Monday, January 19, 2015

Continental Drift/Seafloor Spreading

Continental Drift is the theory that all continents were all connected together at one point of time, but then slowly moved to their current location. There are four facts to prove this.

1. Fossils - The fossil of a mesosaurus is found half on one continent and half on another continent. There is no way he flew across because he was a reptile. He couldn't of swam the way because he could only swim in fresh water, while the ocean is salt water.

2. Striation Marks - Glacial striation marks are found in unlikely climates, which in current days would be impossible for a glacier to be found there. This must mean that the continent must of been in a warmer climate in past time.

3. They Fit Together - They just look like fit together.

4. Mountains - A set of mountains are found in one place, and across the ocean they are mountains that are made of the EXACT same rock of the first set of mountains, which is near impossible.

Seafloor Spreading the the spreading of the Seafloor.

1. When scientists studied patterns in the rocks of the ocean floor, they found more support for sea-floor spreading. You read earlier that Earth behaves like a giant magnet, with a north pole and a south pole. Surprisingly, Earth’s magnetic poles have reversed themselves many times during Earth’s history. The last reversal happened 780,000 years ago. If the magnetic poles suddenly reversed themselves today, you would find that your compass needle points south. Excellent!

2. Samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge. How did they find this out? 


Picture for sea floor spreading? 



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