Dinosaurs: Their Lives, Their Deaths and Their Evolution!
by Dr. Bob Gardner
Department of Mathematics
Department of Physics and Astronomy
Institute of Mathematical and Physical Sciences
East Tennessee State University
The Mesozoic Era - When Dinosaurs Ruled!
First, let's discuss a little geology.
In 1912, Alfred Wegener
proposed that the continents of
the Earth move. He based this hypothesis on the fact that many of
the continental masses fit together like pieces of a jigsaw puzzle.
He also noticed a continuity of mountain ranges, geological deposits,
and the distribution of fossils between separate continents. However,
Wegener lacked one of the most important parts of a scientific
theory:
a mechanism to move the continents around. Therefore, the hypothesis of
continental drift, as it was called, was not initially accepted.
In the 1950's and `60's, surveys of the ocean floors showed mid-oceanic ridges
where new ocean floor is formed and as a result, the ocean floor spreads.
Trenches were also found where ocean floor is destroyed. Finally, the
mechanism which drives this conveyor belt of tectonic plates was discovered.
It is the result of convection currents in the mantle, the layer beneath the
Earth's crust. The currents themselves are results of molten rock bubbling
up as it is heated by the Earth's core. The idea of continental drift
deserves the title "theory" and today is called the theory of
plate tectonics.
There is a great deal of evidence supporting the theory and it is universally
accepted by the geological community. As a result of continental drift, the
appearance of the globe has changed dramatically through time.
300 million years ago all land masses were joined together in a supercontinent
called Pangaea. By the
start of the Triassic, Pangaea had begun to break up and over the past
200 million years, the continents assumed their present configuration.
