Sea Floor Spreading Magnetic Reversal Exercise

Magnetic reversals and sea floor striping a key factor in establishing the theory of plate tectonics was recognition of past reversals in the earth s magnetic field and the mapping of normal and reverse magnetic striping on the ocean floor.

Sea floor spreading magnetic reversal exercise.

The patterns reflect the creation and spreading of oceanic crust along the mid oceanic 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. The study of the earth s magnetic field as recorded in the rock record was an important key in reconstructing the history of plate motions. Map showing the age of the atlantic ocean seafloor in millions of years versus the distance from the mid ocean ridge age 0.

As magma cools particles in it get frozen in the direction of the. A polarity reversal means that the magnetic north flips to where we know the south pole is. Magnetic reversal proves seafloor spreading because we can see the polarity of the earth s magnetic field in rocks. Marine magnetic anomalies result from seafloor spreading in conjunction with choose one.

Imagnetic reversals exercise 3 2 seafloor spreading rates north america point a pa re o ھے وف س سیم africa ye point b figure 5. Basalt forming at the ridge crest picks up the existing magnetic polarity. The motion of the earth s molten outer core produces a magnetic field that is characterized by force lines emanating from near the. Seafloor spreading and polar reversal.

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. Apparent wander of the magnetic poles. The discovery of magnetic stripes in oceanic crust and how this supports wegener s theory of continental drift or as we now know it plate tectonics. This creates a symmetrical pattern of magnetic stripes of opposite polarity on either side of mid ocean ridges.

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.