Earths Magnetic Field Rocks On Ocean Floor

Thus these grains are permanent records of the location of the earth s magnetic field at the time the rock forms.

Earths magnetic field rocks on ocean floor.

Magnetic striping magnetic minerals are found in rocks. False the concept of seafloor spreading was supported by magnetic polarity stripes on 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 earth s magnetic field reverses in a regular pattern every few hundred thousand years.

The ground of the ocean is made of magnetite that is part of iron rich volcanic rock. Over time the earth s magnetic field reverses its north. These patterns were unlike any seen for continental rocks. This rock has strong magnetic properties that allow us to see the history of earth s magnetic field.

When geologists determined the ages of the rocks in the magnetic reversal bands on either side of mid ocean ridges they found that the rocks at the center of a mid ocean ridge are the youngest. The evidence exists in the extrusive igneous rock basalt on the ocean floor near the mid oceanic ridges. 174 unit 3 dynamic earth m agnetic north magnetic north bands of rocks on both. On either side the rocks are older the farther they are from the ridge.

These instruments have been used to map the ocean floor. When the rocks are in melted form these minerals will line up with earth s magnetic field. Magnetometers are devices that can detect tiny deviations in the earth s magnetic field. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.

Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor. The magnetic orientation of the earth is recorded in the igneous rock at the time of its. This similar to how iron filing line up when they are next to a magnet as seen in the pictures below. As new crust is created on the ocean floor the new crust solidifies with its iron oxide particles acting like miniature compass needles pointing to wherever magnetic north is at the time.