CONSERVATION

Principles

A. Site Conservation
2 – General principles

Giorgio Buccellati – August 2010, April 2011, May 2011

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1. Overview

There are general criteria that need to be spelled out as one approaches site conservation. They deal with the procedures through which one must oversee the overall process, from a definition of the goals and the specific planning that ensues to the nature of the recording, the follow-up monitoring and the final evaluation.

There are then two major mechanisms from which one must choose. The remains may be either affected by interventions aimed at altering the status of the document as originally found, or by the addition of elements aimed at protecting it without changing it.

In all of this, the figure of the conservator is crucial, as is their interaction with the excavators. Issues relating to their specific role and sensibilities are addressed.

For each of the points discussed, there is a link to the portion of the Urkesh Global Record where the data are given in accordance with the principles stated here.

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2. Criteria

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Goal definition

There are two main reasons why conservation goals ought to be spelled out clearly at the very start of excavations:

  1. in the first place, one should have a firm sense of priorities as one proceeds with the excavations: what can be sacrificed? What are the limitations on the strategy resulting from a specific conservation commitment? At what point should the direct involvement of the conservator be invoked?
  2. Just as importantly, any assessment of the conservation work that one will eventually be able to carry out, should be measured against the stated intent at the beginning of the work.


For an actual implementation of the goal definition one may look at the pertinent section on the palace walls.

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Planning

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Optimum

The insistence that conservation should be inscribed in the very strategy of excavation means, of course, that planning is of the essence. The point about strategy is that planning is not only important in terms of the technical efficiency of the preservation effort as such. Beyond that, planning is important because it impinges on the initial choices about excavation. Decisions about how to proceed, how extensive an exposure can be, even what tools to use, all of this should be coordinated, if not subordinated, to serious considerations about the risk of damage and the potential for avoiding it or at least ameliorating it if it should occur. Clearly, all of this is best handled by a professional conservator who should be included in the staff. This conservator should then have direct access to the excavators and be involved in the reasoning that goes into establishing the goals and procedures for the excavations.

In this respect, planning has to do with projections about feasibility on the basis of what knowledge we have before excavations take place.

On the practical level, planning must then extend of course to the allocation of resources. Besides personnel, one should include costs of equipment and supplies that are expected to be needed.

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Reality

In practice, it must be admitted that is seldom the case that planning might take place on a regular basis on the scale outlined above. On the one hand, the cost of a dedicated professional conservator who might be present for the entire duration of an excavation exceeds the financial range of most, if not all, projects.

But there is also the generally widespread attitude that conservation should be invoked in case of emergency, and that in any case it can safely be left for a moment subsequent to the excavation itself, when a new effort can be made to raise appropriate separate funding.

It is in order to counteract both aspects of the problem that it seems particularly important to insist on the need for the excavator to develop at least a specific sensitivity for conservation problems, and to apply it quite explicitly to the planning stages of each season’s work. Sensitivity is no surrogate for professional competence. But it can be very significant in coloring the details of the excavation plans, and to allow for potential problems to be identified in time for a professional conservator to address in a more limited period of time than for the entire duration of the season.

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Recording

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The internal record

Recording the procedures and the types of treatment follows the standards defined by the discipline, and it is the choice of the professional conservator to use whatever system seems most appropriate. This obviously entails, besides forms and standards, a photographic coverage before and after intervention. One goal of the record is to provide full information about the initial conditions, the way in which this has been affected by the treatment, the degree of reversibility one has aimed for, and so on.

The shape of this internal record is in function of the ease of the individual conservator. Standardization would be at the level of normal practice and of common sense, so that there may be continuity from one conservator to the next.

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The global record

Standardization, however, is more important than just for practical reasons (the continuity across seasons). It feeds into a global record of the excavation in an intellectual sense as well, as I argue with regard to the Urkesh Global Record. This means that every observation about the conservation of a given element will appear, or be referred top, in the particular entry that deals with that single element.

