Bone diagenesis in the European Holocene II: taphonomic and environmental considerations

We have applied cluster analysis to mercury intrusion porosimetry data from 219 archaeological bones (121 human and 98 animal) and soil chemistry data from 219 accompanying soil samples (1 per bone sample), to investigate the influence of soil chemistry on bone preservation. The samples chosen for the study were obtained from sites ranging in time from the pre-modern to the Mesolithic and were representative of burial environments across Europe (from the Baltic to the Mediterranean). These results represent the single largest database for archaeological bone preservation in the European Holocene to date and demonstrate the potential for large-scale diagenetic studies to help develop long term preservation strategies for our European heritage. Despite the variety of sites and environments, bones could be categorised into only four main diagenetic types. Furthermore, soil chemistry appears to significantly affect only one type of preservation, the pathway characterised by loss of mineral. In neutral to basic soils, taphonomy and in particular the differences between the treatment of human and animal remains, becomes the dominating factor in determining preservation. Using these results, strategies for heritage management of archaeological sites can be suggested; grouping sites into those requiring immediate excavation and those where in situ preservation is viable.     

Diagenesis and survival of osteocalcin in archaeological bone

It has been demonstrated that the protein osteocalcin can survive in bone in the archaeological record, and postulated that it has the potential to survive over geological time periods. The precise mechanism for this longevity of survival is not yet fully understood, and has not been extensively studied in comparison to other diagenetic aspects of archaeological bone. We report a comparison between osteocalcin survival and the state of preservation of more than 60 bones from 14 archaeological sites. The amount of osteocalcin, assayed immunologically, was compared with diagenetic parameters that measure: the amount of ‘collagen’ in the bone, the mineral changes, the porosity, and the histological preservation of the material. The findings indicate that microbial taphonomy and mineral alteration of bone have a profoundly damaging effect on the preservation of osteocalcin.     

Experimental effects of bone size and temperature on bone diagenesis

In the ground, bone undergoes chemical and physical changes which affect its preservation. This fact has important implications for dating and other analytical procedures involving bone, as well as faunal analysis where differential preservation of bones of different species may affect conclusions regarding the relative significance of an animal to the economy of a given society. The diagenic processes in bone range from minor changes in the bone protein to complete structural and chemical breakdown.Using fresh cow bone, we conducted laboratory experiments which simulate the effect of temperature and bone size on the rate and nature of bone disintegration in archaeological sites. Temperature influences the rate of chemical change, and bone size and density affect the accessibility of the molecular constituents of bone to extrinsic chemical reactions. These findings clarify the importance of two well-known concepts in bone taphonomy. (1) The rate of chemical breakdown in bone tissues is related to the proximity of a given unit of tissue to the bone surface. This means that, in archaeological bone samples, tissue near the surface may be different chemically from tissue away from the surface and great care is necessary in choosing and preparing bone samples for analytical procedures. (2) In general, small bones are not as well preserved as large bones, therefore small animals are likely to be underrepresented in faunal assemblages.     

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones.     

Taphonomy and experimentation

Many experiments have been conducted in the field of taphonomy in order to understand the effects of some agents and the associated pattern and process of bone modifications. A review of these experiments and the patterns of bone modifications is presented here. Numerous experiments focus on peculiar points of bone accumulation, mainly to gain knowledge about human habits and practices, but the action of some taphonomic agents has also been explored, among them, diagenetic processes. The striking feature of all these works are that they are localized, performed on non–statistical samples and without repeatability. Very few experiments combine different agents to fit more closely to the complexity of most fossil bone accumulations.     

Túnel: A Case Study of Avian Zooarchaeology and Taphonomy

Although not often considered, there are many osteological characters unique to the avian skeleton that influence the taphonomy of bird bones. These characters are reviewed and their archaeological significance discussed herein. The presence of marrow in many avian long bones is important to interpretation of avian remains from archaeological sites because the presence of marrow affects bone density and, in turn, preservation. Other structural properties that affect avian bone preservation include cortical wall thickness, length and pneumatic state. Based on an analysis of approximately 10,000 bird bones from the archaeological site of Túnel, Tierra del Fuego, Argentina, I found that specific breakage patterns resulted from natural taphonomic processes acting as a result of the unique avian bone characteristics. This information may allow researchers to distinguish breakage patterns in avian bones resulting from natural taphonomic processes from breakage patterns that are culturally induced.     

