Download Lesson 12 - Intra Plate Volcanism

Plate Boundary Volcanism
 Volcanoes are associated with two of the three
types of plate boundaries, these being convergent
and divergent boundaries. Very little volcanic
activity is seen at transform fault boundaries.
 Volcanism associated with plate tectonic
activity are found in three areas on Earth;
1) Ridges (or spreading centers)
Reference:
2) Subduction zones
3) Interior of tectonic plates.
Tarbuck and Lutgens
Pages 232 - 235
Intraplate Volcanism
 This type of volcanism is produced by rising hot
mantle material called Hot Spots. Hot spots can be
found under continents and the ocean floor.
 Intraplate volcanism occurs in two areas;
1) beneath the oceans (Hawaiian Islands)
2) within continental plates (Yellowstone National Park)
Intraplate Volcanism
1) Beneath Oceans
 Hotspots within the mantle cause magma to move
upward and flow onto the ocean floor forming shield
volcanoes and volcanic islands.
Magma
 An example includes the Hawaiian Islands.
Intraplate Volcanism
2) Within Continents
 Hotspots within the mantle cause magma to move
upward and flow onto the continental surface forming
volcanoes and lava plateaus.
 Yellowstone National Park has this type of volcanism.
Sample Problem
With the aid of a labelled diagram explain how the Hawaiian
Island Chain formed.
Answer:
Younger
Older
Ocean Plate
Hot
Spot
The Pacific plate moved over a stationary
hot spot, forming new volcanic islands
directly over the hot spot. The older
volcanic islands move with the Pacific
plate and travel farther away form the
hotspot with each passing year. Over a
period of time a chain of islands form.
The older islands are no longer fed by the
hot spot and therefore become dormant
(extinct) or inactive volcanic islands.