Turbidity current

Definition

A turbidity current is a fast-moving flow of sediment-laden water that occurs when sediment accumulates on the continental shelf and becomes unstable, triggering a rapid downslope movement. These currents can reshape the underwater landscape, transporting sediments from shallow to deep ocean areas and contributing to the formation of submarine canyons and other features. Understanding turbidity currents is crucial for studying submarine topography and bathymetry, as they play a significant role in sediment distribution and seafloor morphology.

5 Must Know Facts For Your Next Test

1. Turbidity currents can travel at speeds up to 60 miles per hour (97 kilometers per hour), making them one of the fastest sediment flows in the ocean.
2. These currents can carry a variety of sediments, including sand, silt, and clay, which can be deposited on the ocean floor and contribute to geological formations.
3. The occurrence of turbidity currents is often triggered by events such as earthquakes, storms, or river flooding that destabilize sediment on the continental shelf.
4. Turbidity currents play a vital role in shaping the ocean floor, contributing to the formation of features like submarine fans and deltas.
5. Monitoring turbidity currents is important for understanding sediment transport processes, which can impact marine ecosystems and underwater infrastructure.

Review Questions

• How do turbidity currents affect the morphology of submarine canyons?
  • Turbidity currents significantly influence the shape and structure of submarine canyons by eroding their sides and transporting sediments. As these fast-moving flows descend into deeper waters, they carve out narrow valleys and steep walls in the canyon, contributing to its development over time. The continuous movement of sediments by turbidity currents helps maintain the dynamic nature of these underwater features.
• Evaluate the environmental impacts of turbidity currents on marine ecosystems.
  • Turbidity currents can disrupt marine ecosystems by resuspending sediments and altering water clarity. When sediments are transported rapidly, they can bury benthic habitats, affecting organisms that rely on those environments for survival. Additionally, changes in water clarity can impact photosynthetic organisms like phytoplankton, disrupting food webs and overall ecosystem health.
• Analyze the role of turbidity currents in sediment transport and how this process influences underwater geological formations over time.
  • Turbidity currents are crucial for sediment transport in oceanic environments, as they move large volumes of sediment from continental shelves to deeper ocean basins. This process not only redistributes sediments but also leads to the creation of underwater geological formations such as submarine fans and deltas. Over time, the deposition of these sediments contributes to changes in seafloor topography and affects geological processes like plate tectonics and erosion.

Related terms

Submarine canyon: A deep, steep-sided valley cut into the seabed of the continental slope, often formed by the erosive action of turbidity currents.

Sediment plume: A mass of suspended particles in water, which can be caused by turbidity currents as they transport sediment through the ocean.

Continental shelf: The submerged border of a continent, extending from the coastline to the continental slope, where turbidity currents often originate.