Mondo Knows Facts
Fjords are glacial valleys that the sea flooded
Ice cut the valleys below sea level, and when it melted the ocean moved in Glaciers grind a broad U-shaped trough with steep walls, unlike the V of a river valley. Fjords can be extraordinarily deep, with Sognefjord in Norway reaching about 1,300 metres. A shallow sill often lies across the mouth, which keeps the deep water still and poorly mixed. It sits in Mondo's world geography collection, one of 200 facts that each trace back to the reference below.
Where this comes from
Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.
Go further
More facts like this
Norway's coastline is longer than its land bordersMeasured around every fjord, Norway's mainland shore runs roughly 29,000 kilometresThe Svalbard Global Seed Vault protects crop diversity in permafrostBuilt deep inside a Norwegian Arctic mountain, the vault stores back-up seeds from around the globe.Perito Moreno is one of few stable glaciersWhile most glaciers shrink, this one advances and dams a lake until the ice gives wayIce cores trap ancient air for studyBubbles sealed in glacier ice preserve samples of the atmosphere from thousands of years agoThe Rwenzori has glaciers almost on the equatorThese peaks on the Uganda and Congo border carry ice despite sitting within a degree of the EquatorBlood Falls in Antarctica flows with crimson iron-rich waterEmerging from the Taylor Glacier, the waterfall gets its deep red colour from oxidised iron.
🗺️ World Geographyfact 129 of 200
← → to keep reading, or swipe
Tags: coastlines, glaciers, norway
Fjords are glacial valleys that the sea flooded: the short answers
- Where does this come from, and can I check it?
- Ice cut the valleys below sea level, and when it melted the ocean moved in. The figure is taken from National Geographic, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a world geography fact?
- Yes. It sits on the World Geography shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.