Geoscience Reference
In-Depth Information
If the area is unknown it might be useful to run a pilot study
with a low-resolution grid fi rst, followed by a higher resolution
study over the area of interest. Care also needs to be taken to
ensure that suffi cient data are collected to delineate the edge of
the geological feature under investigation.
In all but exceptional circumstances the data should be
collected at regularly spaced intervals so the mathematical
processing that will need to be done later is easier. Maps,
satellite images, GPS and/or surveying equipment should be
used to set up large-scale grids. Small-scale grids and
stratigraphic transects can be established using tapes, rules, a
Jacob staff and compass (Section 2.5). Care should be taken to
measure not only the distance between measurement stations
but also the total distance between a number of measurement
stations to check for cumulative error. For instance, if the
measurements are taken every 10 cm check that the 1 m stations
are correctly positioned relative to each other.
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11.2 Transport and protection of
the instruments
Some forethought needs to be applied to transporting
electronic equipment in the fi eld. Larger backpacks/rucksacks
and/or one of the specially designed carrying cases may be
necessary. However, some compromise between bulk and
padding will need to be struck. All electronic equipment
needs to be protected against rain and particularly saltwater.
A large umbrella or mountain shelter tent can be useful under
wet conditions. Carry spares of smaller items such as cables
that are susceptible to damage. If you are carrying instruments
to another country ensure you have documentation to
indicate what the instrument is, what it will be used for and
to whom it belongs. Custom regulations may need checking in
advance and you may be required to demonstrate how the
instrument works. Advance planning, and possibly
permission, will be necessary for any instrument that under
X-ray looks like a gun (as some detectors do) or contains
radioactive material (e.g. gamma-ray spectrometer and
portable XRF).
11.3 Correlation with other data sets
The geophysical data will often need to be correlated with
geological and, in some cases, topographical data. This is best
done when the measurement grid is set up. If appropriate to
the size and type of survey, consider incorporating each data
set into a Geographic Information System (GIS) that will allow
appropriate display of each set of data and will let you look for
