Ardsallagh 2-

 

Excavation report and more pictures at  http://www.m3motorway.ie/Archaeology/Section2/Ardsallagh2/

 

4 cremations in pottery vessels - Bronze Age - all adults

Osteological Analysis of Cremated Skeletal Remains from Ardsallagh Site 2 (A008/035),

M3 Clonee to North of Kells Motorway

Report prepared for Archaeological Consultancy Services Ltd

Patrick Randolph-Quinney BSc, PhD, MIAI, MIAPO

© ODK Resources 2006

ODK Resources, Kilcronagh Lodge, Kilmacow, Co. Kilkenny

Tel +353 87 969 6114 Fax +353 875 969 6114 odk@vodafone.ie

 

1. INTRODUCTION....................................................................................................3

2. MATERIALS AND PROCESS ..............................................................................3

3. REASONS FOR ANALYSIS AND SCOPE OF REPORTING ..........................3

4. IDENTIFICATION AND QUANTIFICATION OF SKELETAL MATERIAL

.......................................................................................................................................4

4.1 Introduction................................................................................................4

4.2 Results........................................................................................................5

5. TAPHONOMY.........................................................................................................5

5.1 Introduction................................................................................................5

5.2 Bone Fragmentation...................................................................................6

5.2 Colouration ................................................................................................7

6. HUMAN SKELETAL REMAINS..........................................................................8

6.1 Inventory ....................................................................................................8

6.2 Age at Death Assesment ............................................................................8

6.3 Sex Assesment ...........................................................................................9

6.4 Pathology .................................................................................................10

7. SUMMARY ............................................................................................................10

8. REFERENCES.......................................................................................................11

9. APPENDIX 1: CATALOGUE OF IDENTIFIABLE SPECIMENS.................11

 

1. Introduction

This report contains the results of the osteological analysis of cremated bone recovered at Ardsallagh, Co. Meath. Excavations were undertaken by Archaeological Consultancy Services (ACS) Ltd. as part of the M3 Clonee to North of Kells motorway development. Two small deposits of cremated bone were recovered from the site of Ardsallagh 2 (A008/034), both of which appeared to have been disturbed by post-depositional activity and active sub-aerial weathering.

ARD2/009 and ARD2/105 (Ardsallagh 2 samples # 189 and # 190) were recovered from the interior of pottery vessels (A008/034:009:001 and A008/034:105:009 respectively) of probable Bronze Age date. ARD2/001 was recovered from a cordoned urn for which the majority of the rim remained intact, but only 5% of the overall vessel structure. ARD2/002 was recovered from a food urn for which 75% of the rim remained intact, but only 5% of the sub-rim vessel structure.

The osteological analysis here presented aims to provide an identification and quantification of the cremated bone present, to differentiate (where possible) between animal and human remains, to assess taphonomic effects of thermal alteration and fragmentation, and to assess the age, sex and presence of any pathological conditions in the recovered skeletal material.

2. Materials and Process

The skeletal material was analysed in accordance with the standards recommended by the British Association for Biological Anthropology and Osteoarchaeology in conjunction with the Institute of Field Archaeologists. The skeletal material was analysed macroscopically and, where necessary, with the aid of light reflective microscopy (x50) for identification purposes. The skeletal material was compared against a reference collection of complete and fragmentary human and European domestic fauna.

All fragments >1 mm diameter were counted in order to assess the level of overall fragmentation amongst the assemblage. Fragments were divided into three size fractions (<10mm, 10-15mm, and >15mm diameter). The number of identifiable specimens (NISP) was recorded, with NISP fragments assigned to skeletal part (element) or taxonomic group. The material was weighed with a high-precision digital laboratory scale, with the mass recorded to the nearest 0.1 gram. An inventory of identifiable skeletal elements was recorded (Appendix 1).

