Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.
What are magnetic stripes on the ocean floor.
Tape one end of each piece of audiotape to a flat surface.
Among the new findings was the discovery of zebra stripe like magnetic patterns for the rocks of the ocean floor.
When magma flows out of a mid ocean ridge small magnetic minerals in the magma align themselves to point in the direction of the earth s current magnetic north.
This results in broadly evident stripes from which the past magnetic field polarity can be inferred from data gathered with a magnetometer towed on the sea surface or from an aircraft.
Note that the stripes are symmetrical about the central dusky purple stripe.
These surveys revealed a series of invisible magnetic stripes of normal and reversed polarity in the sea floor like that shown in the figure below.
Evidence from magnetic stripes.
Magnetic stripes in the 20th century the magnetic survey was conducted in the mid ocean ridge in order to investigate evidence of sea floor spreading.
The specific magnetism of basalt rock is determined by the earth s magnetic field when the magma is cooling.
At the mid ocean ridge spreading axis these flips in the direction of the earth s magnetic field are recorded in the magnetization of the lava.
Oceanographic exploration in the 1950s led to a much better understanding of the ocean floor.
This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid ocean ridges.
These patterns of stripes provide the history of seafloor spreading.
Basalt forming at the ridge crest picks up the existing magnetic polarity.
This pattern of stripes could represent what scientists see on the seafloor.
Touch a bar magnet s north pole to the first piece of.
The pieces should be spaced 1 cm apart and lined up lengthwise in a single row.
When the rocks are in melted form these minerals will line up with earth s magnetic field.
In the oceans magnetic stripes are symmetrical about a mid ocean ridge axis.
Magnetic striping magnetic minerals are found in rocks.
Over time the earth s magnetic field reverses its north to south polarity and the magnetic minerals point in the opposite direction creating a striped pattern.
By using the magnetometer the magnetic polarity will be shown through a timescale that contains the normal and a reverse polarity.
The patterns reflect the creation and spreading of oceanic crust along the mid oceanic ridges.
What could cause this.
These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.
Obviously the ocean floor had a story to tell but what.
These patterns were unlike any seen for continental rocks.
What they discovered was that the magnetism of the ocean floor around mid ocean ridges was divided into matching stripes on either side of the ridge.