Plate Tectonics
Plate Tectonics Since the beginning of human kind there has been a cloud of
wonder regarding the origin of our planet. Scientist interested in this field
through out the years have developed many different theories to how our planet
came about. Before the Twentieth Century, scientist and geologist alike revolved
in the idea that Mountain building was due to the massive contractions of the
earth caused by the gradual cooling of molten rocks. In 1900, American scientist
Joseph Le Conte, published an article in the Appleton’s Popular Scientific
Monthly. He described that the problem in understanding mountain building was
establishing the cause of sideways pressure. “The most obvious and as yet the
most probable view is that it is the result of the secular contraction of the
earth which has gone on throughout the whole history and is still going on.” (2)
It was not until 1910, that an American Geologist named F.B.Taylor, proposed the
idea of a continental drift. His scientific peers dismissed Taylor’s idea,
because there was just not enough proof. However, Taylor’s idea was then
resurfaced by a German scientist named Alfred Wegener. He proposed that the
continents surrounding the Atlantic Ocean, Africa and South America fit together
like a jigsaw puzzle. Wegener was a balloonist, astronomer, explorer,
meteorologist, while in his spare time he researched paleontology, geophysics
and geology. His broad range of studies enabled him to incorporate his theory of
Plate Tectonics. Wegener, later in 1915 while in sick leave from the German
military published his idea that interpreted how his continental drift theory
worked.
He proposed that a huge landamass called Pangea, meaning (all land”)
existed 200 million years ago. He furthered explained that this super continent
began to drift apart very slowly throughout millions of years into what it looks
like now. Wegener went on several expeditions through out his life to the
continents of South America and Africa. He came back with evidence to support
his claim of plate tectonics. Wegener and his expedition brought back rock
structures, fossils, and evidence of ancient climates. When it came to rock
structures, Wegener looked for the similarities of the rocks found along
coastlines and the mountain belts found on the continents. They looked at the
mountain belts of the Appalachian Mountains and the Caledonian Mountains in
Scandinavia and the British Isles. These two continuos belts contained similar
rock structures and the ages of these rocks matched the on both ends of the
African and South American continents. Wegener also found evidence of massive
climatic changes. He researched and found out that ancient glacial deposits were
found indicating that ice sheets covered a large part of the Southern
Hemisphere, India and Australia. Wegener's explanation of the glaciation was
that the ”landmasses where all fitted together as a super continent with South
Africa centered over the South Pole.” (1.) Pag. 474) He furthered explained that
the Northern Hemisphere was near the equator supporting the idea of coal
deposits being located there. Wegener was more intrigued of the fact that
fossilized remains were being found along South America and Africa. Remains of
the aquatic prehistoric dinosaur called Mesosaurus were only found in eastern
South America and Africa.
