Wegener's Theory example essay topic

Pangaea: The Truth Untold "Scientists still do not appear to understand sufficiently that all earth sciences must contribute evidence toward unveiling the state of our planet in earlier times, and that the truth of the matter can only be reached by looking through all this evidence... It is only by combing the information furnished by all the earth sciences that we can hope to determine 'truth' here, that is to say, to find the picture that sets out all the known facts in the best arrangement and that therefore has the highest degree of probability. Further, we have to be prepared always for the possibility that each new discovery, no matter what science furnishes it, may modify the conclusions we draw" (Wegener, Alfred, The Origins of Continents and Oceans 4th edition). Some truly revolutionary scientific theories may take years or decades to win general acceptance among scientists. This is certainly true of plate tectonics, one of the most important and far-ranging geological theories of all time; when first proposed, it was ridiculed, but steadily accumulating evidence finally prompted its acceptance, with immense consequences for geology, geophysics, oceanography, and paleontology. And the man who first proposed this theory was a brilliant interdisciplinary scientist, Alfred Wegener.

Page 2 The theory of Pangea started when early scientists noticed the similarities between South America and Africa. Although many scientists were skeptical some dug deeper into finding the evidence. It was actually an accident how the first break in the search for the truth. Wegener was browsing in the university library when he came across a scientific paper that listed fossils of identical plants and animals found on opposite sides of the Atlantic. Intrigued by this information, Wegener began to look for, and find, more cases of similar organisms separated by great oceans. He began to take missions to Africa and South America in order to find similarities about their crust.

Science at the time explained such cases by assuming that land bridges, now sunken, had once connected the separated Continents. They began studying different plants and animals on different continents that could have once been connected. But Scientists saw the close fit between the coastlines of Africa and South America. Might the similarities among organisms be due, not to land bridges, but to the continents having been joined together at one time? As he later wrote: "A conviction of the fundamental soundness of the idea took root in my mind".

(Wegener, Alfred, The Origins of Continents and Oceans 3rd Edition, 167). Such an insight, to be accepted, would require large amounts of supporting evidence. Scientists found that large-scale geological features on separated continents often matched very closely when the continents were Page 3 brought together. A famous Geologist at the time Emile Argrand became intrigued by Wegener's theory and he began to study the Appalachian and Scottish Highlands For example, the Appalachian mountains of eastern North America matched with the Scottish Highlands, and the rock formation of the Karroo system of South Africa were identical to those of the Santa Catarina system in Brazil. Wegener also found that the fossils found in a certain place often indicated a climate utterly different from the climate of today: for example, fossils of tropical plants, such as ferns and cycads, are found today on the Arctic island of Spitsbergen. All of these facts supported Wegener's theory of "Continental Drift In 1915.

The first edition of The Origin of Continents and Oceans, a book outlining Wegener's theory, was published; expanded editions were published in 1920, 1922, and 1929. About 300 million years ago, claimed Wegener, the continents had formed a single mass, called Pangaea, which means all of earth in Greek. Pangaea had drifted, or split, and its pieces had been moving away from each other ever since. Wegener was not the first to suggest that the continents had once been connected, but he was the first to present extensive evidence from several fields. Reaction to Wegener's theory was almost hostile, and often harsh with very inappropriate behavior.

Dr. Rollin T. Chamberlin of the University of Chicago said, "Wegener's hypothesis in general is of the footloose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories". (Scharzbach, Page 4 114). Part of the problem was that Scientists had no convincing mechanism for how the continents might move. Early thought that the continents were moving through the earth's crust, like icebreakers plowing through ice sheets, and that tidal-force were responsible for moving the continents.

Opponents of continental drift noted that plowing through oceanic crust would destroy continents beyond recognition, and that tidal-forces were far too weak to move continents; one scientist calculated that a tidal-force strong enough to move continents would cause the Earth to stop rotating in less than one year. Another problem was that flaws in Wegener's original data caused him to make some incorrect and outlandish predictions: he suggested that North America and Europe were moving apart at over 250 cm per year; this is about ten times the fastest rates seen today, and about a hundred times faster than the measured rate for North America and Europe. There were scientists who supported Wegener: the South African geologist Alexander Du Toit supported it as an explanation for the close similarity of strata and fossils between Africa and South America, and the Swiss geologist 'Emile Argrand saw continental collisions as the best explanation for the folded and buckled strata that he observed in the Swiss Alps. Wegener's theory found more scattered support after his death, but the majority of geologists continued to believe in static continents and land bridges. Page 5 What prompted the revival of continental drift?

In large part it was increased exploration of the Earth's crust, notably the ocean floor, beginning in the 1950's and continuing on to the present day. By the late 1960's, plate tectonics were well supported and accepted by almost all geologists. Scientists now know that Wegener's theory was wrong in one major point: continents do not plow through the ocean floor. Instead, both continents and ocean floor form solid plates, which "float" on the asthenosphere, the underlying rock that is under such tremendous heat and pressure that it behaves as an extremely viscous liquid. Since Wegener's day, scientists have mapped and explored the great system of oceanic ridges, the sites of frequent earthquakes, where molten rock rises from below the crust and hardens into new crust. Scientists now know that the farther away a person travels from a ridge, the older the crust is, and the older the sediments on top of the crust are.

The clear implication is that the ridges are the sites where plates are moving. Where plates collide, great mountain ranges may be pushed up, such as the Himalayas; or if one plate sinks below another, deep oceanic trenches and chains of volcanoes are formed. Earthquakes are by far most common along plate boundaries and rift zones: plotting the location of earthquakes allows seismologists to map plate boundaries and depths. Paleo magnetic data have allowed scientists to map past plate Page 6 movements much more precisely than before. It is even possible to measure the speed of continental plates extremely accurately, using satellite technology. There are still many scientist say that Wegener, Argrand, and Du Tion were all failures because they introduced an ideas that were considered bizarre in there day.

Nevertheless, These Scientists basic insights remain unknown, and the lines of evidence that he used to support there theories are still actively being researched and expanded. In conclusion, the theory of Pangea was never really proven. Although Wegener, Du Toit, and Argrand have come extremely close to the truth, their research was not well enough to prove that the super-continent really existed. The way he predicted the movement patterns was incorrect by a long shot.

Pangaea has still been proven to just be a mere legend but maybe in the near future it may be proven correct". I believe the common world will change when this information is revealed" (Wegener, 26).