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DUNE
| Pronunciation (US): |  | (GB): | |
I. (noun)
Sense 1
Meaning:
A ridge of sand created by the wind; found in deserts or near lakes and oceans
Synonyms:
dune; sand dune
Classified under:
Nouns denoting natural objects (not man-made)
Hypernyms ("dune" is a kind of...):
ridge (a long narrow natural elevation or striation)
Hyponyms (each of the following is a kind of "dune"):
seif dune (a long and tall sand dune with a sharp crest; common in the Sahara)
Context examples:
This interaction is controlled by turbulent swirls from the upstream dune, which push the downstream dune away.
(Sand dunes can ‘communicate’ with each other, University of Cambridge)
Now we can add another analogy with Earth and Mars: the active dust cycle, in which organic dust can be raised from large dune fields around Titan's equator.
(Dust Storms on Titan Spotted for the First Time, NASA)
“This makes the grains so sticky and cohesive that only heavy winds can move them. The prevailing winds aren’t strong enough to shape the dunes.”
('Electric Sands' Cover Titan, VOA News)
Continuing examination of these still-perplexing seasonal dark streaks with a powerful camera on NASA's Mars Reconnaissance Orbiter (MRO) shows they exist only on slopes steep enough for dry grains to descend the way they do on faces of active dunes.
(Recurring Martian Streaks: Flowing Sand, Not Water?, NASA)
Some of the dark sandstone in an area being explored by NASA's Curiosity Mars rover shows texture and inclined bedding structures characteristic of deposits that formed as sand dunes, then were cemented into rock.
(Mars Panorama from Curiosity Shows Petrified Sand Dunes, NASA)
Dunes transform from stable to active after plant cover is reduced beyond a critical level.
(Sleeping sands of the Kalahari awaken after more than 10,000 years, NSF)
A team from the University of Cambridge has found that as they move, sand dunes interact with and repel their downstream neighbours.
(Sand dunes can ‘communicate’ with each other, University of Cambridge)
The winds could be transporting the dust raised from the dunes across large distances, contributing to the global cycle of organic dust on Titan and causing similar effects to those that can be observed on Earth and Mars.
(Dust Storms on Titan Spotted for the First Time, NASA)
In the Kalahari, dune mobilization is ongoing, especially in overgrazed areas close to boreholes and villages, D'Odorico and Okin have found.
(Sleeping sands of the Kalahari awaken after more than 10,000 years, NSF)
The results, are key for the study of long-term dune migration, which threatens shipping channels, increases desertification, and can bury infrastructure such as highways.
(Sand dunes can ‘communicate’ with each other, University of Cambridge)
