Contents

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Contents

• Introduction
• Sedimentology concepts
• Fluvial environments
• Deltaic environments
• Coastal environments
• Offshore marine environments

• Sea-level change
• Sequence stratigraphy concepts
• Marine sequence stratigraphy
• Nonmarine sequence stratigraphy
• Basin and reservoir modeling
• Reflection

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Offshore marine environments

• Shallow marine environments include
  pericontinental seas that occur along continental
  margins and have a shoreline-shelf-slope profile
  and epicontinental seas that cover continental
  interiors and exhibit a ramp morphology
• Under idealized conditions the offshore-transition
  and offshore exhibit a systematic decrease in
  (wave) energy and grain size however, such an
  equilibrium shelf is commonly not encountered
• Tides and ocean currents can strongly complicate
  shelf hydrodynamics
• Rapid sea-level changes (e.g., during the
  Quaternary) result in relict shelf sediments that
  are genetically unrelated to the present
  conditions

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Offshore marine environments

• Shallow marine environments include
  pericontinental seas that occur along continental
  margins and have a shoreline-shelf-slope profile
  and epicontinental seas that cover continental
  interiors and exhibit a ramp morphology
• Under idealized conditions the offshore-transition
  and offshore exhibit a systematic decrease in
  (wave) energy and grain size however, such an
  equilibrium shelf is commonly not encountered
• Tides and ocean currents can strongly complicate
  shelf hydrodynamics
• Rapid sea-level changes (e.g., during the
  Quaternary) result in relict shelf sediments that
  are genetically unrelated to the present
  conditions

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Offshore marine environments

• Wave/storm-dominated shelves ideally exhibit a
  transition from sands in the lower shoreface, to
  alternating sands and muds below fairweather wave
  base, to muddy facies below storm wave base
• Storms have a strong imprint (i.e., storm
  deposits have a high preservation potential),
  since they wipe out fairweather deposits
• Tempestites form during storm events and exhibit
  a characteristic facies succession from an
  erosional basal surface with sole marks, to a
  sandy unit with hummocky cross stratification
  overlain by wave-rippled sand, finally giving way
  to muds

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Offshore marine environments

• Wave/storm-dominated shelves ideally exhibit a
  transition from sands in the lower shoreface, to
  alternating sands and muds below fairweather wave
  base, to muddy facies below storm wave base
• Storms have a strong imprint (i.e., storm
  deposits have a high preservation potential),
  since they wipe out fairweather deposits
• Tempestites form during storm events and exhibit
  a characteristic facies succession from an
  erosional basal surface with sole marks, to a
  sandy unit with hummocky cross stratification
  overlain by wave-rippled sand, finally giving way
  to muds

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Offshore marine environments

• Tides lead to circulation around amphidromic
  points, ranging from circular to almost
  rectilinear depending on the shape of the water
  body
• Tide-dominated shelves exhibit a distinct suite
  of bedforms in relation to current velocity and
  sediment (sand) supply
• Erosional features, sand ribbons, and sand waves
  go along with decreasing flow velocities,
  commonly associated with mud-draped subaqueous
  dunes tidal sand ridges (tens of m high, many km
  across) are characteristic of shelves with a high
  supply of sand

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Offshore marine environments

• Tides lead to circulation around amphidromic
  points, ranging from circular to almost
  rectilinear depending on the shape of the water
  body
• Tide-dominated shelves exhibit a distinct suite
  of bedforms in relation to current velocity and
  sediment (sand) supply
• Erosional features, sand ribbons, and sand waves
  go along with decreasing flow velocities,
  commonly associated with mud-draped subaqueous
  dunes tidal sand ridges (tens of m high, many km
  across) are characteristic of shelves with a high
  supply of sand

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Offshore marine environments

• Ocean current-dominated shelves are relatively
  rare geostrophic ocean currents can lead to the
  formation of bedforms that are somewhat
  comparable to those of tide-dominated shelves
• Mud-dominated shelves are usually associated with
  large, tropical rivers with a high suspended load
  (e.g., Amazon and Yellow Rivers) that can be
  transported along the shelf if currents are
  favorable

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Offshore marine environments

• Deep marine environments include the continental
  slope and the deep sea
• Subaqueous mass movements (mostly sediment
  gravity flows) involve a range of transport
  mechanisms, including plastic flows and fluidal
  flows
• Debris flows are commonly laminar and typically
  do not produce sedimentary structures
• Turbidity currents are primarily turbulent and
  more diluted they commonly evolve from debris
  flows
• Debris-flow deposits are poorly sorted, related
  to the freezing that occurs once shear stresses
  can not overcome the internal shear strength
• A key mechanism in turbidity currents is
  autosuspension (turbulence --gt suspended load
  --gt excess density --gt flow --gt turbulence)

