Introduction to Archaeology: Class 5
Absolute dating: Tree rings and radiocarbon
Copyright Bruce Owen 2002
Two kinds of dating: relative and absolute
puts things in order, older to younger, without specifying dates in years;
we'll look at these later
gives ages in years.
In theory, this is better than relative dating, because we know both how old things are, and
can put them in order
Unfortunately, most “absolute” dating methods give slightly fuzzy dates (radiocarbon dates
are usually plus or minus 40 years or more), so sometimes we can get the order more
precisely by lower-tech, relative methods.
also, most absolute dating methods are expensive and involve sending samples to a lab and
waiting for the results
Some kinds of absolute dates:
(coins, dated inscriptions, etc.)
not as simple as you might think
for reasons that apply to all kinds of absolute dates, not just historical ones
the key is to have a clear understanding of archaeological
features, activities, and dates
Thomas throws in issues about associations while covering other things, but I think it is
important to deal with them head on, right away
and historical dates give us a clear, simple case in which to do it.
say we excavate a historical burial and find a coin in it dated 1827.
was the person buried in 1827?
First, we have to feel sure that the coin (or any absolute date) is truly
rest of the burial activity that we want to date
that is, that the coin got into the burial as part of the burial event, not some other time
we should try to rule out the possibility that the association is false due to
introduced artifacts after the event of interest
maybe the person was buried back in 1500
and in 1830, someone looking for treasure dug into the burial and accidentally dropped
the 1827 coin into it.
or in 1830 a gopher tunneled through the burial, and someone accidentally dropped the
1827 coin down the hole
we can try to rule out disturbance by carefully observing the soil and the positions of the
artifacts while excavating
that is, we can say "we looked carefully for evidence of rodent burrows but did not see
disturbance can introduce artifacts of any age