Deep marine L7

• What are the sedimentary characteristics that need to be described in deep marine environments?

  Fall, slump, and slide deposits.
• What are the two principal flows that form submarine fans?

  Debris flows and turbidity flows.
• What processes are involved in mass gravity processes according to Stow (1994)?

  Bulk transport of material and sediment gravity flow processes.
• What triggers mass transport related to sediment delivery in marine basins?

  Seismic events, storms, and exceeding slope sediment bearing capacity.
• What is the movement characteristic of slides in deep marine environments?

  Movement of sediment downslope on a planar surface.
• What is the difference between slides and slumps in sediment movement?

  Slides are translational, while slumps show internal deformation.
• What is a significant cause of the Storegga Slide?

  Excess pore pressure due to sedimentation during peak glaciation.
• What is the typical slope angle associated with the Storegga Slide?

  10–20 degrees.
• What is the appearance of slumps on the sea floor?

  Hummocky appearance.
• What are the characteristics of debris flows in marine environments?

  Laminar flow that can incorporate water and fine upwards.
• How do turbidity flows differ from debris flows?

  Turbidity flows are less dense and sediment is suspended in water.
• What is the significance of the head, body, and tail in turbidity flows?

  They represent different flow characteristics: head is turbulent, body is uniform, and tail is diluted.
• What is the Bouma sequence?

  A sequence of sedimentary structures formed by turbidity currents.
• What are turbidite deposits characterized by?

  Grain size and density variations.
• What is the role of submarine fans in sediment deposition?

  They are bodies of sediment deposited from mass flows.
• What are canyons in the context of submarine fans?


  Large scale erosional features that deliver sediment into marine basins.
• What is the composition of hemipelagic sedimentation?

  Derived from nearby land masses and similar to continental composition.
• What are contourites and how are they formed?

  Deposits from semi-permanent ocean bottom currents influenced by geostrophic and thermohaline currents.
• Why are deep marine systems important?

  They can damage infrastructure and provide environmental records.
• What percentage of Earth's surface do deep marine systems cover?

  Approximately 70%.
• What are the different processes that result in sedimentation in deep marine systems?

  • Mass gravity processes
  • Bulk transport of material
  • Sediment gravity flow processes
  • Intra-basinal processes
  • Background sedimentation
• What are the characteristics of debris flows and turbidity flows?

  Debris flows:

  • Laminar flow
  • Can incorporate water
  • Poorly sorted deposits

  
  

  Turbidity flows:

  • Less dense than debris flows
  • Sediment suspended in water
  • Require a slope for movement
• What are the key features of submarine fans?

  • Bodies of sediment from mass flows
  • Formed by processes like slumps, slides, and turbidites
  • Composed of proximal, medial, and distal fan deposits
• What types of sedimentation occur in pelagic settings?

  • Biogenic sedimentation (e.g., foraminifera, coccoliths)
  • Non-biogenic sedimentation (e.g., terrigenous dust, volcanic ash)
  • Hemipelagic sedimentation from nearby land masses
• What are the implications of deep marine systems for environmental records?

  • They provide insights into sediment transport pathways
  • They are sources of hydrocarbons
  • They play a role in regulating Earth's temperature
• What are the challenges in recognizing contourite deposits?


  • Rarely recognized in the geologic record
  • Difficult to distinguish from turbidites
  • Seismic methods are improving recognition