Magnetic Field Ocean Floor

Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor.

Magnetic field ocean floor. At spreading centres this crust is separated into parallel bands of rock by successive waves of emergent magma. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks. 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. 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.

Magnetic striping magnetic minerals are found in rocks. Ships tow these devices through the water. 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.

This similar to how iron filing line up when they are next to a magnet as seen in the pictures below. When the earth s magnetic field reverses a new stripe with the new polarity begins. These instruments have been used to map the ocean floor. This tool can detect small changes in magnetic fields.

The ground of the ocean is made of magnetite that is part of iron rich volcanic rock. 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. In the ocean floor the magnetization was orderly arranged in long strips. The survey data was used to create three dimensional relief maps of the ocean floor.

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. When the rocks are in melted form these minerals will line up with earth s magnetic field. This rock has strong magnetic properties that allow us to see the history of earth s magnetic field. They record the strength of the magnetic field in rocks on the ocean floor.

2 a magnetometer is a device scientists can now use to study 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. The ocean floor is uniformly old preserving the earth s 4 6 billion history. This is called detrital remanent magnetization.

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.