Ice Age was those early periods of the earth's history when large areas of the globe were covered by glaciers and ice sheets.
During the earth's long history, there have been several ice ages.
The first ice age took place during Precambrian times, about 700 million years back.
Another ice periods occurred during the late Carboniferous and early Permian periods, about 280 million years back.
And a third, known as the Pleistocene Ice Age began only two million years ago and is probably still going on.
Here we shall discuss about the Pleistocene Ice Age only because the information about the first two ice periods is not available.
Pleistocene Ice Age consisted of four periods.
During each period the ice formed and advanced southward, then melted back towards the North Pole.
This happened four times.
The cold periods are called 'glacial ages' and the warm ones (when the ice retreated) are known as 'interglacial' periods.
The first period of ice came two million years back and is known as Nebraskan.
The second period came about 12, 50,000 years ago.
It is called the Kansan.
The third one came about 500,000 years back.
It is called the Illionoian period.
The fourth period known as Wisconsin period came about 100,000 years back.
In between these glacial periods, there have been three interglacial ages.
These interglacial ages are called the Aftonian, the Yarmouth and the Sangamon ages.
A typical glacial age lasts about 40,000 to 60,000 years and interglacial age lasts about 40,000 years.
Ice of Wisconsin period began to melt about 40,000 years back and ended some 10,000 years ago according to geologists the earth at present many be in an interglacial age.
Scientists have learned a lot about ice periods by studying fossils.
Geologists believe that the great ice sheets were centered near Hudson Bay in North America and on the Scandinavian Peninsula in Europe.
The ice became thick and flowed out from these centres.
All of Canada and one-third of northern United States, as far south as New York City and the Missouri River valley, were covered by ice.
In places the ice thickness was from 2400 to 3000 m.
In Europe ice covered all of the northern Europe, the British Isles, and much of northern Russia.
During Pleistocene epoch, more than 30% of the earth's surface was covered with ice.
During this age plants and animals were forced to live in more restricted environments.
Many lakes, including the Great lakes, were formed during the last ice periods.
During the earth's long history, there have been several ice ages.
The first ice age took place during Precambrian times, about 700 million years back.
Another ice periods occurred during the late Carboniferous and early Permian periods, about 280 million years back.
And a third, known as the Pleistocene Ice Age began only two million years ago and is probably still going on.
Here we shall discuss about the Pleistocene Ice Age only because the information about the first two ice periods is not available.
Pleistocene Ice Age consisted of four periods.
During each period the ice formed and advanced southward, then melted back towards the North Pole.
This happened four times.
The cold periods are called 'glacial ages' and the warm ones (when the ice retreated) are known as 'interglacial' periods.
The first period of ice came two million years back and is known as Nebraskan.
The second period came about 12, 50,000 years ago.
It is called the Kansan.
The third one came about 500,000 years back.
It is called the Illionoian period.
The fourth period known as Wisconsin period came about 100,000 years back.
In between these glacial periods, there have been three interglacial ages.
These interglacial ages are called the Aftonian, the Yarmouth and the Sangamon ages.
A typical glacial age lasts about 40,000 to 60,000 years and interglacial age lasts about 40,000 years.
Ice of Wisconsin period began to melt about 40,000 years back and ended some 10,000 years ago according to geologists the earth at present many be in an interglacial age.
Scientists have learned a lot about ice periods by studying fossils.
Geologists believe that the great ice sheets were centered near Hudson Bay in North America and on the Scandinavian Peninsula in Europe.
The ice became thick and flowed out from these centres.
All of Canada and one-third of northern United States, as far south as New York City and the Missouri River valley, were covered by ice.
In places the ice thickness was from 2400 to 3000 m.
In Europe ice covered all of the northern Europe, the British Isles, and much of northern Russia.
During Pleistocene epoch, more than 30% of the earth's surface was covered with ice.
During this age plants and animals were forced to live in more restricted environments.
Many lakes, including the Great lakes, were formed during the last ice periods.
SHARE
