About the bones and some things we did with them

The finds and ceramics from Aakre have already been briefly introduced. Recently, our preliminary osteological analysis was finished and we would like to share some information. You may think that the archaeology bone labs look similar to the ones seen on TV in all of those crime-related shows. The truth is that we do not have that much fancy equipment, but nevertheless, archaeologists do have enough of space, good light conditions, magnifying glasses, calipers and scales that will work just as fine as all of the expensive machinery from the TV-labs.

Of documentation and analysis methods

Luuhoidla panoraamvõte. Tegelikkuses on ruum küll väiksem kui sel fotol tundub, aga kolm inimest mahub siia töötama sellegipoolest.

Panorama of the bone depot in Tartu. The room is definitely smaller than the photo suggests, but three osteologists can nicely fit and work in there at the same time.

Inglismaal toimus luude analüüs selle ukse taga. Vedelike ja toidu manustamine ukse taga keelatud, piiranguid on ruumis veelgi.

The bone analysis in the UK took place behind this door. No food or liquids in there! The inside of the bone lab is rather similar to any other room with the same purpose.

We tried to be as accurate as possible when recording the location of the items and bones. That resulted in thousands of zip-lock bags. First, all of the small bags were opened and their contents washed (except those that were meant for further laboratory analysis and also packed in tin foil) and sorted (during the washing process we usually find several small stones that were first thought to be pottery shards or bones). Then we let the finds dry, the labels tidied and everything was repacked. All of the finds got numbered, listed and were put into tiny boxes. The boned were handled slightly differently.

Namely, we do not pack bones in tiny boxes any more as they do not have lids and even the slightest and most careful attempt to transport the large boxes containing the small boxes result in the bones ”jumping around” and losing their contexts. We do not write on the bones and on the commingled remains, there is nothing to write as they do not receive a number except the one that refers to the site*. We decided that all of the bones will remain inside their zip-lock bags with their context labels given on-site. As every single little bone piece was to be mentioned in the ultimate ”list of bones”, we had to think of a recording system that would make the retrieval of all the mentioned fragments as easy as possible. Therefore we left the small bags with bones in larger bags with date-stamps (the date of their excavation) and numbers 1-16. Every small bag inside the large one also bears a number, similar to the index in the finds’ list. Altogether, there were 850 of these small labelled zip-lock bags that contained bones.

Viimane kotike, kus on näha poolikut piimahammast, numbri- ja kontekstisilti. Teisel fotol on üks keskmine luukilluke nihikuga. Selliste kohta pole muud öelda, kui ''määramata toruluu katke''.

A typical bone fragment from Aakre, a caliper for scale and note the bubble-wrap that covers the bone-lab tables in the UK. All we can say about these kind of bones is ”fragment of a long bone”.

2015-03-27 16.04.54

The last bag. You can see half of a deciduous tooth, number and the context label inside the bag that is placed on an important piece of lab equipment – a kitchen scale. 

Opening and closing these 850 zip-lock bags and adding the small labels in addition to the analysis was rather time-consuming. Nevertheless, the additional work was justified after we were able to generate plans of the excavation area with different bones depicted with ease. As the bones without exact GPS-coordinates (i.e. those that were found while sieving and have a whole area of possible origin) have not been added on the plans yet, we can only share plans that depict merely some of the bone distribution.

põlenud ja põlemata

Cremated (black dot) and inhumed (blue dot) bones with GPS-coordinates. Can you spot which are the empty areas and which are the large stones?

Bone weight

In the weighing process of the individual bones we used regular kitchen scales, whereas the one in Tartu can weigh everything heavier than 2 grams and the one used in the UK was able to spot differences of only one gram. In order to be consisted, we marked for most of the extra small bones that they were lighter than 2 grams, even though most of them were probably even lighter than a gram. Therefore we d not know the exact weight of all the bones, but the weight is ca 2100 grams which includes all of the bones – cremated, inhumed, animals and humans. That is not much, definitely less than the weight of a skeleton of an adult (even cremated) individual. These 2100 grams contained the remains of at least fourteen individuals and lots of animals!

These at least 14 individuals

The identification of individuals based on fragmented and commingled bones is usually done by counting recurrent bone fragments. If there are paired bones involved, it would be good to determine both the bone and its side, but that is rare for material as fragmented as the on from Aakre. As a great joy for osteologists, some of the bones preserve better than the others and they also have a very distinct looks, one of them is the petrous portion of the temporal bone (i.e. part of earhole from inside the skull).

Üks parempoolne kõrvaauk seestpoolt.

