Earths Magnetic Field Rocks On Ocean Floor

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Earths magnetic field rocks on ocean floor.

This similar to how iron filing line up when they are next to a magnet as seen in the pictures below. Magnetometers are devices that can detect tiny deviations in the earth s magnetic field. These patterns were unlike any seen for continental 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. Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. 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. These instruments have been used to map the ocean floor.

This rock has strong magnetic properties that allow us to see the history of earth s magnetic field. The evidence exists in the extrusive igneous rock basalt on the ocean floor near the mid oceanic ridges. 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. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.

On either side the rocks are older the farther they are from the ridge. Over time the earth s magnetic field reverses its north. Magnetic striping magnetic minerals are found in rocks. When the rocks are in melted form these minerals will line up with earth s magnetic field.

The magnetic orientation of the earth is recorded in the igneous rock at the time of its. Thus these grains are permanent records of the location of the earth s magnetic field at the time the rock forms. The ground of the ocean is made of magnetite that is part of iron rich volcanic rock. Among the new findings was the discovery of zebra stripe like magnetic patterns for the rocks of the ocean floor.