ICE AGEs
Ice
ages are periods in the earth’s history, when sea ice or glaciers have covered
a significant portion of the planets surface and significant cooling of the
atmosphere has occurred. Earth has existed for about 4.5 billion years
precisely, of which during this time it has experienced several ice ages, each
lasting tens of millions of years.
The
most recent ice age, the Pleistocene Epoch lasted from about 1.6 million years
to 10,000 years before present. The past 10,000 years have been part of a
relatively warm Inter-glacial period. However the presence of massive
continental ice sheets on Green lands and Antarctica, along with numerous
smaller glaciers in mountanious regions throughout the world, indicates that
earth is still in the grip of an ice age.
During
ice ages, several geologic changes occur. Water freezes and settles within the
growing glaciers, these processes cause the worldwide sea level to drop to as
much as 150m (500 ft) below the current sea level. When this process occurs, shallow
ocean waters that cover the continental shelves, or the edge of the continents,
recedes and uncovers the submerged lands.
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