Turbidity Currents

Definition

Turbidity currents are underwater flows of sediment-laden water that occur on the seafloor, driven by gravity. These currents can transport large volumes of sediments from continental shelves to deeper ocean basins, shaping marine sediment types and their distribution in the process. Their dynamic nature plays a crucial role in influencing sediment deposition, erosion, and overall seafloor morphology.

5 Must Know Facts For Your Next Test

1. Turbidity currents can travel at speeds of up to 100 km/h (62 mph) and can carry sediments over long distances across the ocean floor.
2. These currents are often triggered by disturbances such as underwater landslides, earthquakes, or storms that resuspend sediments and cause them to flow downhill.
3. As turbidity currents slow down, they deposit the sediments they carry, leading to the formation of graded beds that can be analyzed for geological studies.
4. The impact of turbidity currents can be seen in various marine sediment types, including turbidites, which are layered deposits formed from these flows.
5. Understanding turbidity currents is essential for marine geology and resource exploration because they influence sedimentary structures and can affect the habitats of benthic organisms.

Review Questions

• How do turbidity currents influence sediment distribution on the ocean floor?
  • Turbidity currents play a significant role in transporting sediment from shallower continental shelves to deeper ocean basins. As these sediment-laden flows move across the seafloor, they deposit materials when they lose energy, creating distinct sedimentary features such as turbidites. This process not only shapes the distribution of different sediment types but also impacts local ecosystems by altering habitats and influencing nutrient availability.
• Evaluate the factors that can trigger turbidity currents and discuss their implications for marine sediment transport.
  • Turbidity currents can be triggered by various factors such as underwater landslides, seismic activity, or heavy rainfall causing runoff. These disturbances resuspend sediments on the seabed and initiate gravity-driven flows. The implications of these events are profound: they can lead to significant reshaping of marine landscapes, affect sedimentation patterns, and disrupt local ecosystems. Understanding these triggers is crucial for predicting sediment transport dynamics in marine environments.
• Analyze how the study of turbidity currents contributes to our understanding of past oceanographic conditions and sedimentary processes.
  • Studying turbidity currents provides valuable insights into past oceanographic conditions through sedimentological records found in core samples. By examining features like graded bedding within turbidites, scientists can reconstruct historical events such as climatic changes or tectonic activities that influenced sediment transport processes. This analysis not only helps in understanding how sediments have been deposited over time but also offers context for contemporary marine geology and potential resource management strategies.

Related terms

Sediment Gravity Flows: Natural movements of sediment down slopes due to gravitational forces, which include turbidity currents as well as other forms like debris flows and slumps.

Submarine Canyon: Narrow, steep-sided valleys found on the seafloor that are often formed by the erosion caused by turbidity currents and can serve as pathways for these flows.

Marine Sediments: Particles that accumulate on the ocean floor, including mud, sand, and gravel, which can be transported by turbidity currents and affect their composition and distribution.