Scientists
have also determined that the Ice Ages was caused by Plate Tectonics as well.
The Ice Ages are long time periods where the temperature of the globe are
extremely low and therefore large sheets of ice are formed and cover the earth.
During Ice Ages there are warmer periods when the ice will melt, there are also
periods when the ice will return and cover the atmosphere. The last known Ice
Age occurred about 20,000 years ago but is said to still continue on today.
This period occur when the shifting of the continents cause the warmer water at
the equator to be blocked from reaching the poles causing large sheets of ice.
Scientists have learned about the Ice Ages from studying fossils and landforms.
(Maasch, 1997) They have discovered that the sediment found provided history of
the climate. Scientists do this type of research by driving large poles into
the ice or ocean floor as deep as 2 miles under. They then study the cores that
are collected and retrieve information regarding climates for the season as
well as by the year. This information provides detailed information regarding
the climate and is helpful in determining the approximation of the Ice Ages. It
was said that over 50 million years ago tropical conditions were spread over
the Earth which actually caused trees to grow in the Arctic and Antarctica. (Maasch,
1997) This period of time was called the Eocene. This action is most likely
caused by plate tectonics and the movements. This cycle has be coined the
phrase of Wilson cycles. During the Wilson Cycles continents collide and pull
apart, oceans open and close, and mountains are formed and destructed. (Maasch,
1997) Because of these changes in formation the climate experiences cooler
temperatures. This, of course, is just one theory.