Magnetic Reversals And Seafloor Spreading

The hypothesis links seafloor spreading and geomagnetic reversals in a powerful manner with each expanding knowledge of the other.

Magnetic reversals and seafloor spreading.

Enjoy the videos and music you love upload original content and share it all with friends family and the world on youtube. Early in the history of investigating the hypothesis only a short record of geomagnetic field reversals was available for studies of rocks on land. Magnetic stripes are the result of reversals of the earth s field and seafloor spreading. Figure 5 magnetic reversals in oceanic crust are shown as bands of light blue and dark blue oceanic crust.

This record of magnetic reversals was the final proof that seafloor spreading does occur. Its magnetization is in the direction of the local magnetic force at the time when it cools down. In 1963 both the geophysicist frederick j. As magma cools particles in it get frozen in the direction of the.

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. 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. Magnetic reversals after molten lava emerges from a volcano it solidifies to a rock. Magnetic reversal proves seafloor spreading because we can see the polarity of the earth s magnetic field in rocks.

New oceanic crust is magnetized as it forms and then it moves away from the ridge in both directions. Paleomagnetism or palaeomagnetism in the united kingdom is the study of the record 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. This was sufficient to allow computing of spreading rates over the last 700 000 years on many mid ocean.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. 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.