Pick the Right Pocket. Sub‐sampling of Bone Sections to Investigate Diagenesis and DNA Preservation

Many archaeological bones display a heterogeneous degradation pattern. Highly degraded bones could contain pockets of well‐preserved bone, harbouring good quality DNA. This dichotomy may explain why the relationships between global bone preservation parameters such as histological integrity, bone mineral crystallinity or collagen yield, and bulk DNA preservation/amplification success rate have been found to be at best, weak to moderate. In this pilot study, we explore whether or not a more localised approach will highlight a stronger relationship between diagenetic parameters and DNA preservation. This study includes a detailed histological characterisation of bone diagenesis in sub‐areas of three bone samples. Regions of the same bone, which displayed differential degrees of preservation or type of diagenesis were sampled for further analysis and both genetic (small scale Illumina MiSeq sequencing) and chemical (Fourier‐transform infrared spectrometric analysis) analyses were performed. The aim was to investigate how bone diagenetic processes relate to DNA preservation at a higher resolution than in previous studies. This is key in order to improve DNA analytical success rates. The expected relationship between bone and DNA preservation (retrieved endogenous DNA) was observed and the results corroborate previous work that DNA preservation is linked to the integrity of bone collagen and mineral. The results further suggest that non‐biological diagenetic alterations such as etching and the presence of mineral infiltrations and inclusions have a negative effect on DNA preservation/extraction. Copyright © 2016 John Wiley & Sons, Ltd.     

Assessing the contribution of integrated geoarchaeological approaches to understand the formation and function of burnt mounds: the example of Hoppenwood Bank,North Northumberland

Burnt mounds are detrital mounds of fire-cracked rock and charcoal, deposited as the result of a prehistoric process for heating water. They are the most numerous prehistoric monument found across Britain and Ireland and have traditionally been difficult to study due to their apparent homogeneity and lack of distinguishing features. This study seeks to change the discussion surrounding burnt mounds and evaluates a large early- to mid-Bronze Age burnt mound at Hoppenwood Bank in Northumberland using an integrated microarchaeological methodology, the contribution of which is assessed. A combination of micromorphology and silicic microfossil analyses indicates that these deposits are complex and multifaceted, showing variability in their depositional sequences, microcomponents, and taphonomy. The identification of hiatuses in deposition and desiccation of surfaces beneath the burnt mound indicate that the accumulation of material may have been periodic or seasonal, and dating suggests that sequential deposition may have spanned 500–700 years. Taphonomic issues identified at the microscale highlight concerns for the interpretation of microfossils. This paper considers the implications of these observations and argues that burnt mounds should be viewed as caches of environmental and sediment-based data, indicative of sequences within landscape use-patterns and human-environment interactions.     

Are Teeth Better? Histological Characterization of Diagenesis in Archaeological Bone–Tooth Pairs and a Discussion of the Consequences for Archaeometric Sample Selection and Analyses

Teeth are often the preferred source material for isotopic and genetic assay involving ancient biomolecules. The assumption is that dental tissue preserves better due to its anatomically protected location, the enamel cap, and lower porosity compared to bone. However, this assumption has not been widely tested. Some similarities in diagenetic processes are to be expected due to similarities in structure and chemical composition of dentine and bone. This has led to the suggestion that bone can be used as an indicator of dental preservation, as a pre‐screening technique in the selection of suitable samples for biomolecular studies. Thus, direct testing of the correlation between bone and tooth preservation and diagenesis is needed. This paper reports the results of the histological characterization of diagenetic alterations within 25 human femur–tooth pairs, from a Medieval to modern (AD 1850) cemetery in Eindhoven, the Netherlands. The results showed that teeth do indeed preserve better overall, but not always, and that this was dependent on the main diagenetic factor(s) at the burial location. Furthermore, good correlations are found between the microstructural preservation of bone and teeth; similar processes of decay were observed within bone and teeth of the same individual. Overall, the study demonstrated that histological analysis of bone is useful for the identification of degradation processes that affect biomolecular preservation in skeletal material. In this way, sample selection and analytical strategies can be optimized. Copyright © 2013 John Wiley & Sons, Ltd.     