Thus the extensive evidence for conservation of the Palace walls and of the Temple Terrace is discussed in this section on SITE CONSERVATION in terms of the general approach to the system, but the specifics are given in full detail in relation to gthe individual features to which they apply, whether for the mudbrick walls of the Palace or the stone structures of the Temple Terrace.

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Monitoring

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The physical aspect/confrontation

Constant monitoring of the physical state of what is being preserved is obviously at the core of the issue. The very concept of preservation means to engage in a fight with events that take place over time. Once exposed, structures and other features in the open air are subject to constant danger from atmospheric elements, and thus a close check of their physical state will inform us about the success or failure of protective mechanisms that have been set in place, and alert us to to new dangers for which nothing has been arranged as yet.

What results from a regular confrontation with the physical dimension is in the first place a decisional moment, when concrete steps must be taken to countervene problems.

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The internal record

But there is obviously an obligation to record not only the preventive measures taken as a result of monitoring, but also any and all the observations that have been made in the course of the physical review. This is an internal record, that follows the conceptual and organizational criteria of the conservator, and may lead to an independent publication of the results.

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The global record

Within the Mozan system, it is indispensable that all observations resulting from monitoring be integrated, beyond the internal record of the conservator, within the framework of the overall system, in such a way as to reflect conservation concerns in relationship to each individual feature. The conceptual nature of the record as it is conceived within our website is particularly responsive to the notion of monitoring. Monitoring expects potential change. A given feature, once exposed, is not abandoned to itself. It must rather remain present to the attention of the archaeologists as excavations continue, and of site managers, if excavations have stopped.

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Evaluation

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Monitoring

Learning.

UNDER CONSTRUCTION

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Synthesis

UNDER CONSTRUCTION

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3. Mechanisms

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Overview of protective systems

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Superposition

While alteration mechanisms affect the very fabric of the structures, another approach to the protection of stationary structures is to superimpose external covers that shield them from harsh atmospheric agents, the three basic types being shelters, adherent covers and backfill.

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Broad base and localized shelters

When shelters are treated in the literature, it is generally understood that they are intended to roof an entire structure (see e.g., Agnew 2001, Palumbo 2001). But a qualification is needed once we introduce the alternative possibility of sheltering the individual components and not the whole of which these components are part.

I use the term “broad base” to refer to the large roofing projects.

I use instead the term “localized shelters” to refer to the system I developed in Mozan, where each wall is protected individually.

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Adherent covers

UNDER CONSTRUCTION

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Backfill

Backfilling consists of covering the exposed original document with dirt, reconstituting in some way the original situation before exposure. The main disadvantage is that the original can no longer be seen, either for the visitor or for monitoring (although the latter is possible by installing special devices).

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Alteration

Various interventions can be applied to outdoor elements, which affect the original document with varying degrees of intrusiveness.

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Superposition

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Localized shelters

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Goals

UNDER CONSTRUCTION

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Advantages

Theory – there is no discrimination.

Practical – walls are preserved during the process of excavation.

UNDER CONSTRUCTION

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Limitations

UNDER CONSTRUCTION

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Adherent covers

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Introduction

While localized shelters are so constructed as to allow some space between the ancient structure and the modern protective cover, there are occasions when a cover may be placed directly against the surfaces to be protected. The fact that the cover adheres to the original requires attention especially in two regards:

  1. first, care must be taken so that the cover does not damage what it is meant to protect simply by virtue of adhering to it too tightly;
  2. second, the distinction between the ancient and the modern must be made quite apparent, and must of course be reversible.

In Mozan, I have used this approach in two instances – draped covers on walls and strips on stone joints.

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Draped covers on walls

When a wall first exposed, it may be difficult to resort immediately to the localized shelter approach, or else the decision is made.

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Strips on stone joints

UNDER CONSTRUCTION

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Backfill

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Introduction

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The shield layer

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The soil layer

UNDER CONSTRUCTION

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Walls and beyond

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Brick and stone walls

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Brick and stone surfaces

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Accumulations

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Sections

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4. The conservator

UNDER CONSTRUCTION

For now, see conservator.

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Role

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Competence

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Tasks

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Interventions

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Monitoring

UNDER CONSTRUCTION

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