Contents

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Contents

• Introduction
• Unconsolidated clastic sediments
• Sedimentary rocks
• Diagenesis
• Sediment transport and deposition
• Sedimentary structures
• Facies and depositional environments
• Glacial/eolian/lacustrine environments
• Fluvial/deltaic/coastal environments
• Shallow/deep marine environments

• Stratigraphic principles
• Sequence stratigraphy
• Sedimentary basins
• Models in sedimentary geology
• Applied sedimentary geology
• Reflection

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Glacial/eolian/lacustrine environments

• Glacial environments
• Glaciers and ice sheets form where precipitation
  rates, in the form of snow (accumulation), exceed
  melting rates (ablation)
• Ice flows as a result of gravity and essentially
  acts like a high-viscosity fluid exhibiting
  laminar flow
• Temperate (warm-based) vs. polar (cold-based)
  glaciers reflect the temperature regime within
  the ice
• Ice shelves can form when a glacier or ice sheet
  reaches the coast and extends offshore, and
  ultimately breaks up into icebergs

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Glacial/eolian/lacustrine environments

• Glacial environments
• Abrasion leads to the formation of rock flour
  (mineralogically diverse silt- and clay-sized
  sediment grains) plucking results in coarser (up
  to boulder-sized) material
• Warm-based ice tends to be more erosive
  (abrasive) than cold-based ice
• Till/tillite (also known as diamict/diamictite)
  is poorly sorted, angular, and immature
• Lodgement till forms by active deposition under
  the ice (relatively compact and usually
  fractured)
• Meltout till forms passively during melting

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Glacial/eolian/lacustrine environments

• Glacial environments
• Abrasion leads to the formation of rock flour
  (mineralogically diverse silt- and clay-sized
  sediment grains) plucking results in coarser (up
  to boulder-sized) material
• Warm-based ice tends to be more erosive
  (abrasive) than cold-based ice
• Till/tillite (also known as diamict/diamictite)
  is poorly sorted, angular, and immature
• Lodgement till forms by active deposition under
  the ice (relatively compact and usually
  fractured)
• Meltout till forms passively during melting

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Glacial/eolian/lacustrine environments

• Glacial environments
• Glaciofluvial or fluvioglacial deposits are
  sediments formed in association with glacial
  meltwater (e.g., glacial outwash)
• More distal glaciolacustrine and glaciomarine
  deposits are typically dominated by fine-grained
  sediment (rock flour), along with ice-rafted
  debris and dropstones
• The preservation potential of glacial deposits is
  usually limited, with the exception of tills and
  glaciomarine deposits associated with big ice
  sheets

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Glacial/eolian/lacustrine environments

• Eolian environments
• Eolian deposits dominate deserts (mostly at low
  latitudes, but sometimes arctic), but are also
  important along shorelines (coastal dunes) and in
  association with ice sheets (loess)
• Air is a low-density and low-viscosity fluid
  therefore high flow velocities are required to
  enable sediment transport
• Eolian deposits are mostly texturally and
  mineralogically mature, due to the selective
  transport of specific grain sizes and the large
  impact of grain-to-grain collision

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Glacial/eolian/lacustrine environments

• Eolian environments
• Sand dunes are the most common eolian landforms
  their geometry and resulting sedimentary
  structures depend primarily on sediment supply
  and prevailing wind direction
• Large (gt5 m) sets of cross strata are very
  commonly eolian in origin
• Eolian sand sheets develop when sediment supply
  is limited and are characterized by planar
  stratification vegetation can contribute to dune
  formation under such circumstances
• Loess is a homogeneous, very well sorted,
  silt-dominated sediment that is deposited from
  suspension it is commonly associated with ice
  sheets that produce large quantities of source
  material (rock flour)

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Glacial/eolian/lacustrine environments

• Eolian environments
• Sand dunes are the most common eolian landforms
  their geometry and resulting sedimentary
  structures depend primarily on sediment supply
  and prevailing wind direction
• Large (gt5 m) sets of cross strata are very
  commonly eolian in origin
• Eolian sand sheets develop when sediment supply
  is limited and are characterized by planar
  stratification vegetation can contribute to dune
  formation under such circumstances
• Loess is a homogeneous, very well sorted,
  silt-dominated sediment that is deposited from
  suspension it is commonly associated with ice
  sheets that produce large quantities of source
  material (rock flour)

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Glacial/eolian/lacustrine environments

• Lacustrine environments
• Playa (saline) lakes are hydrologically closed,
  ephemeral water bodies that form in arid
  environments and are characterized by
  mud-evaporite couplets
• Freshwater lakes are permanent (commonly
  hydrologically open) water bodies
• Waves and relatively weak wind-driven currents
  constitute the main mechanisms of sediment
  transport
• Density stratification develops under seasonal
  climate conditions and when currents are limited

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Glacial/eolian/lacustrine environments

• Lacustrine environments
• Playa (saline) lakes are hydrologically closed,
  ephemeral water bodies that form in arid
  environments and are characterized by
  mud-evaporite couplets
• Freshwater lakes are permanent (commonly
  hydrologically open) water bodies
• Waves and relatively weak wind-driven currents
  constitute the main mechanisms of sediment
  transport
• Density stratification develops under seasonal
  climate conditions and when currents are limited

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Glacial/eolian/lacustrine environments

• Lacustrine environments
• Coarse sediments mainly occur on lake margins
  (lacustrine deltas, beaches)
• In the central parts of lakes, deposition occurs
  from suspension and by means of turbidity
  currents
• Stratified lakes promote the accumulation of
  organic matter and the formation of varves
  organics are especially important in small lakes
• Carbonates of both chemical and biogenic origin
  can contribute significantly to lake sediments

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Glacial/eolian/lacustrine environments

• Lacustrine environments
• The final stage of filling of lakes commonly
  involves an important organic component
• Hydrosere vertical succession of organic
  deposits associated with the transition from a
  limnic, through a telmatic, to a terrestrial
  environment
• Gyttja --gt fen peat --gt wood peat --gt moss peat

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