Sediment dispersal

  • Understand general nature of depositional environment prior to dip picking during reconnaissance pass of image analysis. Establish appropriate dip picking scheme. Use hierarchy approach if data and succession suitable.
  • Use dip-picking scheme to allow classification of cross-beds and a hierarchy of associated bounding surfaces and macroforms.
  • Subtract structural tilt and re-classify dip types based on palaeohorizontal inclination.
  • Zone the section into distinct sedimentary packets (e.g. parasequences, bed sets, individual channels or sand packets), tied-in with well stratigraphy and structural zonation.
  • Examine bedding surfaces on interactive stereonets with azimuth and strike histogram overlays. In horizontal wells it may be possible to establish dune migration direction where whole trough sets are sampled, using advanced stereographic analysis.
  • In fluvial sections an estimation of mean palaeo-river depth can be made using mean macroform thickness.
  • Determine relationship of bounding surfaces to each other and cross-bedding.
  • Use peak counts from contours, vector means and eigenvector methods to establish measures of central tendency.
  • Interpret orientation fabrics for cross-bedding to assess palaeotransport trends within sedimentary packets.
  • Assess orientation of macroforms in order to interpret large-scale sedimentary attitudes, where present (e.g. axial bar forms, point bars or elongate sand bars).
  • For deep marine sections use deformed bedding & slumps/slides to estimate palaeoslope strike and up-slope direction where block rotation is recognised.