How does magnetic striping support the continental drift theory?

Answer 1

By outline matching though it's not the coastline that counts but the true continental outlines, traced more closely by the continental shelves. The present coast-lines of the world are geologically very young features from the sea-level rising consequent on the last glacial retreat. so that is how the

Answer 2

As it happens, the Earth's magnetic field changes strength and even reverses its direction from time to time. Nobody really knows why.

We know it happens, though, because when liquid magma cools and becomes solid rock, some of the minerals in the rock preserve a record of the direction and strength of the magnetic field at that time. This "recording" is called paleomagnetism. Because they can use radioactive dating to figure out how old the rocks are, scientists have used paleomagnetism to make a geomagnetic reversal time scale, showing how the Earth's magnetic field has changed direction over the past couple hundred million years or so.

In some places there are huge mountain ranges on the floor of the ocean. These "mid-ocean ridges" are volcanic. Along these ridges, such as the Mid-Atlantic Ridge, new rocks are solidifying out of liquid magma.

The paleomagnetism in the rocks as you move away from the mid-ocean ridge is a series of magnetic "stripes," normal, reversed, normal, reversed, and so on. The stripes correspond to the geomagnetic reversal time scale, so geophysicists know that the ocean floor crust is newest at the mid-ocean ridges and older the further away from them you get.

This could only happen if new crust is being formed at the mid-ocean ridges and is moving away from them to either side. If this is happening, and if the oceanic crust attaches to continental crust without a break (as in many cases it does) then as the oceanic crust spreads the continents must move too, and that's "continental drift." Q.E.D. Geophysicists have also used paleomagnetism to chart the motion of continents more directly. They can use paleomagnetic data from continental rocks to get the distance and direction to the Earth's magnetic poles from their sample sites at the moment the rocks there became solid. They've actually been able to make charts of how the magnetic north and south poles have wandered, with respect to the continents, over millions of years. Only the magnetic poles don't wander that far from the geographic poles. Therefore, if the distance and direction to the pole changed but the location of the pole didn't, it must have been the continent that moved. They can even tell when one continent broke into two, or when two joined to become one. The track of the apparent motion of the pole will be the same on both pieces of land when the two lands are attached, but when the two move differently the track of the pole you see on each will be different too.

Answer 3

Some types of rocks have a Magnetic North and a Magnetic South. This is established when a rock is formed. If the continents stayed still then the rocks would match up with the land. There are places where the North and South do not match up with the Earth. This supports the theory that landmasses moved and changed over time.

Answer 4

Chemistry

03.03 Plate Tectonics: Past, Present, and Future

All of this plate movement over time really mixes things up! If we look at how plates move and look back in time, we are able to come up with some predictions of how the Earth used to look. These predictions are called the theory of continental drift.

The Continental Drift Theory is now called Plate Tectonic Theory. The Plate Tectonic Theory states that all of the continents of the Earth were once one big landmass. This landmass is named Pangaea. This continental movement is illustrated in the activity below. Click on the arrow when you are ready to begin.

There are several reasons why scientists believe the Continental Drift Theory is true. Fossils, as mentioned on the first page of this lesson, are one reason scientists believe this theory is true. Let's take a look at fossils and some other reasons that support the Continental Drift Theory. Roll over the images below for more information.Answers.com

The Petoskey Stone is just one example of how landmasses were different many years ago. If Michigan, or more specifically, the Continent of North America, was joined with the other continents and was located centrally, then there could have been shallow warm waters in Michigan. This explains why there are fossilized corals found in Northern Michigan.

We can also compare other fossils from different lands and find that there are many fossils that are the same, but are currently separated by oceans. For example, similar fossils have been found of plants and animals located in South America and Africa. These continents are separated by the Atlantic Ocean. It would have been physically impossible for these plants and animals to travel across the Atlantic Ocean.

Scientists have even found fossils of tropical plants in coal deposits in Antarctica! All of these examples support the idea that these landmasses were once connected.

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Magnetism

Some types of rocks have a Magnetic North and a Magnetic South. This magnetic orientation is established when the rock is formed. If the landmasses or continents of the Earth had remained fixed in the same place for all time, the Magnetic North and South of all rocks would exactly match that of the Earth. This is not true. There are several locations that the Magnetic North and South of rocks does not match that of the Earth. This fact supports the idea that the landmasses have moved and changed over time.

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Size and Shape Relationships

If you take a map and cut out all the continents, you see that they fit together almost perfectly, like a giant puzzle. Is this a coincidence? Scientists think not. This fact supports the idea that all of the continents were once connected in one giant landmass.

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Geology

Geologists study rocks and have found that the types and ages of rocks at the edges of certain continents are the same. There are also places where the size and shape match. For example, the rocks, shapes and types, of Africa and South America match. This fact supports the idea that all the continents were once connected in one giant landmass.

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Answer 5

Vine and Matthews discovered that there was symmetrical of magnetic stripes in the mid ocean ridges. In 1963 they published their idea and called it ‘Magnetic anomalies over oceanic ridges’.

That the symmetrical patterns showed that the earth's magnetic field switches directions over time, Hess was right! When magma rises from the mantle and cools it preserves a record of the earth polarity. This happens because the magnetite in basalt is so magnetic.

Magnetic stripping occurs when the oceanic plates pull away from each other, magma rises to the surface at the mid ocean ridges. This creates a new stripe of oceanic crust. Later when the Earth’s magnetic field flips again the new stripe aligns polarity in the opposite direction.

Magnetic stripes help to support the seafloor spreading theory because the magnetic stripes are parallel to the mid-ocean ridge and each stripe represents crust that formed and magnetized the ocean ridges during the time the polarity was either regular or irregular.

Magnetic striping supports Wegner's theory of continental drift because magnetic stripes prove that the crust is always moving. Telling us that it is possible that, at a time, all the continents were one.

Answer 6

The alternating bands of magnetism on either side of a mid ocean ridge are symmetrical to the alternating bands of magnetism on the other side of a mid ocean ridge.

Answer 7

yes