silt
/sɪlt
/noun [mass noun]
1Fine sand, clay, or other material carried by running water and deposited as a sediment, especially in a channel or harbour.Water continuing out over the playa surface carries with it a quantity of fine sand, silt, and clay in suspension....
- However, in addition to that alluvium much of central Belfast is underlain instead by a deposit of soft grey mud, silt and fine sand with numerous sea shells, in particular oysters.
- Excavations in 1990 added weight to the idea that the horse dates from later prehistory as deposits of fine silt in the beak were scientifically dated to the early first millennium BC.
Synonyms
sediment, deposit, alluvium, mud, slime, ooze, sludge;
sand, clay
1.1 [count noun] A bed or layer of silt.In fact, badlands occur in a wide range of environments, and on various materials, from marine silts in valleys of the Canadian Arctic to mine-spoil heaps in New Guinea....
- Carbonaceous plant debris is concentrated in finely laminated silts and mudstones at the tops of some beds.
- The sediments include lacustrine freshwater limestones, silts, marls, occasional sands and local lignite.
1.2 technical Sediment whose particles are between clay and sand in size (typically 0.002-0.06 mm).The textures of soils reflect the proportion of sand, silt, and clay sizes within that portion of an inorganic soil fraction that is less than 2 mm....
- This is soil whose properties are controlled equally by the percentages of clay, silt and sand particles.
- The way sand, silt and clay particles are grouped together in aggregates is called the soil structure.
verb [no object]
1Become filled or blocked with silt: the river’s mouth had silted up (as noun silting) the silting of the river estuary...
- The defendants erected ferry terminals in the Thames, and, as a result, parts of the river bed silted up.
- Of course, we would be told that the river has now silted up and that at low tide it would be impossible.
- Old Goa remained the colony's capital until I759, when the Mandovi River silted up.
Synonyms
become blocked, become choked, become clogged, fill up (with silt), become filled, become dammed
1.1 [with object] Fill or block with silt: the soil ends up silting up the stream (as adjective silted) the silted mouth of the river...
- There are no open drains, fortunately, or they'd be silted by now.
- Local people cultivate tapioca, rice and vegetables on the heavily silted riverbed.
- The lagoon will also have to be dredged as it is heavily silted and the fish are dying because the water is too shallow and the lagoon is not being adequately flushed.
Derivatives
siltation
- In addition to predation and competition by exotic species, these fish were also negatively impacted by overfishing, pollution, siltation and other forms of habitat degradation.
- It says the crop has triggered soil erosion, siltation of waterways, widespread use of toxic chemicals and pesticides and road building through some of the world's most delicate habitats.
- Additionally, once logged, many national forests are prone to flooding, mudslides and stream destruction due to runoff and siltation.
silty
/ adjective (siltier, siltiest) ...- Near the top of the succession blue-grey silty calcareous mudstones are interbedded with subordinate graded sandstones.
- These soils consist of moderately deep to deep, moderately well - to well-drained silt loam surface soils and loam, silty clay loam, or silty clay subsoils.
- The Eocene London Clay is a succession of marine silty clays, clayey and sandy silts, and subordinate sands reaching a thickness of over 165 m on the Isle of Sheppey, Kent, UK.
Origin
Late Middle English: probably originally denoting a salty deposit and of Scandinavian origin, related to Danish and Norwegian sylt 'salt marsh', also to salt.