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Animation
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Offshore marine environments

• Deep marine environments include the continental
  slope and the deep sea
• Subaqueous mass movements (mostly sediment
  gravity flows) involve a range of transport
  mechanisms, including plastic flows and fluidal
  flows
• Debris flows are commonly laminar and typically
  do not produce sedimentary structures
• Turbidity currents are primarily turbulent and
  more diluted they commonly evolve from debris
  flows
• Debris-flow deposits are poorly sorted, related
  to the freezing that occurs once shear stresses
  can not overcome the internal shear strength
• A key mechanism in turbidity currents is
  autosuspension (turbulence --gt suspended load
  --gt excess density --gt flow --gt turbulence)

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Offshore marine environments

• Deep marine environments include the continental
  slope and the deep sea
• Subaqueous mass movements (mostly sediment
  gravity flows) involve a range of transport
  mechanisms, including plastic flows and fluidal
  flows
• Debris flows are commonly laminar and typically
  do not produce sedimentary structures
• Turbidity currents are primarily turbulent and
  more diluted they commonly evolve from debris
  flows
• Debris-flow deposits are poorly sorted, related
  to the freezing that occurs once shear stresses
  can not overcome the internal shear strength
• A key mechanism in turbidity currents is
  autosuspension (turbulence --gt suspended load
  --gt excess density --gt flow --gt turbulence)

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Animation 1
Animation 2
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Offshore marine environments

• Contrary to debris flows, turbidites exhibit a
  distinct proximal to distal fining
• The idealized Bouma sequence, consisting of
  divisions A-E, is most useful for medium-grained,
  sand-mud turbidites, but it must be applied with
  care
• A Rapidly deposited, massive sand
• B Planar stratified (upper-stage plane bed) sand
• C Small-scale (climbing ripple) cross-stratified
  fine sand
• D Laminated silt
• E Homogeneous mud
• High-density and low-density turbidity currents
  give rise to incomplete, coarse-grained (A) and
  fine-grained (D-E) turbidites respectively
• Contourites are formed by ocean currents and
  commonly represent reworked turbidites

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Offshore marine environments

• Contrary to debris flows, turbidites exhibit a
  distinct proximal to distal fining
• The idealized Bouma sequence, consisting of
  divisions A-E, is most useful for medium-grained,
  sand-mud turbidites, but it must be applied with
  care
• A Rapidly deposited, massive sand
• B Planar stratified (upper-stage plane bed) sand
• C Small-scale (climbing ripple) cross-stratified
  fine sand
• D Laminated silt
• E Homogeneous mud
• High-density and low-density turbidity currents
  give rise to incomplete, coarse-grained (A) and
  fine-grained (D-E) turbidites respectively
• Contourites are formed by ocean currents and
  commonly represent reworked turbidites

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Offshore marine environments

• Submarine canyons at the shelf edge (commonly
  related to deltas) are connected to submarine
  fans on the ocean floor
• The size of submarine fans is inversely related
  to dominant grain size (i.e., mud-dominated
  submarine fans are 104106 km2, sand or
  gravel-dominated submarine fans are 101102 km2)
• Submarine fans share several characteristics with
  deltas they consist of a feeder channel that
  divides into numerous distributary channels
  bordered by natural levees (channel-levee
  systems) and are subject to avulsions
• Proximal fan (trunk channel)
• Medial fan (lobes)
• Distal fan

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Animation
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Offshore marine environments

• Submarine canyons at the shelf edge (commonly
  related to deltas) are connected to submarine
  fans on the ocean floor
• The size of submarine fans is inversely related
  to dominant grain size (i.e., mud-dominated
  submarine fans are 104106 km2, sand or
  gravel-dominated submarine fans are 101102 km2)
• Submarine fans share several characteristics with
  deltas they consist of a feeder channel that
  divides into numerous distributary channels
  bordered by natural levees (channel-levee
  systems) and are subject to avulsions
• Proximal fan (trunk channel)
• Medial fan (lobes)
• Distal fan

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Offshore marine environments

• Hemipelagic sediments consist for at least 25 of
  fine-grained (muddy) terrigenous material that is
  deposited from suspension, commmonly after
  transport by hemipelagic advection
• Distal, muddy turbidites merge gradationally into
  hemipelagic deposits
• Eolian dust is an important component (50) of
  hemipelagic (and pelagic) facies
• Black shales have a 115 organic-matter content
  and form in anoxic bottom waters, sometimes in
  shallow seas (e.g., Western Interior Seaway)
• Pelagic sediments are widespread in the open
  ocean and primarily have a biogenic origin