Basalt

High school (ages 12+)
Environment & Earth

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/basalt

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 classification?Aphanitic extrusive igneous rock
2. What is the magma composition?Mafic, with silica content between 45% and 52%
3. Why does basalt have a fine-grained texture?Because the lava cools fast at or near the surface, so crystals don't have time to grow large.
4. Where can we find basalt on Earth?Basalt makes up the ocean floor, big volcanic plains, and shield volcanoes, and most of Earth's volcanic rocks are basalt.

Aphanitic Texture: A fine-grained texture in igneous rocks where mineral crystals are too small to be seen with the naked eye.
Mafic: Refers to igneous rocks rich in magnesium and iron, and relatively low in silica.
Viscosity: A measure of a fluid's resistance to flow; low viscosity means it flows easily.
Extrusive Igneous Rock: Rock formed from lava that cools and solidifies on the Earth's surface.