Table 7.22.

Study of exposed sections

Observation and investigation of exposed sectionsMethodApplicationsLimitations
Graphic
  • Observation of naturally exposed sections in gulley sides or coastal cliff sections;

  • Detailed logging and description of in situ sediments and structural assemblages;

  • Direct sampling from exposed sections

  • Direct correlation with landforms and development of sediment-landform associations;

  • Observation of structural relationships in detail not possible with drilling techniques;

  • Correlation of outcrops across a large study area;

  • Comparison of offshore borehole records with onshore geology.

  • Dangerous if attempted on unstable slopes. Anything other than remote viewing of structural detail likely to be precluded by H&S;

  • Relevant mainly to large-scale studies which require a more holistic approach to understanding the geology of a site.

Cost factor: very low
Relevance to glacial/periglacial depositsObservation of coastal cliffs or exposures in upland gulleys and river banks is the mainstay of academic investigation of Quaternary deposits. This approach is often overlooked by the private sector engineering geologist in favour of intrusive investigation techniques. H&S should be considered at all times and hazardous slopes should not be approached under any circumstances. While observing and sampling sediments in situ provides excellent detail on ground conditions, these are unlikely to relate specifically to the location of the development. The benefit of observing natural sections and outcrops should be considered where either a more holistic approach to site investigation is needed or when solving a more specific stratigraphical or process-form-related problem arises. Examples of such scenarios include the use of coastal cliff exposures to stratigraphically correlate or identify offshore glacial deposits. Figure 7.22 provides an example of the type of structural detail that can be identified and used to infer depositional processes across a large area. Inferring depositional processes and environments on this scale provides important information that can be used to predict other deposits across a site when expert knowledge is employed.
  • H&S are the requirements to satisfy national legislation for Health and Safety.