Dinosaurs Magazine: The death of a dynasty.
THIS theory came about from evidence found at the Hell Creek Formation in the western United States. Crystals of shocked quartz from the rare element iridium, have been found which show a meteor did land on earth. A large crater in the Gulf of Mexico and a layer of iridium found across the world suggest an asteroid up to 6 miles wide hit earth. Debris would have covered the planet blocking out the sun. So far, scientists have failed to conclude whether a meteor was responsible as they can only pinpoint fossil-finds to the near-est half a million years.
FOR hundreds of thousands of years before and after the asteroid, the movement of India against the Asian continental plate would have produced massive, prolonged volcanic activity.
Now known as the Deccan Traps, this activity generated enough basalt to cover an area the size of Alaska and Texas put together - with lava almost half a mile deep.
This phenomenon could have caused global cooling and ejected poisons into the atmosphere such as selenium, which is particularly toxic for developing embryos in eggs.
OTHER palaeontologists have looked for clues in the changing climate of the time.
Before the dinosaurs died out, subtle environmental changes were beginning to occur, including a drop in temperature and alterations in the sea currents.
These modifications to nature inevitably brought about changes in the planet's creatures, leading to the extinction of certain prehistoric beasts such as the ichthyosaurs and pliosaurs. Other marine creatures such as sea lizards, clams and squid-like belemnites also suffered, while on land numerous types of pterosaurs died out.
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|Publication:||The Mirror (London, England)|
|Date:||Feb 26, 2000|
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