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Not as you thought: The most significant archaeological work is in the lab and not at the dig…

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Many people ask us, what kind of processing do we do on our material before publishing – and why does it take so long? For a quick answer, take a look at the photo below – it tells us a little about the donkeywork behind the processing of artifacts. If you’d like to hear more about the behind-the-scenes work in our project, read on.

Table in the archaeology lab with thousands of pottery shards laid out on it in rows

Thousands of bowl rims from the Byzantine period, of the Fine Byzantine Ware type – Form 1, Variant B/D

As opposed to salvage excavations, in an academic excavation the main core of the archaeological work is carried out in the lab and not in the field. The average yearly excavation work consists of around a month of excavation on site; the remainder of the year is taken up with studying and processing the finds in the lab. In the case of the finds from the Temple Mount Sifting Project, the challenge of processing the material is more difficult since the artifacts were not uncovered in-situ, and hence we need to apply complex statistical calculations in our research with the aim of reconstructing the original context of the more frequent finds.

The collections of artifacts from the Temple Mount sifting process arrive at the lab as a kind of enormous jigsaw puzzle with hundreds of thousands of pieces. Initial sorting is carried out at the sifting site, where the finds are sorted by material (earthenware, metal, animal bones, etc.) and by major categories of find (pottery vessels’ rims, oil lamps, marble floor tiles, opus sectile floor tiles, sawn bones, burnt bones, etc). In the laboratory, the material undergoes further sorting, first by dating into time periods and then into classes of artifact (e.g. bowls, jars, cooking vessels, jugs, juglets etc.). In the next stage, the resolution of the sorting increases: each class is sorted into types (using criteria of shape, material, style, decoration etc.).  This stage constitutes the majority of the sorting work, and is termed “typology”. The next stage, as seen in the above photograph, entails sorting artifacts of each type by the area in which they were found in the soil dumps removed from the Temple Mount.

In a regular archaeological excavation that is carried out on site, archaeologists study and publish the finds in respect to the areas in which they were found, and the study of certain areas, and sometime even categories of artifacts, may be postponed to a later stage. In our case we cannot do this since the study of all the artifacts is inter-related – as in our analogy of the jigsaw puzzle. All the artifacts must be sorted first in order to understand the rest of the artifacts. This is because different types of artifact from the various time periods represented are scattered over the different parts of the dump. However, they are not scattered uniformly like a well-mixed salad, but are distributed over the different parts of the dump in varying patterns of concentration. What’s interesting here is that types of artifact that apparently came from the same original context are scattered in similar patterns – that is to say, they have similar statistical distributions over the areas of the dump. For this reason, where the dating or identity of some types of artifact is unknown, this information can be deduced from a different type of artifact displaying a sufficiently similar distribution in the dumps (whereas in a conventional excavation, this information may be deduced from other, identifiable, artifacts found in the immediate vicinity). The project has developed a novel statistical method which helps deduce the original context of artifacts extracted from dumps and earth fills.

For the statistical analysis of the pottery, we chose to sample only shards from rims of vessels. A vessel’s rim is its most indicative part in identifying the vessel type. In a regular dig, archaeologists generally discard most shards, retaining only those which were part of the vessel’s rim, although whole vessels may also be found, but usually they are significantly fewer than the pot shards. In our case, our pottery finds consist only of broken parts of vessels, shards. We have reached the stage where we have finally finished the typological sorting of the majority of the pottery shards, and have started to count and record them in a database as a precursor to the initial statistical analysis. To this end, we have enrolled volunteers (and here we acknowledge the great help given by Sari Sapir, Michael Swirsky and Dr. Ron Beals!). Since we’re talking here about a fantastic opportunity to learn about Jerusalem’s pottery history through the ages and get some great hands-on experience on the subject, we offered the task to archaeology students, at which point Keren Schwartzman, a 2nd year archaeology and chemistry student at the Hebrew University, jumped at the chance. This work includes sorting shards of each type by the dump section in which they were found, and then counting the groups and entering the data into the database. To this data are added measurements taken from samples of pot shards from each type, such as: maximum diameter, average circumference conservation percentage and more.

