Geologically, a fjord (pronounced /fjɔrd/ ( listen) or pronounced /fiːɔrd/) is a long, narrow inlet with steep sides, created in a valley carved by glacial activity. Fjords are formed when a glacier cuts a U-shaped valley by abrasion of the surrounding bedrock. Many such valleys were formed during the recent ice age.

Glacial melting is accompanied by rebound of Earth's crust as the ice load and eroded sediment is removed (also called isostasy or glacial rebound). In some cases this rebound is faster than sea level rise. Most fjords are deeper than the adjacent sea; Sognefjord, Norway, reaches as much as 1,300 m (4,265 ft) below sea level.

Fjords generally have a sill or rise at their mouth caused by the previous glacier's terminal moraine, in many cases causing extreme currents and large saltwater rapids (see skookumchuck). Saltstraumen in Norway is often described as the worlds strongest tidal current. These characteristics distinguish fjords from rias (e.g. the Bay of Kotor), which are drowned valleys flooded by the rising sea.

As late as 2000, some of the world's largest coral reefs were discovered along the bottoms of the Norwegian fjords. These reefs were found in fjords from the north of Norway to the south. The marine life on the reefs is believed to be one of the most important reasons why the Norwegian coastline is such a generous fishing ground.

Since this discovery is fairly new, little research has been done. The reefs are host to thousands of lifeforms such as plankton, coral, anemones, fish, several species of sharks, and many more. Most are specially adapted to life under the greater pressure of the water column above it, and the total darkness of the deep sea.

Similar to 0 things you like: