The
list of tree-ring samples in the CDI database is
the total sample available to us from the Laboratory
of Tree-Ring Research, the Chaco Culture Museum,
and published sources. As with all dates,
there are important issues to be considered in
their interpretation and we refer the user to Jeff
Dean’s seminal publication “Independent
Dating in Archaeological Analysis,” for a
succinct discussion of issues with tree-ring dates.
In Chaco Canyon and in other locations
such as Aztec Ruin, reuse of wood is a particularly
important concern because of the long history of
stabilization work at many greathouses. For example,
two catastrophic events–the fall of Threatening
Rock into Pueblo Bonito in 1941 and the flooding
of Chetro Ketl in 1947–generated hundreds
of beams that were salvaged and later used during
stabilization activities in greathouses throughout
Chaco Canyon and the park-owned outliers. Additional
prehistoric samples were collected during stabilization
activities between 1940 and 1970 and stockpiled
for later reuse. Thus, dates of beams taken
from one site ultimately may have been mixed with
samples derived from other greathouses. Reused
prehistoric wood is also a problem at Aztec Ruins,
where many pieces were reused during stabilization
of the Aztec West Ruin. A few pieces at Aztec are
also documented as having origins in Mesa Verde
National Park, and a few pieces from Aztec were
used during stabilization at Cliff Palace.
Users should be aware that additional
provenience information is available for some samples
and not for others. Also, in a few rare cases
there are two data records listed for a single
tree ring sample in cases where a sample was analyzed
twice with divergent dates.
CDI is in the early stages of digitizing several
volumes of stabilization records from Chaco Culture
National Historical Park and we hope to make these
records available through our website in 2007.
Work on the wood database
continues as part of an overall NPS publication
on the Chaco and Aztec structural wood. For
specific questions about recent dates collected
during the Chaco Wood Project, contact Tom Windes
at windes@unm.edu.
Dean,
J.S. 1978. “Independent Dating in Archaeological
Analysis.” In: M.B. Schiffer, ed., Advances
in Archaeological Method and Theory, vol.
1. Academic Press, New York: 223-255.
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