Science 8
Fresh & Saltwater Systems
2.3-Processes Shaping Oceans
I can define the term lithosphere and describe the processes that influence its shape.
I can describe the geological features of the ocean floor and describe how they are formed.
I can describe glaciers and glacial features.
Earth is _____________________________________ years old! It is in a _____________________ state of change.
The lithosphere is the ___________________________________ of the Earth. It is made of ___________, which
has been broken into huge, moving pieces called tectonic plates.
Plate Tectonics
These tectonic plates move constantly and slowly by ___________________________________ within Earth.
The movements of the plates have shaped the geological features on the ______________________________
and many of those on the _______________________________.
Geological Features on the Ocean Floor Due to Plate Tectonics

Mid-ocean ridges

Seamounts

Continental shelves

Trenches

Volcanic islands
Mid-Ocean Ridges form where molten rock __________________________ from the interior of the Earth.
On either side of the ridge are two different plates that are slowly _______________________ from each
other as the molten rock hardens into _______________________________.
The continental shelves are ______________ areas around the ___________ of continents. They are
mainly sedimentary deposits of materials __________________________ the continents.
Volcanic islands are formed by volcanoes that grow up from the _____________________________________.
Seamounts are _____________________________________________________ that do not come all the way to the
ocean’s surface.
1
Science 8
Fresh & Saltwater Systems
Trenches are long, deep ____________________________ in the ocean bed. They form where two plates
are moving ________________________ each other.
Continental Drainage Systems
The same forces that shape the __________________________ also build the continental divides. At the
edge of the continent, two plates meet and push against each other, which cause ________________ in
the continents’ surfaces and ___________________________. Plate tectonics have formed many
continental divides.
Glaciers
Glaciers are large moving bodies of _________.
Continental glaciers (or icecaps) are glaciers that cover vast areas of land.
Valley glaciers are glaciers that form high up in mountain ranges. Snow
and ice build up and then begin to move. These glaciers flow down between the
____________________________. These glaciers collect __________________________________, which drag on the
surface and determine the form of the land.
The movement of glaciers depends on the _____________________.
 _________________ = little melting, snow builds up. The glacier is said to be _______________________
(moves forward).
 __________________= more melting, snow melts. The glacier is said to be __________________________
(moves backward).
Glaciers always flow ___________________________.
Ice Ages
Today we have ________ continental and valley glaciers that cover the Earth. In the past, large areas
of the Earth were covered with glaciers. This was the times of the Ice Ages. The Ice Ages shaped
______________ of Canada’s geography.
Glacial Features (see p. 364)
As glaciers advance and retreat, they leave many structures:
1) Moraines, 2) Eskers, 3) Drumlins, 4) Kettle lakes.
2