Orosirian

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/orosirian

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 geologic period?Orosirian
2. What is the chronometric boundaries?2050 to 1800 million years ago
3. Why did so many mountains form during the Orosirian?The continents collided and moved fast, causing intense pressure and heat that folded rocks into mountains across almost all land.
4. What happened at the Vredefort and Sudbury impact sites?Two huge space rocks struck Earth, creating the biggest impact basins we know. The Vredefort impact was about 10‑15 km wide and released energy like billions of atomic bombs, while the Sudbury impact happened later around 1.85 billion years ago.

Orogeny: The process of mountain formation, especially by folding and faulting of the Earth's crust.
Chronometric Dating: Determining the age of rocks and geological events using radioactive decay.
Stratigraphy: The study of rock layers and their sequences to understand Earth's history.
Plate Tectonics: The theory that Earth's outer shell is divided into plates that glide over the mantle.