Biochemical and physical correlates of DNA contamination in archaeological human bones and teeth excavated at Matera,Italy

The majority of ancient DNA studies on human specimens have utilised teeth and bone as a source of genetic material. In this study the levels of endogenous contamination (i.e. present within the sample prior to sampling for the DNA analysis) are assessed within human bone and teeth specimens sampled from the cemetery of Santa Lucia alle Malve, Matera, Italy. This site is of exceptional interest, because the samples have been assayed for 18 measures of biochemical and physical preservation, and it is the only one identified in a study of more than 107 animal and 154 human bones from 43 sites across Europe, where a significant number of human bones was well preserved. The findings demonstrate several important issues: (a) although teeth are more resilient to contamination than bone, both are readily contaminated (presumably through handling or washing), and (b) once contaminated in this way, both are difficult (if not impossible) to decontaminate. Furthermore, although assessed on bone samples, several of the specific biochemical and physical characteristics that describe overall sample preservation, levels of microbial attack and related increases in sample porosity directly correlate with the presence of observable contamination in both bone and teeth samples from individual samples. While we can only speculate on the cause of this relationship, we posit that they provide useful guides for the assessment of whether samples are likely to be contaminated or not.     

Neandertal Behavior at the Middle Palaeolithic Site of Abric Romaní, Capellades,Spain

Abstract

This paper synthesizes the work carried out since 1983 at the Middle Palaeolithic site of Abric Romaní, Spain, reconstructing Neandertal behavioral and settlement patterns. The sedimentary features of this site give a high resolution of prehistoric occupational events. Large surface excavation (over 300 sq m) has been used to obtain a detailed picture of intrasite settlement patterns. The reconstruction of activities and their spatial and temporal organization is a key issue in the debate concerning the cultural capabilities of Neandertals versus anatomically modern human beings, and our interpretation integrates geoarchaeology, lithic technology, taphonomy, zooarchaeology, and anthropology. In this way, we explain the degree of diversity within a single Neandertal archaeological site, especially regarding lithic assemblage variability, faunal processing activities, and settlement patterns.     

A taphonomic study of the African wild dog (Lycaon pictus)

Carnivore taphonomy has been traditionally used for the interpretation of archaeological sites in order to discriminate human-generated or modified from non-anthropic bone assemblages. In most of this actualistic research, the focus has mainly been placed on hyenas and felids, neglecting other carnivores. This paper analyzes the taphonomic impact of the African wild dog (Lycaon pictus) on equid bones and compares it with the bone modification patterns produced by other canids, such as wolves (Canis lupus) in order to compare medium-/large-sized canid variability on bone modification patterns and elaborate a referential framework which could be feasibly applied to the zooarchaeological record to detect canid intervention on archaeological assemblages in the past.     

Focused,intense and long-term: evidence for granular ark (Anadara granosa) exploitation from late Holocene shell mounds of Blue Mud Bay,northern Australia

Explanatory frameworks relating to the appearance of shell mounds and the exploitation of molluscs (particularly the sand/mudflat bivalve Anadara granosa) during the late Holocene have tended to emphasise stasis and continuity. Very few analyses have adequately investigated the intensity of human predation during the mound period and the potential effects on the particular prey species. To this end, the biological and ecological characteristics of A. granosa, the dominant molluscan species for much of the known period of occupation in the region, are considered in detail, in combination with assessing the potential for human impact through predation via the measurement of 9106 A. granosa valves from three shell mounds. In explaining long-term economic change in this region of northern Australia, the focus has been placed on the analysis of relative changes and trends through time in prehistoric resource exploitation.     

Assessing the distribution of African Palaeolithic sites: a predictive model of collagen degradation

In order to assess the distribution of African Palaeolithic sites and hominin remains, we need an understanding of the factors that may affect the preservation of archaeological material in the fossil record. One of the main factors that is thought to affect seriously the global distribution of fossil remains is taphonomy, but it would seem that taphonomic processes may themselves be overprinted by collagen degradation.The rate of collagen loss is highly temperature dependent, and it has been shown that bone is more likely to be preserved in areas of lower temperature and so lower collagen loss. Hence, it would be expected that fossil fauna remains would be distributed in areas of low collagen loss, i.e. low temperature. Conversely, lithics will not be subject to a temperature bias in their preservation. We have tested this hypothesis through the use of archaeological material.Our results show that the distributions of both lithic and faunal assemblages are non-random across the African continent, with all archaeological sites being found in areas of relatively low collagen degradation. This implies that bone collagen degradation is not the only factor affecting the distribution of African Palaeolithic sites and hominin remains. We suggest that the site distribution is not a reflection of bias in excavation history, but is a real phenomenon reflecting hominin habitat choice.     