3. Reasons for Analysis and Scope of Reporting
Osteological analysis was carried out to ascertain (where possible) the following:

• Identification and quantification of human bone

• Taxonomic groups present

• Surviving skeletal elements present

• Demographic assessment

• Pathological data

• Total weight of the bone recovered

• Degree of fragmentation

4. Identification and Quantification of Skeletal Material

4.1 Introduction

Cremation was the predominant rite for the disposal of the dead at various phases in Irish pre and proto-history, and up to and including the Hiberno-Norse period; consequently, burnt human bone is frequently encountered in archaeological deposits, in addition to often ubiquitous burnt or charred domestic animal bone waste.

Concentrations of burnt or calcined bone recovered from sites are often recorded as ‘cremations’, and this is generally a misnomer. Cremation refers to the burning pyre, or other pyrotechnical structure, and is part of a series of ritual formation processes within the mortuary rite, the nuances of which are still little understood. Cremation burial is the deliberate secondary treatment, selection, or manipulation of pyre debris and which may include a significant component of materials other than human bone, including pyre fuel, burnt or unburnt animal bone, soil clasts, and even artefactual remains.

Identification of elements of the human body retained in the pyre debris may give an insight into particular areas or portions of the body which may have been purposefully selected following firing, or taphonomic effects biases such as size-related winnowing of elements. Thus, in determining the nature of pyrotechnical event, accurate identification and quantification of the assemblage is critically important. Often, particularly if the bone fragments are very small (<5mm diameter), it is not possible to identify whether bone is categorically human or animal without recourse to histological analysis. However, a general assessment of the quantity of bone recovered may give an indication of the state of preservation of the associated feature in which the bone was interred or, if recovered from relatively undisturbed context, may provide valuable information regarding the cremation processes. This may relate not only to the efficiency of the pyrotechnology, but also to the collection and secondary deposition of bone after the firing was complete.

4.2 Results
The total amount of bone present in each sample was weighed and subsequently analysed for identifiable fragments. A total of 1327 fragments of burnt bone with a combined mass of 94.6 grams were analysed from the two contexts. The fragments were identified to skeletal part and taxonomic group where possible and assessed for surface modification. The overall weights, weight of identifiably human bone, and NISP and MNI values are tabulated in table 1 below. A full inventory of skeletal remains from each excavated sample can be found in Appendix 1.

Table 1. Quantification of burnt bone from Ardsallagh by site, showing total bone sample weight (in grams), weight of definitively human subset, percentage weight of human bone to total, number of identifiable specimens (NISP), and taxonomic groups represented.

Taxon key: Bos: Cattle; Homo: Human; Ovis: Sheep or Goat; Sus: Pig.

ARD2/009: No identifiable human fragments, definite or probable, were recovered from this sample. The sample was extremely small and highly fragmented (see section 5.2) rendering taxonomic or elemental identification impossible.

ARD2/105: This sample yielded two almost complete permanent mandibular premolar tooth roots, four fragments of fibular diaphyseal shaft, four fragments of cranial vault bone, four fragments of humeral diaphysis, a fragment of metatarsal diaphysis, and a rib shaft fragment. Thus portions of the cranial vault, gnathic, axial, and appendicular skeletons were recovered, suggesting no apparent bias in body portions within the bone assemblage. The presence of only one individual was indicated.

Overall, the small proportion of identifiable human fragments in the two samples may reflect a high degree of post-depositional disturbance to these contexts (see introduction) with concomitant levels of bone fragmentation (see section 5.2).

5. Taphonomy

5.1 Introduction
A variety of perimortem events and postmortem processes can be inferred from the study of bone colour, surface modification, fragment size, and shape. This investigation is generally referred to as taphonomy. When applied to archaeological assemblages of human or animal bone, taphonomic analysis proceeds from an assessment of surface modification. In general, these are divided into three areas: modification by physical agents, modification by non-human biological agents, and modification by humans; all three vectors can impact upon a cremated bone assemblage. Understanding the taphonomic history of a bone assemblage can be invaluable in supporting archaeological interpretations of sedimentary and burial environment, contextual integrity, truncation of features, cycles of erosion, as well as direct cultural impact on the assemblage itself.

