Igneous Processes and Volcanoes

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Questions and Answers

What is one possible outcome when felsic magma rises?

It may cool into a granitic batholith. (correct)

It tends to dissolve into the mantle.

It can completely solidify into a basalt layer.

It will always lead to the formation of a mafic volcano.

What is the primary reason for the generation of magma at subduction zones?

The release of water from hydrated minerals (correct)

The rising temperature of the mantle

The addition of water from surface sources

The melting of the tectonic plates

What characterizes intraplate volcanism related to a hotspot?

It forms chains of extinct volcanoes connected to eruption zones. (correct)

It is only confined to oceanic plates.

It is solely dependent on tectonic plate boundaries.

It typically forms parallel volcanic chains.

What type of magma is primarily produced from subduction-related volcanism?

Intermediate-to-felsic magma Signup and view all the answers

Which statement accurately describes the Hawaiian Islands in relation to hotspot volcanism?

They represent the active portion of a longer volcanic chain. Signup and view all the answers

Which geological feature is most commonly associated with subduction volcanism?

Volcanic arcs Signup and view all the answers

What process contributed to the formation of the Yellowstone caldera?

The North American plate moving over a hotspot mantle plume. Signup and view all the answers

At continental rifts, what leads to volcanic activity?

Decompression of rising magma Signup and view all the answers

Which of the following describes the geological significance of the Emperor Seamounts?

They represent a long extinct volcanic chain associated with hotspot volcanism. Signup and view all the answers

In the context of volcanism, what characteristic of magma produced at continental rifts differs from that at subduction zones?

It is less dense Signup and view all the answers

What is the primary cause of cinder cone eruptions in the Black Rock Desert?

Crustal extension in the Basin and Range Signup and view all the answers

How long ago did the most recent eruption of the cinder cones in Utah occur?

720 years ago Signup and view all the answers

What defines a hotspot in the context of intraplate volcanism?

A site where lithospheric plates move over a hot mantle plume Signup and view all the answers

What typically happens when ascending magma from a mantle plume reaches the lithospheric crust?

It spreads out into a mushroom-shaped head Signup and view all the answers

Why do most mantle plumes mainly occur beneath oceanic lithosphere?

Oceanic plates are thinner and move more easily Signup and view all the answers

Study Notes

Igneous Processes and Volcanoes

Bowen's Reaction Series: Key relationship between minerals and temperature in igneous rocks. Certain minerals always form together and exclude others, depending on cooling temperature. Bowen's experiments showed this. Mafic minerals crystallize at higher temperatures than felsic minerals.
Magma Generation: Magma comprises melt, solids, and volatiles. Melt is minerals that liquefied; solids are crystallized minerals in the melt; volatiles include water vapor, carbon dioxide, sulfur, and chlorine. These components influence magma's behavior.
Geothermal Gradient: Earth's temperature increases with depth. The average geothermal gradient in the upper 100 km of the crust is 25°C per kilometer of depth. The temperature at any depth depends on pressure. Higher pressure increases the melting temperature of rocks.
Volcanism: Molten rock (lava) reaching Earth's surface. Volcanoes form where lava solidifies. Volcanoes are categorized based on location (interplate or intraplate), type, hazards, and monitoring.
Interplate Volcanoes: Located at active plate boundaries (mid-ocean ridges, subduction zones, and continental rifts). These include most mid-ocean ridge volcanoes, with basalt being the most common type of rock.
Intraplate Volcanoes: Located within tectonic plates, away from plate boundaries. Many are associated with hotspots. Hotspots are stationary sources of magma in the mantle.
Volcano Features and Types: Volcanoes vary in shape, eruption style, and composition. Different types include shield volcanoes, stratovolcanoes, cinder cones, and calderas.
Volcanic Hazards: Lava flows, pyroclastic flows (hot gas and rock), lahars (volcanic mudflows), landslides, and volcanic gases.
Volcanic Monitoring: Techniques used to predict eruptions, such as analysis of earthquake activity, gas emissions, and ground deformation.

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Description

Explore the fascinating world of igneous processes and volcanism through this quiz. Understand key concepts like Bowen's Reaction Series, magma generation, and geothermal gradients. Test your knowledge on how these processes shape our planet's geology.