Three ice ages

The glacial period was the period when the Earth was very cold, the temperature suddenly fell low on a global scale, the ice covered the ground. In the history of the Earth that occurred three times in the past, it was the glacier in the Confucian Period (Pre-Cambrian), the Cacbonium - Permian and the Quatemari period.

The Ice Age of the dynasties appeared about 700-950 million years ago, now that the Earth has many places covered with thick ice, the thickest ice can reach several hundred meters, even thousands of meters. From Siberia to Northern China and downstream, middle In the history of the Earth that occurred three times in the past, it was the glacier in the Crumbles (Pre-Cambrian period), the Carboniferous period - Permian and Quatemari (Photo: potomacriver) Changjiang, from northwestern Europe to Africa, from North America to South Australia, almost everywhere is covered with snow and ice mountains.

The Ice Age of the Carbon - Permian appeared more than 200 million years ago. The effect of glaciers this time is mainly for Australia, South America and Africa in the Southern Hemisphere. Some places in South America and Africa still see traces of the glacier at the time.

Quatemari (Quaternary) was the last time, about 2 million years ago. The situation this time occurred relatively complicated, long time, sometimes intervening in a warm period, called ice cockroach period. According to geologists' research, this entire period has 4 ice ages and 3 ice-break periods. During the glacial period, in the high mountains of equatorial Africa, there were glaciers operating on a large scale. The Changjiang basin and the southwestern mountains of China also have active glaciers. After each glacial activity is an ice-break. At that time, the whole Earth was warming up, the ice was gradually falling, the glacial ice gradually retreated to the North. Trees in the middle latitude and lower area continue to grow, forest animals proliferate again.

Ice piercing is the product of the ice ages. There are two types of cross-bandages: One is transcontinental ice, the other is cross-mountain. Crossbows that see in Antarctica and in Greenland are across the continent, and those across the hills rarely meet. Currently in the high mountains on the high latitudes is still developing the cross-ice of the fourth ice age. The glacier with its tremendous power has created a unique landscape of cross-country geomorphology. Geomorphology across the hills and mountains has a sharp angle, with a kind of serrated, spherical type .