Neolithic archaeology; birch bark ; bow case; object conservation; ice patch; freeze-drying
Klügl Johanna, Di Pietro Giovanna (2021), The interaction of water with archaeological and ethnographic birch bark and its effects on swelling, shrinkage and deformations, in Heritage Science
, 9(3), 1-15.
Junkmanns Jürgen, Klügl Johanna, Schoch Werner, Di Pietro Giovanna, Hafner Albert (2019), Neolithic and Bronze Age Archery Equipment from Alpine Ice-Patches: A Review on Components, Construction Techniques and Functionality, in Journal of Neolithic Archaeology
, 21, 283-314.
Klügl J., Hafner A., Di Pietro G. (2017), Towards a description of the degradation of archaeological birch bark
, International Council of Museums, Paris.
Klügl Johanna, Hafner Albert, Di Pietro Giovanna, On the rolling and plasticization of birch bark, in 14th ICOM-CC Wet Organic Archaeological Materials (WOAM) Working Group Conference
, Portsmouth UKArchetype, London.
Maximum moisture content of contemporary birch bark
||Kluegl, Johanna; Di Pietro, Giovanna
|Persistent Identifier (PID)
Data accompanying the article published on the Icom-CC proceedings 2017 Copenhagen.
This project aims to define long-term conservation strategies for this unique, earliest example of a Neolithic bow case and to shed light on its historical significance by investigating how it was manufactured and used. The bow case, dating from around 2800 B.C., was found in 2003 protruding from an ice patch at the Schnidejoch Pass in the Bernese Alps, Switzerland. It is an archaeological object of outstanding value, since it is the only existing bow case from prehistoric Europe and it is the only Neolithic birch bark container to be built in this way. The Schnidejoch bow case poses two major challenges: firstly, it is unique and can therefore only be inserted into the archaeological context by comparing it with later dated bow cases; secondly, it is an archaeological object made of a material whose degradation process is as yet unknown and it is unclear how it should be preserved.The main body of the bow case, found immersed in melted ice, is stored frozen at -20 °C. At the moment it is the highlight of the Bern History Museum “The Pile Dwellers” exhibition but we know that transport and handling in frozen state can cause uncontrolled surface drying and formation of ice crystals. Our project, situated at the intersection between the science of object conservation and archaeology, aims at determining if and how the bow case can be dried to ensure long-term preservation and access and at expanding our archaeological understanding of this exceptional object.The two disciplines will collaborate to gain knowledge about the technology of the bow case. The bow case will be thawed in a controlled manner and secured in a form fitted encapsulating support to allow analysis of the construction and taking of samples. The construction will be investigated with high-resolution CT images and structured-light 3D scanning to build a complete 3D model. To supply details of the function of the bow case and examine the hypothesis that it was a common, rather than an exclusive piece of equipment in the Neolithic era, we propose to compare the bow case with Neolithic quivers, with later cases, and finally carry out experiments on reconstructed replicas to test its use. This intensive study will give new insights into prehistoric bow equipment and the comparative analysis of ethnographic materials from historical bow hunters will advance our understanding of the technology, the use and the maintenance of one of the earliest weapons of mankind.The samples of the bow case will be investigated with electron microscopy techniques (ESEM, SEM and TEM) to understand the micro-structure of the birch bark cells and their state of preservation. To define a range of possible birch bark degradation patterns these investigations will be repeated on archaeological samples of ice-logged birch bark from Lendbreen (Norway) and water-logged birch bark from Moosseedorf (Switzerland). These results, together with precise measurement of the water content at different temperatures above and below zero with a Mcbain-Bakr Quartz balance and with classical measurements of maximum water content and basic density, will allow us to make a prognosis on the magnitude of the risk of cell wall collapse during drying. The actual reaction of birch bark to drying without a previous consolidation will be examined both microscopically and macroscopically. Microscopically ESEM and Freeze-drying light microscopy will be used. Macroscopically 3D scanning will be employed to investigate eventual delaminations and cracks during drying of ice-logged archaeological larger samples donated to the project for research purposes. This range of investigations will allow us to forecast the consequences of the two drying procedures for ice-logged and water-logged birch bark objects and provide recommendations not only for the bow case but for a much wider range of objects. The Archaeological Service of the Canton of Bern, custodian of the bow case, will make the bow case available to the project and is committed to funding its restoration following the recommendations.