What generally happens when subduction-derived magma encounters thick continental crust?

Which of the following are processes that can occur in large magma chambers?

Which of the following are processes that can occur in large magma chambers: –Magma may partially melt the chamber’s rock walls, forming a new magma composition-A partially crystallized magma could be heated by a new, hotter magma entering the chamber– Crystals that form may sink or rise in the chamber 29.

When a rising mantle plume encounters continental lithosphere?

When a rising mantle plume encounters continental lithosphere and melting occurs in the lower part of the lithosphere, the magma produced is mafic magma.

What makes Magma less viscous?

Intermediate magma

They are also commonly hotter, in the range of 850 to 1,100 °C (1,560 to 2,010 °F)). Because of their lower silica content and higher eruptive temperatures, they tend to be much less viscous, with a typical viscosity of 3.5 × 106 cP at 1,200 °C (2,190 °F).

How does the addition of water cause melting quizlet?

How does the addition of water affect the melting temperature of hot rock? When water mixes with hot, dry rock, they cause chemical bonds to break, so that the rock begins to melt. Adding volatiles decreases a rock’s melting temperature.

What mineral will likely melt first?

Rock composition: Minerals melt at different temperatures, so the temperature must be high enough to melt at least some minerals in the rock. The first mineral to melt from a rock will be quartz (if present) and the last will be olivine (if present).

Which of the following are the two main factors controlling volcanic eruption style?

The two main factors that influence how a volcano will erupt are viscosity and gas content. Both are related to the composition of the magma. Hawaiian volcanoes tend to erupt basalt, which is low in viscosity and low in gas content (about 0.5 weight percent).

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Which type of magma has the greatest silica content?


~50% Mafic Basalt
~60% Intermediate Andesite
~65% Felsic (low Si) Dacite
~70% Felsic (high Si) Rhyolite

What is the mantle plume theory?

A mantle plume is an upwelling of abnormally hot rock within the Earth’s mantle. Some scientists think that plate tectonics cools the mantle, and mantle plumes cool the core. Two of the most well known locations that fit the mantle plume theory are Hawaii and Iceland as both have volcanic activity.

Are mantle plumes and hotspots the same thing?

About 95% of the world’s volcanoes are located near the boundaries of tectonic plates. The other 5% are thought to be associated with mantle plumes and hot spots. Mantle plumes are areas where heat and/or rocks in the mantle are rising towards the surface. A hot spot is the surface expression of the mantle plume.

What type of magma has the highest viscosity?

Rhyolitic magmas tend to have even higher viscosity, ranging between 1 million and 100 million times more viscous than water.

What is the most explosive magma?

Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas).

What are the 3 major types of magma?

There are three basic types of magma: basaltic, andesitic, and rhyolitic, each of which has a different mineral composition. All types of magma have a significant percentage of silicon dioxide. Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium.

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Why does the addition of volatiles cause melting?

Volatiles. Rocks melt at a lower temperature in the presence of volatiles such as water and carbon dioxide. As the cold slab sinks, water is forced out and percolates upward into the overlaying hot, dry mantle rock. This sudden addition of water lowers the melting point of that mantle rock, and it begins to melt.

What is the definition of magma mixing quizlet?

Magma mixing. The process of altering the composition of a magma through the mixing of material from another magma body. Melt. liquid portion of magma. Only $2.99/month.

What are the two ways a primary magma can be generated?

Magma is formed by both wet and dry melting processes. By melting different parts of the layers of the earth, basaltic, rhyolitic and andesitic magma will be formed.

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