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Date: Prior to 1993


Question:
If the Earth formed out of the primordial gas cloud, one would expect that the continents would be dispersed in a balanced configuration as the Earth cooled. However modern theory places them together in a large land mass or "supercontinent," seemingly in an out of balanced state. How did this happen?



Replies:
Wonderful question! I am going to quote from two texts ["Pangaea" is the name given to the "supercontinent" which, it is believed, broke apart over 200 million years ago, into pieces which drifted apart and became the present-day continents]: From "The Solar System" by Encrenaz and Bibring, p. 135: "It is now possible to follow the history of the destruction of Pangaea and geological evolution that was a result. On the other hand, we have hardly any information about the continents that existed before that phase when there was just one: did Pangaea appear as a result of the incessant movement of the continents, shortly before the break-up, or had it existed as a stable entity for thousands of years? From what we know of the causes of continental drift, the first possibility seems more likely." From "Exploration of the Universe" by Abell, Morrison, and Wolff, pp.262-3: "If we extrapolate the plates' motion backward we arrive, some 200 million years ago, at the supercontinent of Pangaea... The configuration of the continents before Pangaea is less well understood. It is clear that plate tectonics were at work, from the existence of old mountains (such as the Urals in the U.S.S.R. and the Appalachians in the U.S.) that were formed more than 200 million years ago. Recent studies indicate that plate tectonic activity in what is now North America can be traced back 1.5 billion years." In other words, it is believed that Pangaea was not the original land-mass configuration, but there are no guesses about how it came to be.

Ronald Winther


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