the rock contains a fossil, shells, or
any other signs of former life, the
rock is bioclastic/organic.
• Inorganic
• If the rock does not have any signs of
life, then it only contains minerals.
Classifying Sedimentary Rocks
• Identify the rock’s:
• Texture
• Composition
• Texture + Composition= rock name
• Once the rock is identified, you can
use it to learn about a region’s past.
Why Study Sedimentary Rocks?
• Sedimentary rocks are a great way to
examine an area’s past.
• The rock material and fossils present
can help you make conclusions about
how the environment used to be in a
given area.
• Example:
• Based on evidence from sedimentary
rocks, scientists were able to discover
that Death Valley used to be a lake.
Watch This and Fill Out Your Graphic
Organizer
https://www.youtube.com/watch?v=Etu9BWbuDlY