MASC 619: The Rock Cycle

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the significance of Bowen's reaction series in explaining igneous mineral and textures?

It forms the basis for explaining igneous mineral and textures

What determines the texture of an igneous rock?

The temperature of the cooling magma

How do igneous rocks differ based on their composition?

By their silica content, resulting in mafic, felsic, or ultra-mafic rocks

What is the term for the original rock before metamorphism?

Protolith Signup and view all the answers

What is the difference between low-grade and high-grade metamorphic rocks?

Original textures are preserved in low-grade, but not in high-grade metamorphic rocks Signup and view all the answers

What factor determines the colour of an igneous rock?

The dominant minerals present in the rock Signup and view all the answers

What is the significance of magma chemistry in igneous rock formation?

It determines the type of minerals that form, resulting in different types of igneous rocks Signup and view all the answers

What is the difference between intrusive and extrusive igneous rocks?

Intrusive rocks cool slowly and have a phaneritic texture, while extrusive rocks cool quickly and have a glassy or aphanitic texture Signup and view all the answers

What is a rock and how is it defined?

A rock is a naturally occurring solid cohesive aggregate of one or more mineral or mineral materials. Signup and view all the answers

Why do sedimentary rocks make up the majority of the Earth's crust?

Because they are mainly found on ocean floor basins, which account for 70% of the total area of the Earth. Signup and view all the answers

What are the three processes that can cause the melting of rocks to form magma?

An increase in temperature, a decrease in pressure, or a change in composition. Signup and view all the answers

What is the main difference between plutonic and volcanic igneous rocks?

Plutonic rocks cool and crystallize slowly within the Earth's crust, while volcanic rocks form from magma reaching the surface. Signup and view all the answers

What is the name of the process by which rocks are formed, transformed, and destroyed?

The rock cycle. Signup and view all the answers

What are the three main categories of rocks based on their process of formation?

Igneous, sedimentary, and metamorphic rocks. Signup and view all the answers

Why is it important to study rocks and the rock cycle?

Because rocks provide valuable information about the Earth's history, composition, and processes. Signup and view all the answers

What is the term for the solidification and cooling of magma to form rocks?

Igneous rock formation. Signup and view all the answers

Study Notes

What is a Rock?

A rock is a naturally occurring solid cohesive aggregate of one or more mineral or mineral materials.
There are three main rock types: igneous, sedimentary, and metamorphic rocks.

Importance of Rocks

Sedimentary rocks make up 66% of the Earth's crust, with 34% being igneous and metamorphic.
Igneous rocks form the majority of the 34%.
Sedimentary rocks are mainly found on ocean floor basins, which account for 70% of the total area of the Earth.

Igneous Rocks

Formed from the solidification and cooling of magma, which can be derived from partial melts of pre-existing rocks in either a planet's mantle or crust.
Melting of rocks is caused by an increase in temperature, a decrease in pressure, or a change in composition.
Divided into two main categories: plutonic (intrusive) rock and volcanic (extrusive).
Plutonic rocks result from magma cooling and crystallizing slowly within the Earth's crust, e.g., granite.
Volcanic rocks result from magma reaching the surface either as lava or fragmental ejecta, e.g., pumice or basalt.
Bowen's reaction series explains the sequence of crustal formation and forms the basis for explaining igneous mineral and textures.
Can be differentiated according to their texture, color, and composition depending on the environment of deposition and the chemistry of magmas.

Texture of Igneous Rocks

Determined by the temperature of the cooling magma.
Slow cooling: large crystals form, phaneritic texture.
Fast cooling: small crystals form, sometimes a glassy texture where no minerals form.

Color of Igneous Rocks

Determined by its dominant minerals.
Dark minerals form mafic rocks, while lighter colored minerals form felsic rocks due to fractionation during magma cooling.

Metamorphic Rocks

Formed due to high pressure and temperature below the zone of diagenesis.
Protolith refers to the original rock, prior to metamorphism.
Original textures are often preserved in low-grade metamorphic rocks, allowing one to determine the likely protolith.
Grade of metamorphism increases with pressure and temperature.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the rock cycle, main characteristics of igneous, sedimentary, and metamorphic rocks, and why there is an active rock cycle on Earth. Discover the processes that lead to the formation of different types of rocks.