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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Unconsolidated clastic sediments

• Particles (or clasts) are the basic elements of
  any sediment
• Clastic (terrigenous clastic or siliciclastic)
  sediments (80-85 of the stratigraphic record)
  consist of particles derived from pre-existing
  rocks, as opposed to non-clastic sediments
• Texture
• Grain (particle) size
• Grain shape
• Clast/matrix relationships
• Fabric
• Lithology is the general characterization of a
  sediment or a sedimentary rock (e.g., coarse
  sand, mudstone)

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Unconsolidated clastic sediments

• The Udden-Wentworth grain-size scale is based on
  factors of two ? -log2 (mm)
• Mud (lt63 ?m gt4 ?)
• Clay (lt4 ?m gt8 ?)
• Silt (463 ?m 48 ?)
• Sand (632000 ?m -14 ?)
• Gravel (gt2000 ?m lt-1 ?)
• Grain-size (particle-size, granulometric)
  analysis
• The old-fashioned way direct measurement
  (gravel) and sieve/pipette analysis (sand and
  mud)
• The modern technology laser particle sizing
  (sand and mud)

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Unconsolidated clastic sediments

• The Udden-Wentworth grain-size scale is based on
  factors of two ? -log2 (mm)
• Mud (lt63 ?m gt4 ?)
• Clay (lt4 ?m gt8 ?)
• Silt (463 ?m 48 ?)
• Sand (632000 ?m -14 ?)
• Gravel (gt2000 ?m lt-1 ?)
• Grain-size (particle-size, granulometric)
  analysis
• The old-fashioned way direct measurement
  (gravel) and sieve/pipette analysis (sand and
  mud)
• The modern technology laser particle sizing
  (sand and mud)

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Unconsolidated clastic sediments

• Moment measures
• First moment mean (cf. median, mode)
• Premier measure of the grain size
• Second moment variance (cf. standard deviation)
• Measure of the degree of sorting
• (? standard deviation)
• Third moment skewness
• Measure of the symmetry of the grain-size
  distribution

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Unconsolidated clastic sediments

• Grain shape
• Roundness (well rounded to very angular)
• Sphericity (high or low)
• Clast/matrix proportion
• The matrix is the relatively fine-grained
  material that lies between the relatively
  coarse-grained clasts
• Clast-supported sediments (clasts are in direct
  contact)
• Matrix-supported sediments (clasts are entirely
  surrounded by matrix)
• Fabric
• Preferential orientation of particles in a
  sediment or tendency of a rock to break in
  specific directions

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Unconsolidated clastic sediments

• Sediment composition
• Detrital mineral grains (quartz, feldspar, mica,
  heavy minerals)
• Lithic fragments (polymineral grains or rock
  fragments)
• Detrital mineral grains dominate in silts, lithic
  fragments dominate in gravels
• Sediment maturity (degree of change compared to
  original bedrock provides evidence on the
  history of a sediment)
• Textural (mud content, sorting, grain shape)
• Mineralogical (proportion of stable or resistant
  minerals)
• Pitfalls! (depends strongly on the nature of the
  original bedrock)

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Unconsolidated clastic sediments

• Sediment composition
• Detrital mineral grains (quartz, feldspar, mica,
  heavy minerals)
• Lithic fragments (polymineral grains or rock
  fragments)
• Detrital mineral grains dominate in silts, lithic
  fragments dominate in gravels
• Sediment maturity (degree of change compared to
  original bedrock provides evidence on the
  history of a sediment)
• Textural (mud content, sorting, grain shape)
• Mineralogical (proportion of stable or resistant
  minerals)
• Pitfalls! (depends strongly on the nature of the
  original bedrock)

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Unconsolidated clastic sediments

• Clay minerals
• Clay minerals are phyllosilicates with layered
  crystal structures
• Kandite group (two layers) kaolinite
• Smectite group (three layers) montmorillonite,
  illite, chlorite
• Key physical and chemical characteristics of clay
  minerals
• Platy shape (easy to keep in suspension, very
  slow settling rates)
• Strong cohesion due to electrostatic charge
  (relatively difficult to erode, tendency to
  flocculate)

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Unconsolidated clastic sediments

• Clay minerals
• Clay minerals are phyllosilicates with layered
  crystal structures
• Kandite group (two layers) kaolinite
• Smectite group (three layers) montmorillonite,
  illite, chlorite
• Key physical and chemical characteristics of clay
  minerals
• Platy shape (easy to keep in suspension, very
  slow settling rates)
• Strong cohesion due to electrostatic charge
  (relatively difficult to erode, tendency to
  flocculate)