Magma
What is lava?
Lava is magma that flows out onto Earth's surface.
what are the three main kinds of landforms created by the eruptions of volcanoes?
3 main types of volcanic landforms: Shield, Composite, and Cinder Cones
What is Magma?
Molten rock beneath the Earth's surface.
Where do most volcanoes occur?
Most volcanoes, like most earthquakes, occur along the boundaries between shifting tectonic plates.
What type of eruptions occur with basaltic magma?
Basaltic magma is less viscous, gases release easily and eruptions are effusive or non-exploding?
When does magma form?
Decrease in pressure lowers melting temperature of materials (divergent) OR increase in amount of water can lower melting temperature of materials (subduction) OR increase in temperature can cause materials to melt (hot spot), depending on where it is forming.
What is a cinder cone volcano?
This type of volcanic landform is made up of small rock particles, or cinders. It is characterized by a small cone with steep sides.
High silica lava has what viscosity?
High silica lava is more viscous and resists flow.
What is a Subduction Boundary?
Subduction boundary is where two plates collide and one goes under the other.
What is pahoehoe?
Rock formed from basaltic lava at high temperatures cooling slowly forming smooth ropelike surfaces.
Why does magma rise?
Magma rises because it is less dense than the solid rock around it.
What is a shield volcano?
This type of volcano is made up of layers of basaltic lava, created slowly that's why it has gentle slopes and broad sides.
What is a hot spot?
A region of volcanic activity in the middle of a tectonic plate.
What is a Divergent Boundary?
Divergent boundary is where plates are moving apart.
What type of eruptions occur with more viscous andesitic, dacite and rhyolitic magma?
Explosive eruptions
What is viscosity?
Resistance to flow due to silica content.
What is a composite volcano?
This type of volcanic landform is conical in shape and made up of layers of lava flows.
What is pillow lava?
Lava that cools underwater.
What plate boundaries do we have close in BC?
Subduction, divergent and transform boundaries.
What is aa?
Rock formed from low temperature lava that cools quickly in rough, jagged surfaces
Where does gas enter magma?
Gases enter at depth and are released as it rises.
Which type of volcanic landform is the most destructive? Name a volcanic landform that was developed this way.
Composite volcano. Mt. St. Helens is a composite volcano.
What is the Ring of Fire?
A zone of frequent earthquakes and volcanic eruptions that encircles the Pacific Basin.
How do hot spots form new land? Name a landform created by hot spots.
Hot spots erupt and release magma. As magma comes out it becomes lava and hardens into landforms. Hawaiian islands are created by hot spots.
What is pyroclastic material?
Solid fragments from release of gases.