Gneiss

High school (ages 12+)
Science & Technology

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/gneiss

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the rock type?High-grade metamorphic rock
2. What is the formation pressure range?2 to 15 kbar (kilobars)
3. What is gneiss and why does it have stripes?Gneiss is a metamorphic rock that shows bright and dark layers. The layers form when minerals inside the rock line up and separate during extreme heat and pressure, like playdough being squeezed. The result is a striped, banded texture.
4. How does gneiss form deep inside the Earth?Gneiss forms deep in the Earth's crust where temperatures are above 300°C and pressures are 2 to 15 kilobars. These conditions happen near places where continents collide or in the roots of old mountain ranges. The original rock, whether igneous or sedimentary, changes its minerals and structure as it is heated and squeezed.

High-Grade Metamorphism: Metamorphic processes occurring at high temperatures and pressures, leading to significant mineral recrystallization.
Porphyroblast: A large, often rounded, metamorphic mineral crystal that grew within the finer-grained matrix of a metamorphic rock.
Orogenic Belt: A region of the Earth's crust that has been deformed and metamorphosed during mountain building, typically associated with plate collisions.
Craton: A stable, ancient block of the Earth's crust, forming the nucleus of a continent.