Fjords (sometimes spelled fiords) are drowned glacier valleys. The depth of a fjord may exceed 1 mi (1.6 km) while the length sometimes exceeds 60 mi (97 km).
Geologic evidence indicates that some fjords form when a glacier cuts a deep, U-shaped valley through a river valley and advances into the sea. Given enough height and mass, the glacier may cut a valley into the sea floor as well. As it advances further into the sea, the glacier melts. The resulting reduction in size and mass causes the leading tongue of the glacier to float. A steep ridge is formed at the farthest reach of the glacier where the cutting stopped; this ridge is called a sill . In general, fjords can be identified by their steep sided, narrow channel, and sills.
Other evidence regarding the formation of fjords suggests that some of the deepest and most dramatic (such as those of Alaska, Norway, British Columbia, New Zealand, and other locations in the high latitudes) were formed during the most recent ice age. Evidence supports two scenarios to explain this process.
The first scenario suggests that some fjords resulted from landlocked glaciers . During the Ice Age, vast amounts of water were locked in enormous ice sheets. This reduced the availability of liquid water to Earth's oceans and exposed miles of coastline. In the coldest latitudes, glaciers excavated valleys as they moved onto the newly exposed coastline without ever reaching the sea. With the coming of warmer climatic conditions, ice sheets began to melt, causing the oceans to rise. At the same time, glaciers on the dry coastal shelves retreated. As they retreated, the rising seas filled the U-shaped valleys left behind.
The second scenario poses a combination of events that might account for the existence of some of the largest fjords. This explanation suggests that some glaciers did not remain land-locked on the coastal shelves during the ice age, but advanced for great distances and then continued their cutting on the sea floor. As the climate warmed, the rising seas occupied the deeply cut sea floor and advanced up the glacial valleys as the glaciers retreated.
It should be noted that fjords are classified as estuaries. However, due to their great depth and length, plus the height of their sills, they are semi-enclosed environments, similar to that of the open ocean. This characteristic sets fjords apart from all other estuarial environments.
See also Glacial landforms
"Fjords." World of Earth Science. . Encyclopedia.com. (June 23, 2018). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/fjords
"Fjords." World of Earth Science. . Retrieved June 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/fjords
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.