Geological fieldwork techniques (mapping and logging)

Geological Fieldwork Techniques

Geological mapping involves observing and recording the spatial distribution and orientation of rock units and structures on the Earth’s surface.
Learn to identify different rocks and minerals in the field based on visual and tactile characteristics.
Develop proficiency with a geological compass-clinometer - an instrument used to measure the direction and angle of planes (like bedding planes) and linear features (like fold axes).
Make sure to orientate the geological map in the field to the compass directions - this will enable accurate location of your position and identified features.
Marked geological boundaries should be positioned at the point where one rock type changes to another, indicating a change in history or conditions of deposition, renovation, or intrusion.
The scale of your map should be noted and kept consistent.
Any structural symbols used in your map must conform to the convention specified by the British Geological Survey.

The formation log, or stratigraphic log, is a graphical representation showing the vertical distribution of different rock units in a particular location.
The log should include thickness measurements of beds/layers and their lithology, including grain size, sedimentary structures, mineral content, colour and fossils, if present.
Note the contacts between different beds, whether they’re gradational, erosional, or sharp.
Field sketches can be used alongside the log to illustrate unusual or important features seen.
Keep the scale of thickness consistent in your log and remember to show any gaps in succession - they correspond to periods of non-deposition or erosion, known as unconformities.
Note down the presence of any deformation structures such as folds or faults, as these provide important insights into past tectonic events.

Always carry appropriate field equipment, including a first aid kit, a map of the area, a whistle for attracting attention, and sufficient food and water.
Dress appropriately for the weather and terrain.
Inform others of your fieldwork plans and expected return time, and never undertake fieldwork alone in remote areas.
Stay alert when near cliff edges and never dislodge rocks on cliff faces, as it can be hazardous to you and others.