5.2 Bone Fragmentation
High levels of fragmentation are often associated with the process of burning of bone. In this, the cultural processes of burning or cremation are essentially those of dehydration and oxidation in which the bone structure is degraded by the action of externally applied heat. This causes the appearance of fissures in the bone, typically leaving the bone prone to fragmentation along those fissures, and may be broken down into fragments as small as 25mm without any form of external disturbance (McKinley and Roberts, 1993); matrix compression, movement of the bone both during and after the burning process, and post-depositional effects will cause subsequent further fracturing, and reduction in fragment size.

Whilst much attention has been devoted to understanding heat-induced fracturing, controversy surrounds the interpretation of fractures in relation to the whether bone is burned whilst still fleshed, defleshed (green), or dry (degreased). It is now realised that there is no satisfactory method available, based on visual observation of bone, to differentiate the condition of the bone prior to thermal-alteration, with studies often contradictory and lacking any clear standardisation (Correia, 1997).

An assessment of levels of fragmentation within a cremation deposit is essential in assessing the bias imposed by fragmentation on the quality of the data retrieved from the analysis of burnt bone. In general the higher the level of fragmentation the less information the can be extracted from a deposit; fragmentation reduces potential identification to element and taxon, sex, age at death, and pathological assessment, and increases the likelihood of winnowing of bone from the deposit due to sub-aerial processes.

see pdf for the tables   pdf-    

Table 2 summarises the results of the quanitification of cremated bone in the Ardsallagh 2 assemblage presented by size fraction, weight, and percentage of total weight:

 

Table 2. Quantification of burnt bone fragmentation from Ardsallagh site 2, showing fragment count, bone sample weight (in grams), and percentage of total weight, divided by size fraction. The final column lists degree of fragmentation as a function of fragment density (total fragment count/total weight).

ARD2/009 (the smallest collected sample) was the most highly fragmented (46.5 fragments per gram) with the majority of the skeletal material <10mm in diameter; average fragment size was assessed at 2mm diameter. The largest recovered fragment was 16.4mm in diameter. The small sample weight and high degree of fragmentation rendered taxonomic identification impossible. The fragment edges were notably softened, with extensive rounding indicative of active sub-aerial weathering.

ARD2/105 showed a similar degree of fragmentation to ARD1/100 (12.6 fragments per gram) with the majority of the skeletal material <10mm in diameter, though with a significant portion of the sample in the 10 to 15mm, and >15mm ranges. The largest recovered fragment was 28.9mm in diameter. The fragment edges were notably softened, with extensive rounding indicative of active sub-aerial weathering.

5.2 Colouration
Burnt bone displays a wide variety of colours ranging from brown to grey-blue, black, grey, grey-white, and chalk white. Traditionally, colour change has been cited as evidence of firing temperatures (Correia, 1997) ranging from brown/orange (unburnt), to black (charred; c. 300°C), through hues of blue and grey (incompletely oxidised, up to c. 600°C) to the fully oxidised white (>c. 600°C). Colour is also seen as a reflection of organic and inorganic materials associated with the bone or body as it responds to increased temperatures; brown is associated with haemoglobin and/or soil discolouration, black with carbonization of bone in an oxygen-starved state, grey with organic pyrolization, and china white with the final stage of organic degradation and fusion of bone salts (ibid.).

Sample <10mm 10mm - 15mm

>15mm Total Degree of frag.

ARD2/009 Fragment count 182 3 1 186

Weight (g) 3.3 0.6 0.1 4.0

% of total weight 82.5% 15% 2.5% 100% 46.5

ARD2/105 Fragment count 1050 59 32 1141

Weight (g) 43.7 21.7 25.2 90.6

% of total weight 48.2% 24.0% 27.8% 100% 12.6

 

The results of the analysis of colour variation (table 3) in the fragments of bone indicate that both deposits contained bone that had been exposed to heat at a sufficient temperature (>600°C) in order to completely oxidise the bone with the loss of much of the organic component.

