Continental
Drift is the idea that the continents were all once connected; also known as
Pangaea, and then moved apart. A meteorologist named Alfred Wegner became obsessed with the
fact that it looked like all the continents combined. He came up with four
evidences that helped prove that the continents were once connected.
The first evidence was that South America and Africa really
looked like they were once connected. He wasn’t the first person to notice this
but he was the one who put more research into it.
The next evidence took more research to find. He found
that fossils of Mesosaurus were found in South America and in Africa.
Mesosaurus was a fresh water dinosaur that would not to be able survived the
trip from Africa to South America.
The third evidence is the fossil fuels found in
Antarctica. The have found coal in Antarctica and coal is made from compacted
plants and if there were plants there then at one time it was somewhere else on
the Earth.
The fourth and final evidence is the rock structures in
North America and Europe. The types of mountains are about the same age and
also the same type of rock.
Now Seafloor Spreading is our other main topic. Seafloor
Spreading is when magma comes out of the ridges in the ocean floor and makes
more ocean floor. However the earth is not getting bigger because there are
spots in the ocean where earth is going underneath another.
The first evidence of seafloor spreading is ageing. Ageing
is when they brought up different rocks of the mid Atlantic ridge and aged
them. They soon discovered that the farther away from ridge the older the rocks
are. Which means that magma comes up and cools then forms rock and pushes the
older rock farther away.
The last evidence is magnetic particles. Magnetic
particles are found in the rock in the mid Atlantic ridges and they then point
to the magnetic field. However they did find really old rocks that pointed to
the south that show that the magnetic field had reversed. Very good!
No comments:
Post a Comment