A right earhole, view from inside the skull or more scientifically, petrous portion of the right temporal bone.

Even this time, the minimum number of individuals whose remains were found from the tarand was determined by the count of recurring fragments of petrous portions of the temporal bone. It is called the minimum number because as long as we cannot divide all of the bone fragments properly between the individuals, there can always be an individual who is represented in the commingled bones, but that individual’s ”most popular recurring bone fragment” (in Aakre’s case the petrous portion of the temporal bone) had not survived. Altogether we found petrous portions from eleven different individuals and of these eleven, five had signs of having been in fire.

Based on the eleven temporal bone fragments, there were at least nine adult-sized individuals, a child and a fetus among the buried. The fetus had died around mid-pregnancy (other bones of a fetus aged 16-24 weeks were found as well) probably referring to a miscarriage. Some of these fetal bones should be sent for radiocarbon dating to find out when the unfortunate event happened. There is not much that can be said about the exact age or sex of the found adults. There were a few rather robust and manly bones, but as there were no recurring fragments, we can only state that there was at least one man buried in our excavated area. The presence of at least one man could have been assumed anyway, but it is good to know that for certain, especially in the case of bones fragmented to such extent.

Määramata toruluu katke. Põlemata.

Fragment of an unidentified long bone, inhumed.

So far we have spoken of eleven temporal bone fragments, although we have stated that there were at least fourteen individuals in the tarand. The additional three individuals were three kids aged 1-5 years, identified by upper central incisors. As we had no petrous portions of children of that age range, then the presence of these teeth should add three individuals to the minimum number. Saying ”should add” instead of ”adds” because as we were dealing with deciduous teeth, there may be a chance that the tooth loss was natural (as it usually is the case among preschoolers) and the teeth were simply disposed of into the grave. Nevertheless, as the tooth roots were intact and undamaged, the teeth were probably not wiggling yet.

We are hoping to know more about the minimum number of the buried after we have added all of the boned on the plans and had some time to analyse all of that. Until then we can guess safely that in the excavated tarand we had five inhumed adult individuals (among them one man), a fetus and three children aged 1-5 years and four at least partially cremated adults and a child.

Cremated or inhumed?

As you may have guessed, we had both cremated and not cremated bones. At first, it seems that the quantity of cremated and inhumed bones was rather equal, but we have not been looking very deeply into that yet. Generally, even the cremated bones were not very densely cremated, mostly merely sooted that refers to a cremation pit where oxygen is not freely available. The temperature affecting the bones from Aakre rarely exceeded 800 degrees (Celcius!).

Luukribalad kottides.

Bones in the bags, larger ”excavation day” bags in the background.

Animal bones were mostly not cremated. Considering that most of the animal bones belonged to small rodents who had been trapped or simply died in between the grave stones, it would be very strange if these bones were cremated.

What other kind of bones we had?

Excavating stone graves, especially the Iron Age ones, one may suspect that people have treated different body parts in different ways and with versatile rites. This time, we have bones of all of the body parts. Although, some of the bones are definitely underrepresented, we do not have any reason to believe (yet!) that the burial of some body parts were preferred or some were treated otherwise particularly.

There were teeth, altogether we had fragments of 83 human teeth. All of them were properly taken care of as is rather common for Iron Age populations – only two of the teeth had dental calculus and six had carious lesions.

We have not gone through the animal bones. We have mostly collected mandibles of small rodents that were present in almost all of the excavated layers and contexts. The top layers had some hare heel bones and horse footbones in them and the lowermost layers contained at least one cattle bone (the one we sent to Belfast for radiocarbon dating). We definitely have some old animal bones from the usage time of the grave, but there are quite a lot of new rodent additions.

What next?

We still have to work with the spreadsheets and get the all of the info properly on the plans. We also hopefully have a week of excavations during this summer to finish the tarand as we still have a few centimeters to go in some of the areas. Also, we would love to send more bones off for radiocarbon dating and get more isotope analysis results to see what they ate and when they died. Yes, we still have quite a lot to do.

Inim- ja loomaluukotike, mis sõitsid Belfasti dateerimisele ning isotoopanalüüsile.

Human and animal bone that we shipped off to Belfast for radiocarbon dating and isotope analysis. 

We will write about the results of radiocarbon dating and isotope analysis quite soon.

*In the University of Tartu all of the archaeological finds have two numbers written on them: first, the site/excavation number and then an index referring to the item’s queue in the excavation’s list of finds. E.g. in Aakre, the first item has TÜ 2410:1 written on it.

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