A common theme in analyses of dating
techniques is the determination of a particular technique in a region at a time
as accurate or inaccurate. The most
apparent way of doing this is by using several techniques to date a single
artifact in combination with seriation. This
article is one such attempt, showing the degree to which tree-ring and
thermoluminescense show similar results.
The major reason this article was
written was to help alleviate the difficulty of finding accurate but rare
tree-ring datable artifacts to help date surrounding strata. Precise dates are important, especially in
relatively recent sites. The authors try
to show the degree to which thermoluminescense dating methods are similar in
accuracy to tree-ring dating methods.
Since there is only one possible date for the output of
thermoluminescense (unlike such problems as the ‘old wood’ problem in
radiocarbon dating), it is a good method for getting the ‘true’ date of an
artifact. The authors found a 40%
correlation rate between thermoluminescense dates and tree ring dates from the
same layer. Although I would not make a
claim of this being good, the authors do make such a claim. They also say that with further
thermoluminescense research, this number can be brought up much higher. In addition, doing similar studies on a much
wider array of sites can help to alleviate some of these differences even
further. This study has obvious
significance, as it applies to a wide area during a medium span of time.
One of the most complex and striking
questions regarding the early prehistory of the Southwest is the emergence and
dispersal of agriculture. Because of the
dry environment present in the Southwest, canals were a common and necessary
way to grow these plants. It is
therefore a reasonable expansion that dating the earliest canals should give a
rough estimation of some of the earliest agriculture. This line of thinking obviously breaks down
when one considers that it is far more difficult to find a hole than an
artifact, river erosion and the fact that early agriculture likely was
concentrated around rivers, and that there is only a very small percentage of
land that has been examined thoroughly in the Southwest. Still, knowing the dates of the earliest
canals that are known of can be a useful thing to know, as can be the pictures
of population growth that examining canal patterns across regions can show.
Dating canals can be extremely
tricky, as they seldom contain obviously datable material. Archaeomagnetism, however, has proven to be a
good method for dating these canals, at least where they have remained relatively
undisturbed. Although individual results
may go awry, the results can also be compared to a much larger master database
that helps to ensure the results.
Although it was not the goal of the authors to date the earliest or
trace development patterns, the authors show that archaeomagnetism is a good
method for determining the dates in which the canals were dug to within one
hundred years.
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