Download Topic 6 Notes- Volcanoes - École St. Joseph School

Topic 6 Notes- Volcanoes
A volcano is an opening in the Earth’s crust that releases lava, steam
and ash when it erupts. These openings are called vents. When volcanoes are
not active (they do not erupt) they are called dormant. Like earthquakes,
volcanoes can be formed when rock surfaces beneath the earth’s crust push
against one another.
Famous volcanoes are as follows: Mt. St. Helens, Mount Pinatubo and
Mt. Vesuvius. These volcanoes and more have lined up on the pacific ocean
and make up the RING OF FIRE. Most volcanoes in the Ring of Fire occur
at subduction zones.
Topic 7- Mountains
Mountain building takes years to form but can create beautiful
scenery. The Canadian rockies, the American Rockies and the mountains in
Alaska all contribute to form the Western Cordillera. Most mountains are
large areas that have been uplifted due to movement or heating of plates.
When heated, rock can actually be quite pliable and bend like metal, which
is why we have folds in mountains. The top part of the fold, is called the
anticline. The ridge is called the syncline.
Thrust faulting- is when sedimentary rock is squeezed from the sides
of a fault. The mountains that form from this process are known as fault
block mountains.
It is extremely important to understand and memorize the 8 different
mountain ranges and where they can be located on a map. The Alps, Urals,
Andes, Himalayas, Carpathians, Great Dividing Range, Rockies and
Laurentians.