Exciting, no? Ok, so we got a little carried away… but ladies and gentlemen, this is archaeology! It’s fun to dig, but to reach significant conclusions we need to invest in exacting and thorough research. We’re dealing here with little kettle knobs, because each kettle has its own definitive kind of knob. When we start to understand the significance of each kind of knob, the slant of a rim, the thickness of a vessel wall, the hardness of the earthenware material, decorations and other properties, then business starts to get really interesting, and we can start to throw new light on the history of Jerusalem.

Researcher inspecting a pottery shard in front of a table containing heaps of pottery shards.

Haggai Cohen, Researchers Manager, in deep study of the shard he holds…

Check Out our New Methodology Page

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We are frequently asked about the archaeological significance of our finds which were not found in their original context, and other questions about our unique methodology. For this we have created a new page (see website menu above) in which we clarify and explain our unique methods for retrieving and studying the Sifting Project finds.

Reconstructing the Context of Our Frequent Finds

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When we began transferring the mounds of Temple Mount material from the Kidron Valley dump to the Tzurim Valley National Park, we divided the dump into various areas.  We suspected that the order of the removal of the earth from the Temple Mount and the location of its dumping may correlate somehow to the way it was excavated.  We also separated the marginal areas of the material from the internal areas that had not been disturbed by the other illicit dumps in the Kidron Valley. The Temple Mount material was eventually divided to 11 areas that were removed separately.

Early in the Sifting Project, we already noticed that there were differences in the frequencies of certain types of finds from different areas. Moreover, similar finds, and sometimes fragments of the same object, were discovered within short periods of time. This suggested that these similar objects were originally next to each other. But the full significance and value of dividing the material at the dump into different areas was discovered only last summer, during the processing of quantitative data for the Third Preliminary Report which we recently published. We found that artifacts which we assume to be from the same context were also distributed in a similar manner. Another example is that we found that artifacts which can be identified with the Horses of the Crusader era Templar Knights were distributed in a similar way among the dump areas.

We concluded from this that we can define a statistical distribution “fingerprint” for each artifact type.  Artifacts that have a similar “fingerprint” may have originated from the same context. The statistical technique for finding such relationships and verifying their statistical significance is called Cluster Analysis.We will not go into a detailed explanation of this technique, but we can foresee that at the completion of the classification and sorting process of all the different types of finds that we have, we will be able to apply this technique on a unified data table of all the finds.  The results of this analysis will show clusters of finds having similar distributions. These clusters may also represent a similar context of the finds within them. Currently, we are still investigating the application and implication of this method.  Only after finishing the classification and sorting process, will we be able to create a full data table that will be adequate for such an analysis, and then we will be capable of fully estimating the value of this method. If we are able to achieve valuable information from this type of analysis, it will be a substantial innovation in archaeological method and theory research which could also be applied by other archaeologists who focus their research on excavations of fillings or site surveys.

We can illustrate this idea using the following example:
Suppose we prepare a salad using four vegetables and two cutting boards. On one board we cut cucumbers and tomatoes, and on the other carrots and onions. The vegetables on each cutting board are thoroughly mixed and placed in a large bowl. They are then lightly tossed in the bowl. Such a mixture will result in the vegetables being scattered unevenly throughout the salad. It can be assumed that the distribution of vegetables that we cut and mixed on each board will show a similar distribution within each of the various areas of the salad. Let’s further illustrate this with the following table:

Board 1: 21 cucumber pieces and 11 tomato pieces (32 total pieces)

Board 2: 6 onion pieces and 12 carrot pieces (18 total pieces)

Mix the cut vegetables well on each cutting board and then combine them together in a large bowl. The vegetables in the large bowl are lightly tossed and then its contents are divided equally into 4 smaller bowls. This procedure may yield the following data table:

Salad Uneven Distribution Table

It can be seen in the table that the distributions of the carrots and the onions within each bowl are similar, but differ from the distributions of the cucumber and the tomatoes in the corresponding bowl and vice versa.

This is the value of “cluster analysis.”  By observing the percentages of various types of finds within each area, we may be able to determine which types of finds originated from the same context.

