Magnetic Stripes On The Sea Floor Are Created Where

These patterns were unlike any seen for continental rocks.

Magnetic stripes on the sea floor are created where.

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. The patterns reflect the creation and spreading of oceanic crust along the mid oceanic ridges. 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.

Magnetic reversals found in the sea floor do not cause continental drift. Plate tectonics and reversals of the earth s magnetic field are responsible for the magnetic stripes found on the ocean floor. 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. Basalt the once molten rock that makes up most new oceanic crust is a fairly magnetic substance and scientists began using magnetometers to measure the magnetism of the ocean floor in the 1950s.

These surveys revealed a series of invisible magnetic stripes of normal and reversed polarity in the sea floor like that shown in the figure below. Basalt forming at the ridge crest picks up the existing magnetic polarity.