Ocean Floor Magnetic Stripes

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

Ocean floor magnetic stripes. It became known as the vine matthews morley hypothesis recognising the work of canadian geologist lawrence morley who had independently come up with the same idea. Magnetic stripes in the 20th century the magnetic survey was conducted in the mid ocean ridge in order to investigate evidence of sea floor spreading. What could cause this. These two things were the magnetic striping on the ocean floor and the age of seafloor rocks.

Magnetic stripes and isotopic clocks oceanographic exploration in the 1950s led to a much better understanding of the ocean floor. The specific magnetism of basalt rock is determined by the earth s magnetic field when the magma is cooling. In the 1960s the past record of geomagnetic reversals of earth s magnetic field was noticed by observing magnetic stripe anomalies on the ocean floor. Note that the stripes are symmetrical about the central dusky purple stripe.

Magnetic striping of the sea floor after mid ocean ridges and trenches were discovered more evidence was discovered that helped to support the theory that the continents had moved around. Basalt forming at the ridge crest picks up the existing magnetic polarity. The patterns reflect the creation and spreading of oceanic crust along the mid oceanic ridges. What they discovered was that the magnetism of the ocean floor around mid ocean ridges was divided into matching stripes on either side of the ridge.

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. 9 10 this results in broadly evident stripes from which the past magnetic field polarity can be inferred from data gathered with a magnetometer towed on the sea surface or from an aircraft. In the oceans magnetic stripes are symmetrical about a mid ocean ridge axis. Magnetic stripes on the ocean floor image courtesy of the naked science society they published the idea in 1963 in a nature paper called magnetic anomalies over oceanic ridges.

Magnetic striping magnetic minerals are found in rocks. These patterns of stripes provide the history of seafloor spreading. Among the new findings was the discovery of zebra stripe like magnetic patterns for the rocks of the ocean floor. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid ocean ridges.

At the mid ocean ridge spreading axis these flips in the direction of the earth s magnetic field are recorded in the magnetization of the lava.