Exam 6: Volcanoes and Other Igneous Activity

In what plate tectonic setting are magmas generated predominantly by fluids from ocean waters in trenches "fluxing" the melting process by decreasing melting temperature?

Match the letter on the figure with the term. -Identify what letter A represents in the diagram.

Dissolved gases may comprise up to_______ of a magma.

Where can we find the most active volcanoes in the world?

_______is the major dissolved volatile constituent in both magmas and volcanic gases.

Which of the following is considered pyroclastic debris?

What is the connection between the amount of silica in a melt and how viscous it is?

Pyroclastic flows move_______ .

Magmas are generated at mid- ocean ridges by _______melting.

Which of the following best describes Shiprock, a famous volcanic feature in New Mexico?

Volcanoes are generally not preserved in the geologic rock record because the upper part of the volcano is eroded away. However, the igneous rocks associated with volcanoes are often found preserved in the rock record as layers of volcanic rock and associated intrusions. How could you infer what type of volcano erupted in a given area based on the type of volcanic deposits? Give specific examples and briefly discuss if some materials may be linked to different types of volcanoes.

The viscosities of magmas _______with increasing percentages of silica.

The famous destruction of the Roman city of Pompeii was produced by_______ .

The main mechanism for melting at spreading ridges is_______ .

Note the image showing a series of batholiths on the landscape. How did those batholiths get exposed at the surface?

Match the letter on the figure with the term. -Identify what letter B represents in the diagram.

Paricutin volcano in Mexico is an example of a _______ .

The rock pumice often floats yet the density of the rock is greater than water. Why does it float?

What type of volcanic material is indicative of eruption under water?

The average composition of rocks comprising a large composite cone or stratovolcano is generally_______ .