Magnetic Stripping

1. Magnetic striping

a) normal and reversed polarity

b) stripes of rock on the seafloor with alternating magnetic properties

2. Evidence from rock composition

a) basalt is a volcanic rock that forms the oceanic crust

b) contains minerals that can be influenced by Earth’s magnetic field

3. Evidence from rock patterns

a) alternating polarity forms a striped pattern

b) not random or isolated occurrences

https://pubs.usgs.gov/gip/dynamic/stripes.html

• The plate tectonic theory is supported by the alternating polarity of the seafloor, which corresponds with the regular reversal of Earth's magnetic field.

• Lava which is high in iron level contain magnetic materials which accumulate at the oceanic-oceanic divergent plate boundaries.

• The magnetic materials line up in the direction of the Earth's magnetic north as they solidify.

• As the seafloor spreads, bands of rock of different ages form a symmetrical pattern of normal and reversed polarity on both sides of the oceanic ridge.