DESTRUCTIVEINVESTIGATIVE TECHNIQUES 137
Samples should only be collected if three basic criteria
can be satisfied:
1 There should be evidence that the sample will
contain traces which will provide valuable informa-
tion concerning the past. This is best checked by
examination of a pilot sample either on site or in
the laboratory.
2 There must be a sound reason for collecting the
material. Specific questions should be asked, post-
excavation analysis is made easier if objectives are
clearly stated.
3 There should be a clear prospect that the material
will actually be studied. This should be established
by consultation with specialists before, or at an early
stage of the archaeological investigation. However,
important material should be sampled even if
no scientific programme has been pre-arranged: a
specialist can usually be found to work on material
of significance.These three criteria can best be satisfied if a clear
strategy is agreed between the archaeologist and relevant
specialists beforehand, or as soon as the problems
become apparent during excavation. It is important
to understand, however, that even after carrying out a
detailed examination a scientist may be unable to pro-
vide a simple unqualified statement. Every method of
examination has its own limitations. Often one analytical
method must be employed to examine one group of
phenomena and a second, quite distinct, method used
to examine other aspects of the same sample.
It may be useful to attempt to divide non-artefactual
or environmental archaeological remains into broad cat-
egories. For example:
- Economic– Environmental archaeology can make
considerable contributions to our understanding of
the economy of a site or period. At its simplest level
this may relate to what was eaten on the site. At a
more complex level the environmental information
can be used to reconstruct the contemporary agri-
cultural economy or used to illustrate differences
(such as social, religious or racial) across a site or
between sites. - Environmental– This refers to the sampling of
deposits that may yield information on the general
climatic, environmental or ecological conditions
prevailing on or near a site. With respect to under-
water sites, this may mean samples that can gen-
erate information about the formation of the site
or, perhaps, data on the chemical and physical
characteristics of the site and particular preserva-
tion conditions.- Behavioural – The biological remains contained
in certain contexts and/or their distribution across
a site can relate to various aspects of human
behaviour. At its most obvious, the threshing and
winnowing of cereal crops on submerged settle-
ments could produce recognizable patterns among
botanical assemblages. The practising of crafts or
commercial activities on board ship may also reveal
itself in characteristic groups of animal bone or
other materials on shipwreck sites. It may also
be possible to interpret the function of specific
areas or determine the original contents of containers.
- Behavioural – The biological remains contained
An important part of any archaeological investiga-
tion is stratigraphy: the study of the various sediments,
embedded structures and features that comprise the site’s
stratification (chapter 4). Apart from visual methods
of characterization it may be necessary to take samples
of the various layers present for laboratory analysis.
Sedimentology – looking at particle size and composition
through the depositional sequence – helps determine
the changes that have taken place over time (see column
sampling below).
The principles of radiocarbon and dendrochrono-
logical (tree-ring) dating have already been introduced as
the two main techniques of absolute dating (chapter 4).
There are many factors that critically affect how viable
samples are for particular types of dating analysis.Radiocarbon sampling: It is recommended that con-
tact should be made with a radiocarbon laboratory at
an early stage, if possible before any samples are taken. The
following points should be taken into account:- Never submit a radiocarbon sample unless the
archaeological problem it is intended to solve is
clearly identified. It may have nothing to do with
chronology. Dates well-related to the span and signi-
ficant events of site chronology should always be
sought. Do not be wooed by potential samples
simply because they are there. Always try to form an
opinion on the chances that a sample will actually
date the human activity or natural phenomenon for
which a date is sought. In most cases there is no abso-
lute certainty of association or contemporaneity. - Before taking a radiocarbon sample from an archae-
ological deposit, section or core, study the nature
of the deposit or layer and the stratigraphical con-
ditions (such as geological complications, pos-
sibilities of humic contamination from higher levels,
root penetration, visible animal activity from other
periods). - Collect more samples or a greater amount of
sample than required for one dating because a later