What Are Metamorphic Rocks?
Are you looking for an easy way to teach your child about rocks and minerals? We’ve put together a set of free materials that parents and teachers can use right away. In this lesson, your child will dive into the fascinating world of the rock cycle.
We’ll explore the transformation of rocks between different types. Explore science in a more engaging way with captivating 3D videos and interactive quizzes. Download our app to get started!
Table of Contents
What you will learn from this lesson
- Gneis and marble are metamorphic rocks.
- The rock cycle shows how rocks transform into each other.
- Gneiss forms from granite by metamorphism.
- Marble can form from limestone through metamorphism.
Metamorphic rocks are a classification of rocks formed through metamorphism. The name comes from their formation process, as metamorphism changes a rock into a different type. Two examples of metamorphic rocks are gneiss and marble.
How Does Gneiss Form?
Gneiss is a type of metamorphic rock that begins as granite. The formation process occurs due to plate motions on Earth. When the Earth’s plates collide, the resulting high temperatures and pressure transform granite into gneiss. This transformation is known as regional metamorphism. The intense heat and pressure cause minerals to arrange into the layered bands seen on gneiss. Regional metamorphism can also form mica schist, which might contain minerals like staurolite and garnet.
How Does Marble Form?
Marble is another type of metamorphic rock, often beginning as limestone, which is a sedimentary rock. Marble can form through two processes: contact metamorphism or regional metamorphism. Contact metamorphism occurs when magma intrudes and heats the limestone, causing the rock to transform under high pressure and heat. During this process, the main mineral in limestone and marble, calcite, gets bigger.
What is the rock cycle？
The transformation between magma and different types of rocks is known as the rock cycle. Igneous, sedimentary, and metamorphic rocks can all transform into each other.
- When magma cools down, it forms igneous rock.
- Surface rocks, such as igneous rocks, can turn into sedimentary rocks through weathering.
- Metamorphism changes these rocks into metamorphic rocks.
- Through plate movements, all types of rocks can return underground and become magma again.
Fun Fact
- Metamorphic rock can be formed by intense heat and pressure when the Earth’s giant plates collide.
- Dull limestone can magically turn into beautiful, sparkling marble under heat and pressure, like a caterpillar becoming a butterfly.
- Through plate movements, any type of rock can return underground to melt and become magma again.
Vocabulary
- Rock Cycle: The continuous process in which igneous, sedimentary, and metamorphic rocks transform into one another. It describes how rock material circulates between different rock types and magma.
- Metamorphism: The process that transforms existing rocks into metamorphic rocks under intense heat and pressure.
- Igneous Rock: A type of rock formed when hot magma cools down and solidifies, either within the Earth’s crust or on the surface.
- Sedimentary Rock: A rock type formed from surface rocks, which are often the result of weathering, such as limestone.
- Metamorphic Rock: A rock type, like gneiss or marble, that is created when another rock undergoes metamorphism due to heat and pressure.
- Regional Metamorphism: A type of metamorphism that occurs when tectonic plate movements create high temperatures and pressure, transforming rocks like granite into gneiss.
- Contact Metamorphism: A type of metamorphism where a rock, such as limestone, is transformed into marble primarily by the heat from an intruding body of magma.
- Magma: The molten material beneath the Earth’s surface that cools down to form igneous rock.