Optional Extra Credit: Seafloor Spreading

What is seafloor spreading?

• A process where new oceanic crust is formed at mid-ocean ridges and moves away from the ridge

• The movement of Earth's lithospheric plates

• The formation of hydrothermal vents

• The creation of trenches on the ocean floor

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

What evidence supports the Plate Tectonics Theory?

• Analysis of sediment layers and radioactive decay in rocks

• The presence of hydrothermal vents

• The elevated position of mid-ocean ridges

• The creation of trenches

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

What do magnetic reversals in seafloor rocks reveal?

• Patterns aligning with Earth's changing magnetic field

• The formation of hydrothermal vents

• The age of the ocean floor

• The ridge push mechanism

What is the ridge push mechanism?

• A process where newly formed crust slides away from mid-ocean ridges due to gravity

• The movement of tectonic plates

• The release of mineral-rich water from hydrothermal vents

• The formation of trenches on the ocean floor

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

Where are hydrothermal vents typically found?

• Near mid-ocean ridges

• In trenches

• On the elevated position of ridges

• In sediment layers

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

NGSS.HS-ESS2-3

Label all the parts of this model

a

b

c

d

e

older crust

ocean floor

younger crust

oceanic ridge

magma

Tags

NGSS.HS-ESS2-1

In the Atlantic ocean, where is the youngest seafloor located?

• Towards the edges, near the eastern and western continents
• Towards the middle of the ocean at the mid-ocean ridge

• Towards the north and south poles
• Young seafloor is located randomly throughout the ocean

Tags

NGSS.HS-ESS1-5

NGSS.HS-ESS2-1

How do scientists figure out the age of the seafloor?

• They research it from ancient sea maps that trading vessels would use in the 1700s
• They use the moon phases and eclipses to calculate the age
• They use seismographs and the depth as well as location of earthquakes to calculate the age
• They take drill ships to many locations in the oceans and collect, then date, rock samples. 

Tags

NGSS.MS-ESS1-4

The average density of continental crust is 2.8 g/cm³ and the average density of oceanic crusts is 3.2 g/cm³. If these two plates came together, what would happen?

• The two plates would push apart and form a rift zone.

• The oceanic plate would rise up over the continental plate.

• The oceanic plate would sink under the continental plate.

• The two plates would meet head on and rise up to form mountains.

Tags

NGSS.HS-ESS1-5