Geoscience Reference
In-Depth Information
13
Sampling
Angela L. Coe
13
Sampling can be a crucial part of a fi eld programme because
the samples, your fi eld notes and photographs are all that you
will have when you return from the fi eld. But all too often
sampling is rushed either because it is the last task completed
or because of the perceived need to cover a wide area within a
short time and extract material that is easily accessible. It is,
however, well worth spending some time collecting samples
and recording exactly where they are from, especially if you are
going to complete many hours of laboratory work on them.
Once collected, samples are often used for purposes other than
those for which they were originally intended. The key points
to consider when taking samples are:
•
What are the objectives and therefore how much and what
type of sample is required?
•
Is the sample representative?
•
What does the sampling resolution need to be?
•
Is the sample fresh and unweathered? (Unless of course the
study is about weathering.)
•
Does the sample need to be orientated?
•
Do I have the appropriate tools for the job?
•
Have I recorded exactly where the sample is from?
•
Is there a record of how the samples were collected, for
instance the tools used (to eliminate possible
contamination) and stratigraphic precision?
•
What are the conservation issues? Am I taking only what is
necessary, have I got the necessary permission and have I
considered the visual impact on the environment?
13.1 Selecting and labelling samples
The size and nature of the sample required depend on the
type of analyses that need to be performed. The appropriate
