Friday, June 19, 2009

The continental drift theory is the theory that once all the continents were joined in a super-continent, which scientists call Pangaea. Over a vast period of time, the continents drifted apart to their current locations. Alfred Wegener first supported continental drift.

Wegener’s explanation of continental drift in 1912 was that drifting occurred because of the earth’s rotation. This explanation and his theory were not widely accepted. Prior to Wegener, however, many had noted that the shapes of the continents seem to fit together, suggesting some schism in the past.

Continental drift was really not allowable as even an accepted theory until the 1950s. Most geologists accepted the theory as quite possible before 1970. Several factors point to the acceptance of the continental drift theory.

Fossil records from separate continents, particularly on the outskirts of continents show the same species. As well mineral specimens along the supposed break lines of the continents are nearly identical. Some identical species exist on certain continents, like an earthworm common to both Africa and South America suggesting the species could not have spontaneously arisen on both continents without some variations.

Continental drift theory also gained in popularity because of the theory of plate tectonics. Briefly plate tectonics suggests that the ocean floor began to spread and that the continents existed on “plates” that moved in response to the changing ocean floor. Disruption in the continents, such as earthquakes, is in response to the moving plates, suggesting that certain points of the continents are fairly constantly exhibiting tiny movements.

For example Point Reyes, in Northern California, located on the San Andreas Fault line, has been measured as slowly moving north at a rate of about half an inch per year. In fact, geologists theorize that with continued movement, Point Reyes might eventually become an island.

Not everyone accepts continental drift theory since not everyone accepts the same age for the earth. It is especially common among certain religions that endorse creationism to believe that the earth is far younger than supposed by geologists. Some of these religions also do not accept carbon dating as a way of determining earth, or fossil records being as old as scientists claim.

Most scientists, and those not believing in creationism, accept the continental drift theory, along with the theory of plate tectonics. Those endorsing the theory of intelligent design usually accept continental drift as well, but assert that a spiritual presence designed and created the earth. Continental drift theory is now taught as accepted theory in public schools throughout the US.

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