The Importance of Archaeological Conservation

Wednesday, October 14, 2020
Author: 
Terry Williams, QAR Conservator

 

The headlines read:

Gold Jewelry and Artifacts Found in Two Bronze Age Tombs in Greece
Archaeology News, Dec 26, 2019

Archaeologists Unearth Norse-Period Hall in Scotland
Science News Aug 9, 2019

Pirate Ship Found off the Coast of North Carolina
1997

 

Now what?! The next actions taken can mean the difference between a successful excavation or the loss of valuable historical artifacts and information. This is a very considered step; the cost of conservation and length of time to conserve an object may dwarf the original cost of the exploration and excavation. A day to lift an anchor from the seabed – 10 years to fully conserve it in the lab. As hard as it may be to believe, sometimes it is better to leave the site alone altogether.

Delicate hot water bottle recovered from the cistern at the Thomas Wolfe House.Archaeology, by its very nature, is the investigation of decayed remains. Time and environment often wear away all but the hardiest of objects. During excavation, a careful eye is necessary to see any sign of the more fragile objects that may yet survive. The American Institute of Conservation defines archaeological conservation as “the profession devoted to the preservation of objects, structures, and sites that constitute the archaeological record. These materials are primary resources for understanding and interpreting the past.” Conservation steps often begin on site; for example, delicate finds may need to be protected from further damage by shoring up their environment as excavation continues. In a maritime environment, recovered objects must be kept wet to avoid crystallization of the salts and subsequent destruction of the artifact; if allowed to dry iron objects will shatter, and organic materials will turn to dust.

A platter from the Thomas Wolfe cistern, pieced backed together like a puzzle.Once taken to a lab, conservators undertake steps to stabilize the objects, as well as evaluate them for further treatment, ensuring priority goes to the most fragile, unique finds. As you can imagine, artifact treatments run the gamut from straight-forward and short-term to highly complex, multi-year processes. For example, ceramics are a hearty representation of the past. From a terrestrial site, once documented and cleaned, they are treated somewhat as a grand puzzle being reassembled to reflect their original form.

Conversely, artifacts from a marine site are often covered in concretion, a calcium carbonate/iron corrosion construction that hides any evidence of the objects inside. Picture this as a giant blob that has joined everything in its path together, cannons with pewter plates, copper straight pins with grenades. As a result, identification of these objects may be a total mystery at the onset and require further testing and micro-excavation to solve the puzzle. X-rays, like those used to diagnose a broken arm, will reveal metals (or voids where metals used to be) and sometimes evidence of wood or ceramics. This examination allows not only for prioritization but also starting points for concretion removal.

Conserved spoons made of different metals from the Thomas Wolfe cistern.Once removed from concretion, the conservator will choose from a wide variety of treatments depending on material type and condition. In general artifacts will need to go through some combination of desalination (removing salts and minerals stuck to the object), stabilization, dehydration and restoration. Just reading all that gives you an idea of how long that can take!

Archaeological conservators not only salvage history but investigate its very mechanics and materials. These dedicated professionals serve in a fascinating field – unlocking the mysteries of the past!

 

Image Credits:
Hinge from Reed Gold Mine (top photo)- image by NC Office of State Archaeology
Thomas Wolfe House artifacts- images by NC Office of State Archaeology