Geology Chapter 5 MG
What are shield volcanoes generally made of?
Basalt flows
What is the range of shield volcano height?
300 to 10,000 meters
What is the range of dome complex height?
500 to 2,000 meters
_____ has a rough, broken surface. It is caused by rapidly moving basalt that cools quickly.
Aa flow
What information do geologists use to classify volcanoes?
Shape and type of deposits
Rhyolitic composition
Silica-rich lava, slow lava flow, 1% of lava on Earth
In order to cover such large expanses of seafloor, shield volcanoes erupt _____ lava.
Basaltic
_____ has a rough surface composed of smooth-sided fragments. It is formed by viscous lava cooling quickly.
Block lava
Asthenosphere
Magma with the highest temperature
What type of volcanism characterizes the ring of fire?
convergent oceanic-continental and convergent oceanic-oceanic boundaries
Lavas erupting from composite cones are generally _____-rich, making them very viscous.
Silica
What drives melting at divergent boundaries?
Decompression melting
What type of boundary is present along the eastern boundary of the North American plate?
Divergent oceanic-oceanic
Basaltic composition
Fast lava flow, flows in sheets, 90% of lava on Earth.
What type of magma erupts out of dome complexes?
Felsic magma
Andesitic composition
Intermediate lava flow
_____ results from a relatively fluid lava cooling and forming an outer shell. The lava continues to flow inside the outer shell.
Lava tube
Upper Lithosphere/Crust
Magma with density equal to or less than the crust. Magma undergoing degassing during an eruption. Magma with greatest silica content.
Lower Lithosphere
Magma with density less than the lower lithosphere but higher than the crust. Magma undergoing partial crystallization of high-density minerals.
Based on the structure of the cone and the rock making it up, what interpretations can be made about the gas content of eruptions from cinder cone volcanoes compared to those of shield volcanoes?
More gas than shield volcanoes
At what tectonic setting is Hawaii located?
Oceanic hot spot
In general, how often do most cinder cones erupt?
Only once
_____ has a smooth, billowy surface. It is caused by slowly moving basalt that is still hot.
Pahoehoe flow
_____ is composed of solid, bubble-like masses. It is caused by extremely quick lava quenching.
Pillow lava
Cinder cones are made of _____.
Pyroclastic deposits
What are composite volcanoes made of?
Pyroclastic deposits
What type of volcanoes are the highest?
Shield volcanoes
Why are shield volcanoes wider than composite volcanoes?
The lava that flows out of shield volcanoes is more fluid than the lava that flows out of composite volcanoes.
Which of the following tectonic settings does NOT produce volcanism.
Transform boundary
Nonexplosive eruption
Volcano fed by mafic (basaltic) magma. Volcano fed by high temperature (1,000*C) magma. Volcano fed by magma with low amounts of dissolved gases.
Explosive eruption
Volcano fed by silica-rich magma.