Analyzing Prevalent Finds from the Temple Mount Using Control Groups

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      One of the major tasks in our project is to develop ways of overcoming the absence of an archaeological context for the artifacts.  A common method to address this obstacle is to date and study artifacts using typology.  That is, using the knowledge of frequent finds from other archaeological sites – parallel finds that were recovered with a clear context – to assume that our finds should also be related to such a context.  Typology means that certain traits (technological and stylistic) tend to appear together in a repetitive pattern, which, because of standardization rules, creates types.  Types tend to appear in many parallel sites in a certain time span.

 The prevalence of out-of-context artifacts in Archaeological Research

  In most archaeological excavations, the majority of the artifacts are not found in a primary context. Often, most of the features excavated are not “sealed” loci or layers of destruction in which the artifacts were preserved in their primary form of deposition.  Rather, in most cases, the excavated features are late fills. These late fills can contain out-of-context artifacts from various periods up to the time of the fill, or stratified accumulations of debris that came from either a natural wash or from human-earth maneuvers. Nevertheless, archaeologists still carefully excavate such features. These features can still include artifacts that can be identified and dated; thus shedding light on the features, the site, the culture, and the period themselves.

  Archaeological researchers also make extensive use of archaeological surveys, which are based on artifacts collected from the topsoil of archaeological sites.  The topsoil usually contains a good sample of artifacts from all periods that the site was occupied.  The reason topsoil can be so highly indicative is likely due to repeated plowing that occurred at the sites during the various time periods.  By sampling these artifacts, we can get a general idea about the times the site was occupied and the type of material culture that was in use during those periods.

The Need for Control Groups

  In many ways, the artifacts recovered from the earth of the temple mount could be studied similarly to those from an archaeological survey.  Temple Mount has never really been excavated before, and we do not currently have records of internal prevalent archaeological artifacts.  As a result, our efforts with the Temple Mount debris could truly start to provide a substantial amount of original information from these artifacts. The issue here, however, is that in order to discover meaningful information from the distribution of the various types of finds it is not enough just to quantify them, but rather to compare them to other finds that were recovered from similar samples.  For example, in the study of the fauna remains, we have found several foxes.  In order to find out if the amount discovered is actually significant, we first need to know what would be considered an average amount of fox remains in the debris of other locations in Jerusalem.

    Since we are recovering the artifacts using a unique methodology (wet sifting), the distribution of the various types identified cannot be compared to the distribution of artifacts that were published from other excavations. Instead, the proper way to achieve this task is to create control groups by sampling debris from various areas in Jerusalem.  This debris should be as similar as possible to the debris from the Temple Mount by the site formation processes it went through.  The earth from these samples should then be sifted and sorted in the exact same ways the earth from the Temple Mount is treated.  This methodology of using statistical control groups is common in most scientific researches, but in archaeology, unfortunately, it is rarely used.

Sampling Jerusalem

  For this reason, we have begun sampling debris from various sites in Jerusalem.  Our first step was to sample debris from excavations that were currently being conducted.  We have already sampled debris from Eilat Mazar’s excavation in the City of David, Yechiel Selinger’s excavation in the slopes of the western hill, and from Shimon Gibson’s and James Tabor’s excavation near Zion’s gate, just outside the Ottoman Old City walls.  The remains from these sites contain a mixture of artifacts from various periods. Most notably in fact, is the latter example. It is a medieval fill that contains artifacts of a period span from the Iron Age II (First Temple period) until the Fatimid era (Early Arab period). This is a very similar fill to the one that blocked the Solomon’s Stables northern archways, and is now being sifted by us.

  In the near future, we also plan to transfer two more samples to the sifting site. The first is another fill from the Early Arab period, from Doron Ben-Ami excavation at the Givati parking lot, near the City of David.  The second sample will be taken from the Pa’amon Garden, a location containing archaeological debris dumped in the 1970’s during extensive excavations outside the Old City Western Wall, conducted by Magen Broshi.  We may decide in the future to sample even more locations, if necessary to increase the sampling level.

  The next step will be sifting and sorting these samples and then doing comparative statistical tests on the Temple Mount material.  Although much work lies ahead of us, we believe that this is the only way to attain meaningful innovative information from the prevalent finds of the Temple Mount debris.