Earths Magnetic Field Rocks On Ocean Floor

The ground of the ocean is made of magnetite that is part of iron rich volcanic rock.

Earths magnetic field rocks on ocean floor.

When the rocks are in melted form these minerals will line up with earth s magnetic field. Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor. This similar to how iron filing line up when they are next to a magnet as seen in the pictures below.

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. Over time the earth s magnetic field reverses its north. 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.

The magnetic orientation of the earth is recorded in the igneous rock at the time of its. 174 unit 3 dynamic earth m agnetic north magnetic north bands of rocks on both. These patterns were unlike any seen for continental rocks. Magnetometers are devices that can detect tiny deviations in the earth s magnetic field.

Magnetic striping magnetic minerals are found in rocks. Thus these grains are permanent records of the location of the earth s magnetic field at the time the rock forms. 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. 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. The polarity of the earth s magnetic field is recorded in igneous rocks and reversals of the field are thus detectable as stripes centered on mid ocean ridges where the sea floor is spreading while the stability of the geomagnetic poles between reversals has allowed paleomagnetism to track the past motion of continents. 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.