Ocean Formation

Which of these happens first?

• The less dense material flows sideways, carrying the seafloor away from the ridge in both directions

• Hot, less dense material below Earth's crust rises towards the surface at a mid-ocean ridge.

• As the seafloor spreads apart, magma is forced upward and flows from the cracks. The lava cools to form new seafloor.

What is the first step of sea-floor spreading?

• the molten material cools and hardens, forming a strip of rock along the ocean floor.

• the strip of rock moves away from the ridge.

• molten material from inside Earth rises to the ocean floor at a mid-ocean ridge.

• What?

Tags

NGSS.MS-ESS2-1

Molten material from inside Earth rises to the ocean floor at a mid-ocean ridge. Then .....

• the molten material cools and hardens, forming a strip of rock along the ocean floor.

• the strip of rock moves away from the ridge.

• subduction

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS2-3

At location B, the crust is _______ dense.

• less

• more

At location A, the crust is...

• colder

• hotter

Tags

NGSS.MS-PS1-4

The pattern of magnetic stripes in rocks on either side of a mid-ocean ridge is the same.

• True

• False

Tags

NGSS.MS-ESS2-3

Who discovered sea floor spreading?

• Harry Hess

• Alfred Wegener

• Mr. Koob

• Mrs. Moody

Massive pieces of land that are part of the Earth's crust and upper mantle

• Tectonic plates

• Trenches

• Divergent boundary

• Continental shelves

Tags

NGSS.MS-ESS2-1

The deepest part of the ocean; long, narrow ditches

• Tectonic plates

• Trenches

• Divergent boundary

• Continental shelves

Which features form the longest mountain ranges on Earth?

• The mid-ocean ridges

• The deep-ocean trenches

• The Rockies

• The Andes

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS2-3