Both bone samples from Ardsallagh site 2 were almost uniformly white on both exosteal/endosteal surfaces, and in cross section. This would indicate the use of an efficient durational cremation process, with the organic matter exposed to higher temperatures for a considerable period of time or more efficient control of pyre heat loss.

Table 3. Range of colour variation in Ardsallagh 2 cremated assemblage.

 

6. Human Skeletal Remains

6.1 Inventory

See Appendix 1.

6.2 Age at Death Assesment
Assessing the age at death of an individual is one of the essential tasks in osteological analysis. Age studies have been used in a variety of situations including: (1) identification of the individual (in conjunction with sex determination) as part of forensic cases; (2) studying the adequacy of growth of children in a population which is seen as an index of overall community health - poor growth is an indicator of unfavourable developmental conditions, diet or environmental stress; (3) understanding age-related social status milestones in life – coming of age, marriage, etc; and (4) the construction of demographic profiles in an attempt to understand allochronic and/or diachronic patterning in mortality and funerary practices at the population level.

Academically, the assessment of skeletal age at death (SA) is an area of significant study and debate within osteology. SA should not be viewed as equivalent to chronological age at death. SA reflects the natural growth and development of the body in response to diet, environment and activity, rather than an absolute calendrical age; poor diet can produce delayed maturation and growth yielding a ‘younger skeletal age than real calendar years, and conversely, habitual activity can produce an aged, or ‘older’, skeleton than in reality. This realisation has profound bearing on many areas of archaeological inquiry with the effect that the criteria utilised in order to age an individual have to be carefully chosen and applied.

During the developmental phase of growth (intra uterine to around 21 years old) SA determination is based upon: (1) well-understood and predictable rates for the formation and eruption of the dentition, and growth and ossification of the skeleton which are used to age juveniles (Haaviko, 1970; Scheuer and Black, 2000 and 2004; Smith, 1991); (2) in sub-adults the unification or fusion of the bones of the postcranial skeleton provides a reliable marker within relatively tight statistical margins.

However, once growth has ended and adulthood is reached, age determination becomes more difficult as many of the criteria used are reflections of skeletal deterioration and ‘wear and tear’; as such they are highly variable in expression, and contextually mediated (Iscan and Loth, 1989; Molleson and Cox, 1993).

No surviving age-defining structures were encountered amongst the Ardsallagh site 2 human bone assemblage. This was due to the relatively high degree of fragmentation encountered, and the lack of surviving requisite areas such as complete epiphyseal ends of long bones. However, the overall size of the Ardsallagh human bone fragments, and the presence of closed apices in the recovered tooth root structures, suggests that all the identifiable remains were skeletally adult.

6.3 Sex Assesment
Determining the biological sex of an individual is both a central component of individuated analysis and fundamental to the construction of demographic profiles.

Like most primates, humans display a discrete pattern of morphological differentiation between males and females; this is termed sexual dimorphism (SD).

Some of these differences are associated with primary sexual characteristics of the reproductive system which includes pelvic morphology, whilst others present a host of inter-related morphological, physiological, and behavioural features that become manifest with the onset of the hormonal surge at puberty. These are referred to as secondary sexual features.

In general, a suite of established criteria are used for sexing adults on the basis of cranial and postcranial characters. These include differentiation in cranial characters (the expression of the nuchal crest, mastoid process, supra-orbital margin and ridge, and mental trigone), differentiation in pelvic morphology (greater sciatic notch, ventral arch, sub-pubic concavity, pre-auricular sulcus, and sacro-iliac articulation), and differentiation in overall size and robusticity including ratios of humeral/femoral head size, dental metrics, and joint surface area. The majority of these characteristics require evaluation of large or integrated skeletal structures, and the statistical efficacy of morphological sex-evaluation becomes less significant with increasing levels of bone fragmentation.

Due to the highly fragmented nature and lack of requisite surviving morphological structures, it was not possible to evaluate the sex of the Ardsallagh 2 skeletal remains.

