Metamorphic rocks form when existing rocks undergo transformation due to... Show more
Environmental Science22 views·Updated May 21, 2026·2 pagesMetamorphic Rocks and Rock Classification - Geology Notes Lesson 8
Mariah@mariah_stangl
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Metamorphic Rock Formation
Ever wonder how rocks change without melting? That's metamorphism! A protolith (original rock) transforms into a metamorphic rock through pressure, temperature, and fluids - with no melting involved.
Pressure increases with depth due to the weight of overlying rocks (up to 300 MPA). Similarly, temperature rises with depth from geothermal heat. Fluids come from water trapped in cracks or contained within minerals. When a protolith experiences some partial melting, it becomes a migmatite.
During metamorphism, rocks undergo several changes. Compaction eliminates air spaces, creating denser rock. Recrystallization rearranges elements to form more stable minerals. Minerals develop a preferred orientation as they realign during compaction. Metasomatic processes involve water and heat bringing additional elements.
Remember This! Metamorphic rocks form in two main settings: regional metamorphism (affecting large areas at convergent plate boundaries) and contact metamorphism (where magma heats adjacent rock).
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Metamorphic Rock Classification
Metamorphic rocks come in two main types: foliated and non-foliated. You'll ace identifying them once you know the differences!
Foliated rocks show preferred orientation of minerals. They follow a progression based on increasing pressure and temperature: shale (a sedimentary rock) transforms to slate , then phyllite , then schist , and finally gneiss .
Non-foliated rocks don't show this alignment. Quartz sandstone becomes quartzite (hard enough to scratch glass), while limestone transforms into marble (fizzes in acid due to calcite content). These transformations often occur at convergent boundaries where oceanic lithosphere meets continental lithosphere.
Pro Tip: When identifying metamorphic rocks, look for foliation patterns first, then check specific properties like grain size and mineral composition to determine exactly which type you have.
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Environmental Science22 views·Updated May 21, 2026·2 pagesMetamorphic Rocks and Rock Classification - Geology Notes Lesson 8
Mariah@mariah_stangl
Metamorphic rocks form when existing rocks undergo transformation due to pressure, temperature, and fluids - without actually melting. Understanding these processes helps us identify how Earth reshapes its materials over time, creating distinct rock types with unique properties.
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Metamorphic Rock Formation
Ever wonder how rocks change without melting? That's metamorphism! A protolith (original rock) transforms into a metamorphic rock through pressure, temperature, and fluids - with no melting involved.
Pressure increases with depth due to the weight of overlying rocks (up to 300 MPA). Similarly, temperature rises with depth from geothermal heat. Fluids come from water trapped in cracks or contained within minerals. When a protolith experiences some partial melting, it becomes a migmatite.
During metamorphism, rocks undergo several changes. Compaction eliminates air spaces, creating denser rock. Recrystallization rearranges elements to form more stable minerals. Minerals develop a preferred orientation as they realign during compaction. Metasomatic processes involve water and heat bringing additional elements.
Remember This! Metamorphic rocks form in two main settings: regional metamorphism (affecting large areas at convergent plate boundaries) and contact metamorphism (where magma heats adjacent rock).
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Metamorphic Rock Classification
Metamorphic rocks come in two main types: foliated and non-foliated. You'll ace identifying them once you know the differences!
Foliated rocks show preferred orientation of minerals. They follow a progression based on increasing pressure and temperature: shale (a sedimentary rock) transforms to slate , then phyllite , then schist , and finally gneiss .
Non-foliated rocks don't show this alignment. Quartz sandstone becomes quartzite (hard enough to scratch glass), while limestone transforms into marble (fizzes in acid due to calcite content). These transformations often occur at convergent boundaries where oceanic lithosphere meets continental lithosphere.
Pro Tip: When identifying metamorphic rocks, look for foliation patterns first, then check specific properties like grain size and mineral composition to determine exactly which type you have.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in Environmental Science
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha KlichAndroid user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
AnnaiOS user