Pages 44-46. Notes.

-Anyone who has ever used a compass before had found out the Earth;s magnetic field has a north and south pole.
-Earth's magnetic field is similar to the bar of magnet. Invisible lines of force pass through the planet and extend from one magnetic pole to another.
-As for the earth's gravity, we cannot feel the earth's magnetic field.
-When heated above a temperature known as the Curie point, these magnetic minerals lose their magnetism.
-Rocks that had formed thousands of years ago and have a record of the magnetic field, they were said to process fossil magnetism, or in other words paleomagnetism.
-Magnetism doesn't only direct north or south poles like a compass, but it also provides a means of the latitude of their origin.
-A study of rock magnetism was conducted during the 1950's in Europe by Runcorn and his associates that led to this interesting discovery.
-Over the next few decades a much better picture of larges expanses of the seafloor began to slowly emerge.
-From all that work came the discovery of a global oceanic ridge that goes through all of the major oceans in a manner similar to the seams on a baseball.
-In the early 1960's a discovery of a newly hypothesis that was later names seafloor spreading.
-Ocean ridges were proposed that oceanic ridges are located above in the mantle.



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The Pangaea theory is one that states that all present continents were once together and collectively known as a 'supercontinent' called a Pangaea. Defining the way the continents were 200 millions years ago before it split up. 1.jpg
Mesosaurus was one of the first reptiles to return to the water in which its amphibian ancestors originally lived.

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Is the largest and best-known genus of the extinct order of seen ferns.
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After the split of the pangaea, it has created different continents and made a huge gap of water in between North America/South America, and Africa where the it had split up.



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The rigid layer is known as the Lithosphere, which is broken into pieces called the plates. Lithosphere plates are thinnest in the oceans where their thickness may vary from as little as a few kilometers at the oceanic ridges.

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Lithosphere and tectonic plates move together with respect, and and often changing in shape and size.

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Where two plates move apart that creates new seafloor.

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Where two plates move together. The lithosphere descends beneath an overriding plate to create a mountain system.

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Where two plates grind past each other without destruction of lithosphere.