Archaeological Objects

Archaeological Artifacts and Sites
Objects

Archaeological Heritage Network
Objects Specialty Group

Packing, Shipping, and Transport
Storage
Treatment Techniques and Procedures

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Objects Specialty Group Conservation Wiki

ARCHAEOLOGICAL OBJECTS

Contributors: Jeremy Borrelli, Claudia Chemello, Kate Clothier, LeeAnn Barnes Gordon, Susanne Grieve, Ida Pohoriljakova, Taryn Ricciardelli, Julie Unruh
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Copyright 2025. The Archaeological Conservation Wiki pages are a publication of the Archaeological Heritage Network of the American Institute for Conservation. Publication does not endorse nor recommend any treatments, methods, or techniques described herein. This information is published as a convenience for the members of the Archaeological Heritage Network, and is intended to be used by conservators, museum professionals, and members of the public for educational purposes only. It is not designed to substitute for the consultation of a trained conservator.

The Archaeological Heritage Network welcomes suggestions for new content or changes to existing content to this wiki. Please contact the Archaeological Heritage Network with suggestions, or feel free to edit these pages yourself if you are already a registered wiki editor.

Cite this page: Archaeological Heritage Network. 2025. Archaeological Objects Wiki. American Institute for Conservation (AIC). Accessed January 21, 2025. https://www.conservation-wiki.com/wiki/Archaeological_Conservation

Field Procedures[edit | edit source]

Lifting and Block Excavation[edit | edit source]

[This section is under development.]

The term “lifting” refers to an archaeological excavation method in which the sediment matrix of an archaeological site is included during an artifact’s removal from its primary, in situ source ^[1]. The technique of lifting can be useful when an artifact is too fragile to be removed from its matrix without proper conservation techniques. Lifting is also beneficial if the tools for controlled conservation are not available on-site or are inadequate for a specific material type. In locations where artifacts undergo an extreme change in moisture content from their burial environment to an unprotected environment, block excavation is an especially important protective measure ^[2].

Conservators working in the trench to help excavate and stabilize finds before lifting. Courtesy Archaeological Exploration of Sardis (Harvard University)

Methodology[edit | edit source]

No matter what the site type, tools and storage preparations should be assembled before an artifact is lifted. Block excavations usually require more space than completely excavated artifacts, and sometimes also require more controlled storage conditions. The identification of artifacts in block excavation should be secondary to the proper removal of fragile material ^[1].

Terrestrial Sites[edit | edit source]

Before attempting to lift an artifact from its terrestrial site, the object should be isolated from the unit, leaving it as exposed as is possible, depending mostly on the artifact’s fragility. Terrestrial block excavations rely mostly on horizontal support slid underneath the artifact; however, whole vessels also rely on the accumulation of sediment inside the vessel for major structural support. To isolate an object for block excavation, measure the amount of matrix to be left around the artifact, making sure to leave a pedestal underneath for a horizontal support ^[2]. Once an artifact is exposed and undercut by a horizontal support system, there are three basic types of terrestrial, block excavation ^[1].

The first type of terrestrial block excavation relies on a rigid support system. These rigid support systems can be simple: using bandages dipped in plaster of Paris, or they can consist of backfilled plastic containers. Another rigid support system can be created by letting paraffin wax drip over the block to form a hard container-like surface ^[1]. The advantages of rigid support systems of this nature are that they are simple, cheap, and easy-to-use in the field environment. However, they work only in the simplest of contexts, where soil is neither too fine or too hard, and when the artifact is not subject to increased damage. If the artifact needs to be kept damp while being excavated, wet tissues can be applied before the rigid support system ^[2]. If an artifact is incredibly fragile, polyurethane foam can be used in between the block and a rigid support system of cardboard, so that the artifact may be inverted after excavation ^[1].

The second form of terrestrial lifting relies on a support system being directly applied to an object. This is not largely used, at adhesives can directly affect the artifact (see ^[1] example of a mosaic being lifted using cotton sheeting). The final type of terrestrial lifting is consolidation ^[1]. A synthetic consolidant ispoured onto an artifact, making it easier to remove the artifact from the ground. A consolidant should only be used when there is a conservator directly on-site, and only for specific types of materials.

