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

Andesitic composition

Intermediate lava flow

What information do geologists use to classify volcanoes?

Shape and type of deposits

What type of volcanoes are the highest?

Shield volcanoes

Lavas erupting from composite cones are generally _____-rich, making them very viscous.

Silica

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

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

_____ 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.

Asthenosphere

Magma with the highest temperature

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

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.

What type of volcanism characterizes the ring of fire?

convergent oceanic-continental and convergent oceanic-oceanic boundaries