1.3 Magnetic Striping

What is magnetic stripping?

• The removal of rocks from the ocean floor

• The pattern of magnetic minerals aligned in rocks on either side of mid-ocean ridges

• The movement of tectonic plates beneath the lithosphere

• The melting of oceanic crust

What causes magnetic stripes on the ocean floor?

• Wind erosion

• Plate subduction

• Changes in Earth’s magnetic field

• Evaporation of seawater

How do magnetic minerals in rocks record Earth's magnetic field?

• They align to the Sun’s rays

• They align to Earth’s magnetic field when the rock cools

• They only align in subduction zones

• They never align with anything

Magnetic stripes are symmetrical on both sides of a mid-ocean ridge because:

• Seafloor spreading occurs equally in both directions

• Earth's crust is perfectly flat

• There is no volcanic activity at the ridge

• Only one side records the magnetic field

The magnetic stripes on the ocean floor are evidence for:

• Plate subduction

• Seafloor spreading

• Earthquake formation

• Mountain building

When did scientists first notice magnetic stripping patterns?

• During space exploration

• After the discovery of fossil fuels

• While mapping the ocean floor

• When studying mountain ranges

Which landform is associated with magnetic stripping?

• Fold mountains

• Ocean trenches

• Mid-ocean ridges

• Rift valleys

Explain why the pattern of magnetic stripes supports the theory of seafloor spreading.

• They show symmetrical patterns on both sides of the ridge

• They form only near volcanoes

• They are made of fossils

• They occur only in the Atlantic Ocean

Why is magnetic stripping considered strong evidence for plate tectonics?

• It proves the existence of magma

• It shows continents move back and forth

• It demonstrates new crust is formed and spreads from ridges

• It explains why the continents are warm

What does alternating magnetic polarity in oceanic rocks suggest?

• Continents are fixed in place

• Earth’s magnetic field has never changed

• Earth’s magnetic field reverses over time

• Volcanoes do not erupt underwater