Degradation ភាពរិចរិល Distinction ភាពខុសគ្នា Preservation ការពារ
Swamps, marshes, and bogs តំបន់វាលភក់ Mudslide ដីបាក់
Looms and spindles កីត្រល់តម្បាញ Deteriorate
កាន់តែពុកផុយទៅ
Quadruple បួនដង Harpoon ស្នរ
Bailers ម៉ាស៊ីនបូមទឹក Dorsal
fin ព្រុយខ្នងត្រី Miniature រូបមនុស្សតូចៗ
Figurine រូបចម្លាក់តូចៗ
The availability of archeological
evidence for study is dependent on the natural conditions in which the
archeological remains are found; certain types of natural conditions favor
preservation of organic substances and therefore lend themselves to sheltering
well-preserved organic remains, while other types of natural conditions lead to
the degradation or destruction of
organic remains that may have existed. An important distinction in land archeology can be made
between dryland and wetland archeological sites. The vast majority of sites are
dry sites, which means that the moisture content of the material enveloping the
archeological evidence is low and preservation
of the organic material as a result is quite poor. Wetland archeological sites
are sites such as those found in lakes, swamps,
marshes, and bogs; in these wetland archeological sites, organic
materials are effectively sealed in an environment that is airless and wet and
that therefore tends to foster preservation.
It has been estimated that on a wet
archeological site often 90 percent of the finds are organic. This is the case,
however, only when the site has been more or less permanently waterlogged up to
the time of excavation; if a wet site has dried out periodically, perhaps
seasonally, decomposition of the organic material has most likely taken place.
Organic material such as textiles, leather, basketry, wood, and plant remains
of all kinds tends to be well preserved in permanently waterlogged sites, while
little or none of this type of organic material would survive in dryland
archeological sites or in wetland sites that have from time to time dried out.
For this reason, archeologists have been focusing more on wet sites, which are
proving to be rich sources of evidence about the lifestyles and activities of
past human cultures.
A serious problem with
archeological finds in waterlogged environments is that the organic finds, and
wood in particular, deteriorate
rapidly when they are removed from the wet environment and begin to dry out. It
is therefore important that organic finds be kept wet until they can be treated
in a laboratory; the need for extraordinary measures to preserve organic finds
taken from wetland environments in part explains the huge cost of wetland
archeology, which has been estimated to be quadruple the cost of dryland
archeology.
One wetland site that has produced
extraordinary finds is the Ozette site, on the northwest coast of the United
States in the state of Washington. Around 1750, a huge mudslide that resulted from the seasonal
swelling of an underground stream completely covered sections of a whaling
village located there. Memories of the village were kept alive by descendants
of the surviving inhabitants of the village in their traditional stories, and
an archeological excavation of the site was organized. The mud was removed from
the site, and a number of well-preserved cedarwood houses were uncovered,
complete with carved panels painted with animal designs, hearths, and benches
for sleeping. More than 50,000 artifacts in excellent condition were found,
including woven material such as baskets and mats, equipment for weaving such
as looms and spindles, hunting
equipment such as bows and harpoons,
fishing equipment such as hooks and rakes, equipment used for water
transportation such as canoe paddles and bailers,
containers such as wooden boxes and bowls, and decorative items such as a huge
block of cedar carved in the shape of the dorsal
fin of a whale and miniature
carved figurines.
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