it's present in the pore spaces of some rocks and can be bound in the crystal structure of some minerals
How is water present in rocks and minerals?
1 small.......2 low......3 quiet..
Basaltic magma contains__1___ amounts of silica and has __2___ viscosity and fuels relatively ____3__eruptions
viscosity increases with a decrease in temperature
How does the viscosity of magma change as magma cools?
magma high in silica has a higher viscosity than magma low in silica
Is the viscosity of magma that is high in silica higher or lower than magma that is lower in silica?
basaltic lava flows faster because basaltic lava has less silica
Which type of lava-basaltic lava or rhyolitic lava-flows faster? Explain.
western coasts of N and S America and down the eastern coast of Asia
circum pacific belt stretches along the
slabs of oceanic crust descend into mantle and melt; magma that forms is forced upwards and volcanoes form
how do volcanoes form?
1 high temperature plumes melting the rock which causes magma to move upward and cause volcanoes
2 from the formation of flood basalts (outpourings of basalt lava) which erupt from fissures to form a flat plain or a plateau instead of volcanic mountains
hot spots can forms from_____1____and ______2_____
under water along ocean ridges
most volcanoes that are formed along divergent plate boundaries are___________
-composite volcano-in between cinder and shield, forms with layers of tephra and lava, has lots of silica, water and gases, most dangerous type of volcano
-cinder-cone volcano-small and steep, formed from tephra being thrown in air and then piling up around vent, lava has higher silica and water than shield volcanoes but still not a lot, contains a large volume of gases
-shield volcano-really big and sloped, lava has small amounts of gas and silica, forms when layers of basaltic lava accumulate during a non-explosive eruption
3 types of volcanoes