Transcript Slide 1

Lesson 10
What are sedimentary rocks?
Mount Everest, in Asia, is the
tallest mountain in the world.
Eventually, it will be completely
worn away. In fact, it is wearing
away right now, little by little.
It may take a million years, but
eventually, it will be gone.
Forces of nature, such as wind
and water, keep breaking rocks
and soil into smaller and smaller
pieces.
These broken pieces are called
fragments.
Pebbles, gravel, sand, silt and
clay are 5 kinds of rock
fragments.
Fragments are moved about by
water, wind, and large ice
masses called glaciers.
The fragments settle in a new
place.
The settled fragments are called
sediment.
As time passes, older layers of
sediment are covered by new
layers.
As more and more layers are
added, the lower layers become
tightly packed.
Eventually, they become
hardened rock.
Rock that is formed from
hardened sediments is called
sedimentary rock.
Sediments can harden into
sedimentary rock in two ways:
-from the pressure of its own
weight
-being cemented, minerals
dissolved in water “glue”
sediments together
Most sediment builds up under
water.
Some sedimentary rocks form
from the remains of living things
and shells.
Coal is formed from
layers of dead plant
matter.
Some sedimentary rock was
formed from minerals dissolved
in water.
Sandstone rocks are
sedimentary rocks made from
small grains of the minerals
quartz and feldspar. They often
form in layers.
Limestone rocks are sedimentary
rocks that are made from the
mineral calcite which came from
the beds of evaporated seas and
lakes and from sea animal shells
Gypsum rocks are sedimentary
rocks made up of sulfate mineral
and formed as the result of
evaporating sea water in
massive prehistoric basins.