Learning Outcomes:
On completion of this module, you should be able to:
- Work from a 1D stratigraphic section to make predictions in3D and time.
- Apply understanding from Holocene systems and outcrop analogues.
- Use biostratigraphy to erect a stratigraphical framework and constrain palaeoenvironments.
- Construct correlation panels using sequence stratigraphic principles
- Build serial gross depositional environment (GDE) maps to predict spatial variations in lithology.
Indicative Module Content:
Lectures (50 minutes)
Lecture 1: Introduction to stratigraphic principles
The stratigraphic record – rates, scales and gaps. Steno’s laws in the subsurface. Clinoforms and clinothems. Way-up. Bed geometry. Relationship between litho-, bio- and chronostratigraphy. Unconformities and surface-based correlation. Event stratigraphy.
Lecture 2: Facies concept – 1D to 4D
Facies, facies associations and facies successions. Architectural elements. Systems tracts. Relationship between depositional environments and depositional systems. Walther’s Law. Shoreline processes. Stratigraphy generated by regressive and transgressive shorelines. Accommodation and the A:S ratio. Auto vs. allogenic controls on deposition.
Lecture 3: Generating stratigraphy
Concept of stratigraphic base-level on different sectors of the depositional profile. Compensational stacking. River channels and floodplain deposits. Reconstructing alluvial stratigraphy in the subsurface. Multilateral and multistorey sandbodies. Compensation, anti-compensation and channel stacking patterns. Climate and tectonic controls on channel connectivity. Implications for groundwater aquifers (NW India and US High Plains).
Lecture 4: Modern coastal settings – what lies beneath?
Main paralic settings and relationship to A:S. Importance of process mix (river discharge, tides, waves). Stratigraphic lessons from high-resolution characterisation of the Holocene Mississippi and Po delta systems, the Sendai plain and the Gironde estuary. Distinguishing delta from estuarine systems.
Lecture 5: Biostratigraphy 1
Basic principles of biostratigraphy (P1). Key concepts: homotaxy; diachrony; biozones; biochronozones. Key attributes of a zone fossil. Criteria for definition of biozones. Challenge of reworked fossils.
Lecture 6: Biostratigraphy 2
Important microfossil groups: their environmental and temporal distribution. Coupling biostratigraphy to a geochronological framework (P2). Applications in paleoenvironmental analysis and definition of GDEs. Incorporation of biostratigraphy into sequence stratigraphy.
Lecture 7: Introduction to sequence stratigraphy
Origin of surface based stratigraphic subdivision. The slug diagram – what it does and does not represent. Eustatic and relative sea level change. Concept of sediment volume partitioning. Margin response to a fall and then rise of sea level. Origin of key stratigraphic surfaces: subaerial unconformity, correlative conformity, maximum regressive surface, transgressive surface and maximum flooding surface. Surfaces and time.
Lecture 8: Parasequences and sequence sub-division
Shallow-water parasequences and flooding surfaces. Expression of parasequences in different settings. Parasequence stacking patterns - progradational, aggradational and retrogradational. Relationship to shoreline trajectories and position in sequence. Products of normal vs forced regression. Surface expression. Contrasting approaches to sequence subdivision.
Lecture 9: Surface-based correlation in practice
Outline of typical workflow. Gross depositional environment maps (the predictive element). Importance of the choice of datum. Honouring rational depositional trends (pitfall of like-to-like correlation). Moving away from the shoreline – approaches to non-marine and deep-water stratigraphy.
Lecture 10: Additional stratigraphic tools
Source to sink (S2S) analysis – basin scale prediction. Compositional and heavy mineral stratigraphy in barren strata. Chemostratigraphy. Clay mineralogy. Magnetostratigraphy. Cyclostratigraphy and cyclothems. Event stratigraphy.
Practicals (3 hour sessions)
Practical 1:
Predicting stratigraphic relationships away from a vertical section. (A) Sorbas Member, SE Spain and (B) Aren Sandstone, south-central Pyrenees.
Practical 2:
Cocco delta exercise. Reconstructing Holocene history and shallow subsurface stratigraphy from Google Earth imagery.
Practical 3:
Biostratigraphic exercises. (1) Alternative correlations via lithostratigraphy, event stratigraphy, biostratigraphy. (2) Microfossils and biostratigraphy: establishing the geochronology of ODP Leg 198 Site 1208A, Shatsky Rise, NW Pacific. (3) Using microfossil datum levels to calculate sedimentation rates.
Practical 4:
Surface based correlation exercises.
Practical 5:
Ferron Sandstone correlation using behind-outcrop boreholes and generation of GDE maps.