 

6.4 Pathology
The study of palaeopathology investigates the evolution and expression of ancient disease processes through time and how human societies adapted to them. In studying diseases in archaeological populations we are primarily looking at those disease vectors that leave characteristic changes or lesions on the bony skeleton.

Palaeopathological assessment is generally undertaken for one of two reasons: firstly, to document the expression of skeletal disease process during the life of an individual, and secondly, to understand the demography of such pathologies at the population level and their change through time. The range of diseases commonly encountered and investigated includes: trauma, congenital abnormalities, circulatory disorders, joint diseases, infectious disease, diseases of the viscera, metabolic disease, endocrine disorders, hematological disorders, skeletal dysplasias, neoplastic disease, and various diseases and malformations of the dentition.

Some, such as traumatic lesions, are due to the application of external forces on bone.

Expression can range from the effects of crushes, trips or falls, to the impact of edged weapons and blunt force trauma. Others, such as the metabolic disorders, arise through the deficiency of essential nutrients and vitamins or the surplus of toxins;understanding their expression provides good evidence of dietary deficiency or environmental stress.

No pathological lesions were noted in the Ardsallagh 2 assemblage.

7. Summary

ARD2/009 ARD2/105

Type of deposit  - Urned burial Urned burial

Percentage survival -  c.5% c.5%

Total weight of crematedbone - 4.0g 90.6g

Weight of human bone 0g 16.4g

Maximum fragment size 16.4mm 28.9mm

Degree of fragmentation 46.5 f/g 12.6 f/g

Efficiency of cremation Overall colour: white

Efficient prolonged

>600°C

Overall colour: white

Efficient prolonged

>600°C

NISP 0 16

MNI 0 1

Age at death - Adult

Sex - Unobservable

Pathology - Unobservable

8. References

Correia, P.M.M. (1997). Fire modification of bone: a review of the literature. In W.D.

Haglund and M.H. Sorg (eds.) Forensic Taphonomy: The Postmortem Fate of Human

Remains. London: CRC Press. pp 275-293.

Haaviko, K. (1970). The formation of the alveolar and clinical eruption of the permanent

teeth. An orthopantographic study. Proceedings of the Finnish Dental Society 66: 101-170.

Iscan, M.Y. and Loth, S.R. (1989). Osteological manifestations of age in the adult. In M.Y.

Iscan and K.A.R. Kennedy (eds.) Reconstruction of Life from the Skeleton. New York: Alan

R. Liss, Inc. pp 23-40.

McKinley, J.I. and Roberts, C.A. (1993). Excavation and post-excavation treatment of

cremated and inhumed human remains. Institute of Field Archaeologists Technical Paper 13:

1-11.

Molleson, T. and Cox, M. (1993). The Spitalfields Project Volume 2: The Anthropology.

Council for British Archaeology: CBA Research Report 86.

Scheuer, L. and Black, S. (2000). Developmental Juvenile Osteology. San Diego: Elsevier

Academic Press.

Scheuer, L. and Black, S. (2004). The Juvenile Skeleton. London: Elsevier Academic Press.

Smith, B.H. (1991). Standards of human tooth formation and dental age assessment. In M.A.

Kelley and C.S. Larsen (eds.) Advances in Dental Anthropology. New York: Wiley-Liss. pp

143-168.

 

9. Appendix 1: Catalogue of Identifiable Specimens

Site Anatomical

elements Description NISP Taxon

ARD2/009 - NO IDENTIFIABLE ELEMENTS - -

ARD2/105 Humerus Left distal diaphyseal fragment 1 Homo

Cranial vault Small squame fragments 4 Homo

Humerus Unsided diaphyseal fragments 3 Homo

Tooth Root apices of mandibular premolars 2 Homo

Fibula Unsided diaphyseal fragments 4 Homo

Rib Shaft fragment 1 Homo

Metatarsal Unsided diaphyseal fragment 1 Homo