Black Canyon of the Colorado

High school (ages 12+)
Geography

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/black-canyon-of-the-colorado

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 formation?Approximately 15 million years ago during the Miocene Basin and Range uplift
2. What is the geological composition?Primarily black volcanic rocks, indicative of past igneous activity
3. Why is the canyon called "Black"?The walls are dark because they are made of black volcanic rocks, like basalt, from ancient eruptions.
4. How did Hoover Dam get built in the Black Canyon?Workers dug tunnels into the canyon walls, diverted the river, and used special techniques to hold back water and build a huge concrete dam between 1931 and 1936.

Basin and Range Province: A vast physiographic region in the western United States characterized by numerous north-south mountain ranges and valleys.
Extensional Tectonics: The process where the Earth's crust is pulled apart, leading to faulting and the formation of basins and ranges.
Fluvial Erosion: The process by which a river or stream wears away land and transports sediment.
Geothermal Gradient: The rate at which temperature increases with depth within the Earth's interior.