An underwater current of usually rapidly moving, sediment-laden water moving down a slope
Turbidites are deposited in the deep ocean troughs below the continental shelf, or similar structures in deep lakes, by turbidity currents which slide down the slopes.Longitudinal section through an underwater turbidity current
A turbidity current is most typically an underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in the process.[1] Turbidity currents can also occur in other fluids besides water.
Researchers from the Monterey Bay Aquarium Research Institute found that a layer of water-saturated sediment moved rapidly over the seafloor and mobilized the upper few meters of the preexisting seafloor. Plumes of sediment-laden water were observed during turbidity current events but they believe that these were secondary to the pulse of the seafloor sediment moving during the events. The belief of the researchers is that the water flow is the tail-end of the process that starts at the seafloor.[1]
In the most typical case of oceanic turbidity currents, sediment laden waters situated over sloping ground will flow down-hill because they have a higher density than the adjacent waters. The driving force behind a turbidity current is gravity acting on the high density of the sediments temporarily suspended within a fluid. These semi-suspended solids make the average density of the sediment bearing water greater than that of the surrounding, undisturbed water.
As such currents flow, they often have a "snow-balling-effect", as they stir up the ground over which they flow, and gather even more sedimentary particles in their current. Their passage leaves the ground over which they flow scoured and eroded. Once an oceanic turbidity current reaches the calmer waters of the flatter area of the abyssal plain (main oceanic floor), the particles borne by the current settle out of the water column. The sedimentary deposit of a turbidity current is called a turbidite.
Seafloor turbidity currents are often the result of sediment-laden river outflows, and can sometimes be initiated by earthquakes, slumping and other soil disturbances. They are characterized by a well-defined advance-front, also known as the current's head, and are followed by the current's main body. In terms of the more often observed and more familiar above sea-level phenomenon, they somewhat resemble flash floods.
Turbidity currents can sometimes result from submarine seismic instability, which is common with steep underwater slopes, and especially with submarine trench slopes of convergent plate margins, continental slopes and submarine canyons of passive margins. With an increasing continental shelf slope, current velocity increases, as the velocity of the flow increases, turbulence increases, and the current draws up more sediment. The increase in sediment also adds to the density of the current, and thus increases its velocity even further.
^ ab"'Turbidity currents' are not just currents, but involve movement of the seafloor itself". EurekAlert!. Monterey Bay Aquarium Research Institute. 5 October 2018. Retrieved 8 October 2018.
A turbiditycurrent is most typically an underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research...
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its own current type. This is the turbiditycurrent. Turbiditycurrent is caused when the density of water is increased by sediment. This current is the...
a turbidity reading), a correlation between turbidity and total suspended solids (TSS) is somewhat unusual for each location or situation. Turbidity in...
suggested that a 60-mile-per-hour (100 km/h) submarine landslide or turbiditycurrent of water-saturated sediments swept 400 miles (600 km) down the continental...
structures in turbidite sandstone beds that are deposited by high-density turbiditycurrents. It is intended to complement, not replace, the better known Bouma...
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are hypothesized to have been deposited by turbiditycurrents. A turbiditycurrent is an underwater current that moves rapidly and carries sediment. This...
submarine canyons serve as channels for the flow of turbiditycurrents across the seafloor. Turbiditycurrents are flows of dense, sediment laden waters that...
slopes, the sedimentary cover can become unstable, causing turbiditycurrents. Turbiditycurrents are sudden disturbances of the normally quiet deep marine...
turbiditycurrents, avalanches, discharge from wastewater or industrial processes into rivers, or river discharge into the ocean. Gravity currents are...
subaqueous settings. However, grain-to-grain interactions in high-density turbiditycurrents are very important as a contributing mechanism of sediment support...
fluid turbulence. They are particle-laden gravity currents and closely related to turbiditycurrents, pyroclastic flows from volcanoes and dust storms...
about 40 million years ago. It contains one of the world's largest turbiditycurrent channel systems, the Northwest Atlantic Mid-Ocean Channel (NAMOC)...
sediments, mainly clay and silt. Much of this sediment is deposited by turbiditycurrents that have been channelled from the continental margins along submarine...
of downcutting. At this time, apparently the channel built up by turbiditycurrent that proceeded south, along the western part of the Cascadia abyssal...
earthquakes or other geological disturbances. These can result in turbiditycurrents as turbid water dense with suspended sediment rushes down the slope. Chaotic...
to suspended materials. When the slope of the bed (over which the turbiditycurrent flows) flattens, the slower rate of flow is mirrored by increased...
classic set of sedimentary structures in turbidite beds deposited by turbiditycurrents at the bottoms of lakes, oceans and rivers. The Bouma sequence specifically...
continent, and was formed by the underwater erosion process known as turbiditycurrent erosion. Many questions remain unresolved regarding the exact nature...
any noticeable change into turbiditycurrents, as shown in figure 3 while others completely change into turbiditycurrents near to the source. This variation...
out of ambient temperature water Turbidite – Geologic deposit of a turbiditycurrent Wackestone – Mud-supported carbonate rock that contains greater than...
sediment-laden water that move rapidly downslope as turbiditycurrents. Where erosion by turbiditycurrents creates oversteepened slopes it can also trigger...
Unlike canyons on land, submarine canyons are thought to be formed by turbiditycurrents and landslides. The word canyon is Spanish in origin (cañón, pronounced...
(310 mi) from the slope, it consists of thick sediments deposited by turbiditycurrents from the shelf and slope. The continental rise's gradient is intermediate...
to the discovery of the landslide and the first documentation of a turbiditycurrent. Scientists have examined layers of sand, believed to be deposited...
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