Dinosaur Extinction Theories
A look into the many theories and speculation about the extinction of the dinosaur.
When one starts looking into the riddle of the disappearance of the dinosaur, one thing becomes immediately apparent: Paleantology û the study of fossils -is a highly opinionated and speculative science. The number of theories as to the disappearance of the dinosaur is limited only by the number of æexpertsÆ who care to voice their opinions. Here are some of the reasons given for the disappearance of the dinosaur:
(1) deterioration in the climate
(2) lack of food
(3) disease and parasites
(4) changes in the pressure and composition of the atmosphere
(6) Continental Drift
(7) Poison gases
(8) Volcanic ash
One belief which has gained substantial credence in recent times is the Sudden Extinction Theory, put forth by father and son team of Luis and Walter Alvarez. The Alvarezs based their theory around a thin red layer of clay which they found sandwiched between two limestone layers in a rock formation in Italy. The lower layer of limestone contained many fossils, but the top one contained virtually none. The conclusion was that life had suddenly disappeared and that the thin red layer of clay was instrumental in solving the puzzle.
When the clay was analysed it was found to be rich in iridium, containing 30 times more than would have been expected. Such high sources of iridium can come from only one of two sources û the earthÆs core or from beyond the earth. Their conclusion was that the source of this iridium was a huge asteroid that had plummeted to earth, causing the sudden extinction of the dinosaur.
This theory fits in with the evidence which shows a dramatic, sudden removal of the dinosaur from the fossil record. This would not be the case with many of the theories already proposed. Neither does the fossil record support the view that the dinosaur evolved into another species. There is no intermediary fossil evidence to support such an evolutionary step.
Is the Asteroid theory the truth. Perhaps, we will never know. It is relatively certain, however, that the dinosaur vanished in some variation of a sudden extinction theory and the asteroid theory has as much, if not more evidence to support it as any at this time.
The dinosaur is a thing of the past but, thanks, to the technology of the movie makers we can still experience what it must have been like to get up close and personal with these creatures. And we can do so from the comfort and safety of a movie theatre. What more could we want?