Underwater Sites[edit | edit source]

The size of the artifact directly affects how an artifact is lifted from an underwater site. One method of lifting larger objects with their attached matrices requires the freezing of the surrounding water. The methodology is as follows:(a) A thermally insulated barrier is placed around the object. (b) Using adequate safety precautions, the barrier is infilled with dry ice and wrapped in more insulation. (c) Insulation is placed over the ice whilst the water freezes. (d) The barrier is removed and the frozen wedge levered from the ground. (e) The wedge is settled into a bed of vermiculite for support and insulation ^[1].
Smaller artifacts can be packed into a container containing the sedimentary underwater matrix.

Suggested Tools[edit | edit source]

Tools used by conservators while working in the trench to stabilize finds before lifting. Courtesy Archaeological Exploration of Sardis (Harvard University)

Large trowels
Small trowels
Brushes
Plastic stretch film (food wrap)
Aluminum foil
Horizontal supports (wooden sheets, corrugated plastic board, cardboard, etc.)
"Ace"-type stretch bandages or self-adherent bandages
Temporary consolidants (see volatile binding media)
Permanent consolidants such as a dilute polyvinyl acetate emulsion or an acrylic polymer
Droppers, squeeze bottles, or other containers and applicators for consolidants
Backing or facing materials such as cheesecloth
Plaster of Paris
Plastic containers of varying sizes
Spray bottle of water for dampening soil
Expandable polyurethane foam
Cardboard rings
Duct tape or masking tape for securing packaged block lifts
Insulation Materials

Adhesives for field conservation[edit | edit source]

[Contributions sought for this section, particularly for: adhesives in hot climates; alternatives for adhesives requiring solvents that are not locally available.]

Object packing, transport, and field storage[edit | edit source]

[Contributions sought for this section]

Field storage[edit | edit source]

[Contributions sought for this section]
Field storage may operate under special constraints, including a lack of access during the off-season (limiting pest management, the resetting of electrical equipment after outages, or the ability to address off-season leaks or other problems); a lack of reliable electricity (limiting the usefulness of dehumidifiers, HVAC units, or wifi-enabled dataloggers); and a lack of funding, time, and supervisory personnel for enacting container retrofits.

A poor storage environment can severely impact an object's viability for analysis. High temperatures accelerate molecular alteration, and relative humidities above 65% support mold contamination and physical damage by mold hyphae. A short list of techniques that have limited success after samples have been stored at high temperatures includes DNA sequencing, FTIR, certain GC-MS analyses, organic residue analysis, and ZooMS. A short list of analyses that can be invalidated by mold activity includes some archaeobotanical characterizations, dendrochronology, DNA sequencing, FTIR, GC-MS, micromorphology, certain optical microscopy, organic residue analysis, some osteoarchaeological characterizations, radiocarbon dating, stable isotope analysis, and ZooMS. ^[3]

Shipping containers as field storage[edit | edit source]

[Contributions sought for this section]
It is increasingly common for shipping containers to be repurposed as on-site storage depots for artifacts and samples on archaeological sites. Shipping containers are attractive from the field project point of view, as they are low-cost, ready-made, easily transportable structures that can be quickly outfitted with storage furniture. From the preventive conservation point of view, shipping containers lack adequate passive environmental control: in fact, due to the lack of insulation and ventilation, they can actually amplify poor environmental conditions.

Solar-powered ventilators and other purpose-built retrofit equipment is available from shipping container vendors and others in the industry. Unfortunately, both conservation and archaeology literature lack practical advice for retrofitting containers for improved passive environmental control, though a pilot study has been completed.^[4] A method of constructing shade cover has been published.^[5] Passive humidity control has been demonstrated to be possible, but with the caveats that the volume of buffer needed decreases available storage space, and the effectiveness has only been demonstrated over a two-month period.^[6] One trial found that passive ventilation as configured for the test had limited effect.^[7]

Additional topics[edit | edit source]

Archaeological illustration