Formation of fjords

In the process of Quaternary glacier movement, a large number of U-shaped valleys can be formed by ground planing, and ice ridges are produced at the front edge of the U-shaped valleys. Later, as the glaciers melted and the sea level rose, the ice dike was submerged by seawater, and the seawater entered the U-shaped valley and became a fjord. At high latitudes, continental glaciers and island ice sheets can extend into the ocean, while glacial valley goes below the sea surface and continues to dig deep, expanding the ice bed. After the ice age, the sea level rose, and the lower end was submerged by seawater intrusion. Under the influence of seawater, a bay with flat and steep shore wall, wide valley bottom and deep water was formed, that is, a fjord.

The fjord is the result of the joint action of glaciers and oceans. Tens of thousands of years ago, huge glaciers cut the coastal land and formed a series of valleys. When glaciers melt, seawater flows back into the valley, forming a fjord.

process

During the fourth ice age, Scandinavia suffered from glacier erosion, forming various valleys. After a long historical period, the Atlantic Ocean returned to the Scandinavian valley, thus forming many fjords scenery headed by Songgen Fjord on the west coast of Norway today.

Cause of formation

First of all, glacier movement is the primary prerequisite for the formation of fjords, and only the erosion of glaciers can lay the foundation for the formation of fjords in the future. Throughout the world, almost all fjords were formed in the historical period after glacier erosion.

Secondly, the higher the latitude, the higher the relative frequency of fjord scenery distribution, because the temperature in high latitudes is low all the year round and it is more affected during the ice age. So the distribution of fjords is relatively more. Many fjords on the west coast of Norway, taking Songgen Fjord as an example, are located in the middle and high latitudes, which is a typical example. In addition, ocean currents also played a certain role in promoting the formation of fjords, especially coastal ocean currents. During the formation of Songgen Fjord on the west coast of Norway, the warm current of the North Atlantic brought the Atlantic ocean water into the valley on the west coast of Scandinavia. Therefore, the North Atlantic Warm Current played an indispensable role in the formation of the Norwegian West Coast Fjord.

Be distributed

The valley glaciers distributed in high latitude coastal areas and developed along the pre-glacial valley still have strong erosion ability after entering the sea, and continue to brush deep and widen the ice bed; After the ice age, influenced by seawater immersion, a bay with straight sides, steep cliffs, wide bottom and deep depth was formed, which was called a fjord. There is a 220km-long fjord off the coast of Norway, and the depth of the fjord off the coast of Patagonia in South America is1288m.