Magnetic Reversals And Seafloor Spreading

Seafloor spreading and polar reversal.

Magnetic reversals and seafloor spreading.

Early in the history of investigating the hypothesis only a short record of geomagnetic field reversals was available for studies of rocks on land. The hypothesis links seafloor spreading and geomagnetic reversals in a powerful manner with each expanding knowledge of the other. Enjoy the videos and music you love upload original content and share it all with friends family and the world on youtube. Magnetic reversals after molten lava emerges from a volcano it solidifies to a rock.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Vine and the geologist lawrence w. Magnetic reversal proves seafloor spreading because we can see the polarity of the earth s magnetic field in rocks. What they discovered was the mid ocean ridge was actually a site where tectonic plates which are large pieces of the earth s crust were pulling apart from.

In most cases it is a black rock known as basalt which is faintly magnetic like iron emerging from a melt for which gilbert already noticed a similar process. This record of magnetic reversals was the final proof that seafloor spreading does occur. Morley independently realized that if the seafloor spreading theory was correct then the rocks surrounding mid oceanic ridges should show symmetric patterns of magnetization reversals recording the changes of the earth s magnetic field in the volcanic rocks at the. Magnetic stripes are the result of reversals of the earth s field and seafloor spreading.

Paleomagnetism or palaeomagnetism in the united kingdom is the study of the record of the. New oceanic crust is magnetized as it forms and then it moves away from the ridge in both directions. As magma cools particles in it get frozen in the direction of the. The models show a ridge a about 5 million years ago b about 2 to 3 million years ago and c in the present.

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 what they discovered was that the magnetism of the ocean floor around. Figure 5 magnetic reversals in oceanic crust are shown as bands of light blue and dark blue oceanic crust.