Transcript sedimentary rocks

SEDIMENTARY ROCKS
There are 2 ways sedimentary rocks are formed
1.
Clastic are made from sediments glued
together
2.
Non-clastic: not glued together---include
chemical & biochemical/organic
SEDIMENTARY ROCKS WILL CONTAIN FOSSILS.
SEDIMENTARY ROCKS FORM IN LAYERS
CALLED STRATA
Oldest rocks are on the
bottom….youngest on top
This is a good example of Stratification
THE 2 CLASSES OF SEDIMENTARY ROCKS
1. CLASTIC Sedimentary Rocks are made from
sediments that come from pre-existing rocks that have
been weathered (breaking down into smaller pieces)
and eroded (transported away) then glued together.
The 2 types of weathering include physical (only size
changes) and chemical (a new substance is formed).
Sediments range in size from tiny pieces of clay to sand,
to pebbles, and to stuff as big as boulders
Clastic rocks form in a process called lithificaton which
means compaction and cementation are occurring
Here’s How They Form:
•Layers of sediment are deposited at the bottom of oceans
and lakes
•As the layers build one on top of another, the pressure on
the bottom layers COMPACTS the sediments together
•In the empty spaces between sediments, natural glues, like
calcite, CEMENT the sediments together
Demo
of
Sedimentator
Look at the processes
that are occurring in
this animation
Clastic Process
Examples of clastic sedimentary rocks include
CONGLOMERATE
SHALE
BRECCIA
SANDSTONE
2. Non-Clastic contain 2 types:
chemical and biochemical
CHEMICAL Sedimentary Rocks are made from mineral
crystals that formed from chemicals dissolved in water.
Here’s How They Form:
•The water in the oceans, lakes,
and underground is often full of
dissolved minerals like halite and
calcite.
•Water evaporates leaving the
solids behind: rock salt is formed
when salt is left after evaporation
and limestone is formed when
calcite is left behind
Chemical Sedimentary Rocks are also formed in caves
where mineral-rich water drips from the ceiling, creating
stalactites and stalagmites made out of limestone
Limestone
Limestone Cave
Examples of chemical
sedimentary rocks
include limestone and
rock salt
BIOCHEMICAL OR ORGANIC Sedimentary Rocks are
made from remains of once-living plants or animals
(organic matter)
•will be found near areas of lots of biological activity
•this is the sedimentary rock type with the most fossils
Biochemical sedimentary rocks include: coquina, chalk,
coal and limestone
COQUINA
Made from
shells
CHALK
Made from dead
animals
COAL
Made from
dead plants
LIMESTONE
with
fossils in it
AMAZING EARTH SCIENCE FACTS
1. Sedimentary rocks form 3 ways:
Clastic- --compacted & cemented
1. _________
2. Chemical
Biochemical
3. _______________
layers or strata.
2. Sedimentary rocks are found in flat _________
3. _______
Fossils are found in Sedimentary Rocks.
Limestone formed both chemically and organically.
4. ____________is
5. Clastic rocks are made of _____________,
sediments examples
are conglomerates, sandstone and shale
6. Chemically formed sedimentary rocks form from
evaporating ocean water, which leaves behind
_____________
rock salt
evaporates like ___________.