Message #250:
From: AzTeC SW Archaeology SIG
To:   "'Matthias Giessler'" 
Subject: Wood Sourcing Physical Methods And Resource Depletion
Date: Mon, 07 Jul 1997 10:37:36 -0700


From: 	Brian Kenny 

I attended an archaeology lecture of the Colorado Archaeological Society
in Cortez CO on July 3rd.  Dylan Schwindt  
presented an highly interesting and significant report on the chemical
and physical methods of wood sourcing.  Mr Schwindt provided an abstract
of his paper (reproduced below):

Tree Chemistry: A New Method for Addressing Ancient Resource Depletion

A Wood Sourcing Study of Utah Juniper (Juniperus osteosperma) Trees
Growing in Sand Canyon, Southwestern Colorado

by Dylan Schwindt

Summary
Can the chemistry of roof beams recovered from archaeological sites be
employed to determine wood sources used by ancient people?  This
research takes the first step toward answering this question by
identifying variations in the chemical composition of modern trees in a
small area of southwestern Colorado.  Further research into sourcing
construction timbers in archaeological sites appears promising, and may
help archaeologists determine whether resource depletion contributed to
the final Pueblo abandonment of the Four Corners area around AD 1300.

Abstract
The objective of this research is to evaluate variation in the elemental
composition of Juniperus osteosperma sapwood growing on different
sandstone substrates.  This will aid in assessing the feasibility of
tracing Ancestal Puebloan Juniperus construction beams and Juniperus
fuelwood in the Sand Canyon locality to their harvesting sites.  Ten
samples of Juniperus osteosperma sapwood, two samples of soil, and two
samples of bedrock were collected on each of four different types of
sandstone substrates present at Sand Canyon in southwestern Colorado. 
Flame Atomic Absorption Spectroscopy (FAAS) and Flame Atomic Emission
Spectroscopy (FAES) were employed to analyze the concentrations in parts
per million (ppm) of six elements ( Ba, Ca, Mg, Mn, Sr, Zn ) in all
samples.  Discriminant analysis of these data suggest that trees growing
in the four locations tested can be differentiated with varying success
rates for different formations.  Analysis of soil and bedrock samples
suggest that these differences are likely to be caused by variations in
substrate.  These results indicate that further research into the
sourcing of construction timbers in archaeological sites appears
promising.