OG Module 13 Quiz

Sonar uses sound waves to measure water depth.

• True
• False

Maps made from sonar and magnetometer data led to the discovery of ocean ridges and deep-sea trenches.

• True
• False

Rock samples taken near ocean ridges are older than rock samples taken near deep-sea trenches.

• True
• False

The thickness of ocean-floor sediments decreases with distance from an ocean ridge.

• True
• False

Earthquake activity and volcanism are common along ocean ridges.

• True
• False

The theory of seafloor spreading explains that Earth’s continents move because they ride atop ocean crust as it moves away from ocean ridges.

• True
• False

This is Wegener’s hypothesis that Earth’s continents were joined as a single landmass, called Pangaea, that broke apart about 200 mya and slowly moved to their present positions

• convection currents
• continental drift
• plate tectonics
• seafloor spreading

This is an ancient landmass made up of all the continents that began to break apart about 200 mya

• pangaea
• north america
• jurassic period
• Laurentia ice sheet

This is a device used to map the ocean floor that detects small changes in magnetic fields

• sonar
• scuba gear
• isochron
• magnetometer

This is when Earth’s magnetic field changes polarity between normal and reversed

• magnetic reversal
• solar flair
• seafloor spreading
• milankovitch cycle