Download Earth-Processes-and-Rock

Earth Processes and Rock Layers
Mountain Building
• Mountain building occurs
when 2 continental plates of
equal densities collide.
– The plates crush together,
causing land to be pushed up
and break.
• Mountain building changes
the shape of Earth’s surface.
Erosion
• Erosion is the wearing away
of material through wind
and water.
• The process of erosion can
expose (uncover) layers of
rock.
Mountains and Erosion
• Over time all mountains will crumble
through erosion.
• Mountain peaks will eventually become
rounded hills.
Glaciers
• Glaciers are slow moving
masses of ice formed from
compacted layers of snow.
• Glaciers move and change with
temperature change, gravity,
and high pressure.
• Glaciers carve out mountains.
• Glaciers move rocks out of
mountains.
Changes to Earth’s Surface
• Erosion, mountain building, and glacier
movement change the surface of the Earth
and earth materials to form layers.
• Rock layers are used to show the geologic time
and history of the Earth.
Rocks and Geologic Time
•The observation and study of rock
layers is used for the measurement of
geologic time.
•The earth has distinct layers of rock
–The rock layers show a progression of
organisms from layer to layer
Principle of Superposition
•Principle of Superposition
–The oldest layer is on the bottom, then
each layer up is younger, with the youngest
layer being on the top
–This is because sediment is deposited on top
of previously existing sediment.
Relative Dating
•Relative dating can be used to estimate the
order of prehistoric and geologic events
•This happens by observing where fossils are
found in layers of rock
–The oldest rock layers contain the oldest fossils and
the youngest rock layers contain the youngest fossils
–A fossil must have existed at the time when the rock
layer was formed, which is how we can tell
Relative Dating
Relative Dating