Magnetic Field Ocean Floor

This rock has strong magnetic properties that allow us to see the history of earth s magnetic field.

Magnetic field ocean floor.

Magnetometers are devices that can detect tiny deviations in the earth s magnetic field. These instruments have been used to map the ocean floor. The ground of the ocean is made of magnetite that is part of iron rich volcanic rock. The strips on the atlantic ocean floor in particular all seemed parallel to the mid atlantic ridge that is a volcanic ridge running roughly north to south with some zigs and zags halfway between europe africa and america.

In sediments the orientation of magnetic particles acquires a slight bias towards the magnetic field as they are deposited on an ocean floor or lake bottom. When the earth s magnetic field reverses a new stripe with the new polarity begins. They record the strength of the magnetic field in rocks on the ocean floor. Magnetic striping magnetic minerals are found in rocks.

This is called detrital remanent magnetization. This tool can detect small changes in magnetic fields. In the ocean floor the magnetization was orderly arranged in long strips. When the rocks are in melted form these minerals will line up with earth s magnetic field.

Thermoremanent magnetization is the main source of the magnetic anomalies around mid ocean ridges. Isotopic analysis of ocean core sediments help determine sea floor age and this can be used to infer past magnetism magnetic particles in basalt orient with the magnetic field in force at the curie point. 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. Ships tow these devices through the water.

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. The magnetic field that is produced by the oceans the molten core and rocks in the crust and upper mantle protects the planet from streams of charged particles known as the solar wind. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks. Such magnetic patterns led to recognition of the occurrence of sea floor spreading and they remain some of the strongest evidence for the theory of plate tectonics.

The figure below includes two images of the ocean floor. Seafloor spreading and magnetic striping rising magma assumes the polarity of earth s geomagnetic field before it solidifies into oceanic crust. 2 a magnetometer is a device scientists can now use to study the ocean floor. Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.

The ocean floor is uniformly old preserving the earth s 4 6 billion history.