Documenting a Shipwreck
Field Research: Excavation (Phase III)
Full excavation represents a substantial disturbance to the site, and is usually undertaken when a site is threatened with imminent destruction, or if the site is to be investigated as part of a specialized archaeological research project. During an excavation artifacts may be recovered and structural components of the wreck moved or unfastened, thus altering the site forever. The archaeologists' notes, drawings, and photographs will be all that remains to describe how the wreck looked before it was excavated. When done properly, fellow archaeologists and historians can be eyewitnesses to the excavation simply by reviewing the field archaeologists' records. In this way, it is possible for a single site to be studied by several parties.
Underwater archaeologists above water?
Carefully excavating a shipwrecked schooner
left high and dry by the slowly changing path
of a river, underwater archaeologists uncover
the contents of the ship's hold
A critical factor in excavation is the need to carefully record the three-dimensional location of all objects prior to recovery. An artifact's three-dimensional location is called its "provenience," and it can tell archaeologists volumes about a site. Though a study of its spatial relationship with other objects at the site, an artifact's provenience can help reveal its original placement or use on a site, relative age, function, etc. Disturbing this information by removing or even handling artifacts is akin to going into a crime scene before the detectives arrive, moving a critical piece of evidence, and thereby changing the outcome of the investigation. With only disrupted, destroyed, misleading, or missing evidence to guide them, neither detectives nor archaeologists can ever hope to learn the truth.
When archaeologists systematically remove artifacts from a site during a Phase III excavation, the work has only just begun. Objects that have spent decades--perhaps hundreds or thousands of years--beneath the waves need to be carefully treated when they are brought to the surface and exposed to the air. The process through which waterlogged artifacts are stabilized is called conservation.