Readworks: Rise of Oxygen

What is the main focus of Grant Young and Jay Kaufman's research?

• The rise of oxygen in Earth's early atmosphere

• The formation of the Huronian Supergroup

• The study of ancient fossils

• The effects of ultraviolet radiation on Earth

What is the Huronian Supergroup?

• A massive formation of rock from 2.5 to 2.2 billion years ago

• A group of scientists studying Earth's atmosphere

• A type of ancient fossil

• A geological period known for volcanic activity

How do geologists study the ancient atmosphere according to the passage?

• By examining rock formations and their composition

• By collecting samples of ancient air

• By studying ancient fossils

• By using a time machine

What is the significance of 'redbeds' in geological studies?

• They indicate the presence of atmospheric oxygen

• They are a type of ancient fossil

• They are formed by volcanic activity

• They are unrelated to atmospheric studies

What method did James Farquhar use to date the rise of oxygen?

• Studying sulfur isotopes in rocks

• Examining redbeds

• Analyzing ancient fossils

• Measuring ultraviolet radiation levels

What change in sulfur isotopes indicates the rise of oxygen?

• A constant ratio of sulfur-33 to sulfur-32 in younger rocks

• A decrease in sulfur-32 levels

• An increase in sulfur-34 levels

• A variable ratio of sulfur-33 to sulfur-32 in younger rocks

According to the passage, when did free oxygen begin to accumulate in the atmosphere?

• About 2.45 billion years ago

• About 3 billion years ago

• About 1 billion years ago

• About 2 billion years ago

Explain what scientists might be able to learn about the seawater that existed millions of years ago by studying rocks that came into contact with seawater at that time in the past. Use evidence from the text to support your inference. (ACE Strategy)