The Art of Taphonomy and the Taphonomy of Art: Layer IV,Molodova I,Ukraine

Level IV of Molodova I, an open-air Middle Paleolithic site in the Ukraine has been described by some researchers as a possible source of evidence for early symbolic behavior. We examined bone objects from this layer that were identified by Ukrainian researchers as exhibiting possible Neandertal produced engravings including two anthropomorphic figures. While we have determined that there is no evidence of symbolic activity at Molodova I, the database we have created, with its systematic recording of traces left by taphonomic agents on faunal remains, provides a better understanding of the overall site taphonomy.     

The Bronze Age landscape of the Bjäre peninsula,southern Sweden,and its relationship to burial mounds

Palaeoecological analyses from a small fen deposit, combined with pollen analysis from buried soil profiles under prehistoric burial mounds, have been used to investigate the timing and vegetation change associated with the Holocene development of a cultural landscape in southern Sweden. Traditional pollen analysis is complemented with plant macrofossil analysis and soil pollen analysis from within and in close proximity to the burial mounds in the coastal Bjäre peninsula, well known for its high density of well-preserved Bronze Age monuments. The vegetation development is linked to the construction of the burial mounds. A marked increase of cultural impact on the landscape is recorded during the Neolithic–Bronze Age transition and estimates of landscape openness suggest that by the onset of the Bronze Age, forest cover was only 20–40%, falling to 10% in the immediate vicinity of the burial mounds themselves. The coastal strip appears to have been affected by human activity to a greater extent and at an earlier date than sites from further inland in southern Sweden and the Bronze Age burial mounds were most likely designed to be visible in a largely deforested landscape.     

Taphonomic modifications produced by modern brown bears (Ursus arctos)

Actualism has been a fundamental tool in taphonomy. The knowledge of accumulation patterning of modern faunal allows us to interpret the activity of different actors in the archaeological record and to reconstruct the behaviour of preterit animals and humans in which we are interested. However, until now, there are few works that include bone modifications made by bears amongst those made by carnivores. Most data about bone modifications made by bears have been obtained from the archaeo‐palaeontological record. In most of these assemblages, the presence of bears is related to their period of hibernation. Therefore, in these contexts, the changes documented on recovered bear bones are associated only with cannibalism. In this paper, we present an actualistic study about modifications on bones made by modern brown bears. These animals can cause damage similar to those produced by other large carnivores. Generally, bear activity leaves slight damage, mainly on large‐sized animal bones. However, on bones of small‐sized animals and those of greater fragility, the bears can produce abundant damage. Though not usual, bears can break long bones and consume the complete epiphysis. This study suggests that bears have the potential to be agents of bone modification in fossil assemblages. Consequently, they should be considered as a possible agent of modification of faunal remains in the fossil record. Copyright © 2011 John Wiley & Sons, Ltd.     

Familienanalyse in kupferzeitlichen Kollektivgräbern aus Umm an-Nar; Abu Dhabi

Skeletal material from three collective burials from the island of Umm an-Nar (Arabian peninsula) dating to the 3rd millennium B.C. was submitted to a kinship analysis with the aid of a set of genetically determined odontologic traits. The analysis yielded the following results: a) phenotype and frequency of odontological traits in the skeletal sample suggest a relatively homogeneous population; and b) there are distinct indications for genetically determined relationships within the individual burial mounds. In spite of the poor state of preservation of the skeletons, the analysis permitted conclusions about the social structure of the local population.     

In situ Preservation Solutions for Deposited Iron Age Human Bones in Alken Enge,Denmark

The rich mass deposition of Iron Age human bone material from the Danish site, Alken Enge, is extraordinary not only from an archaeological perspective but also from a preservation point of view. The main find is situated in a waterlogged, anoxic environment which provides excellent preservation conditions and therefore enables in situ preservation of the human bones. However, major differences in local environmental conditions challenge an in situ preservation of the entire site area as parts of the bone material presently deteriorate. In this paper, a multi-proxy environmental monitoring approach is used to document threats and to suggest the best preservation solution for the archaeological finds, whether in or ex situ.     

Human taphonomy at Khuzhir-Nuge XIV,Siberia: a new method for documenting skeletal condition

This paper employs a new three-part method for documenting skeletal condition in order to examine human taphonomy at the Glaskovo (5000–3700 BP, calibrated) cemetery of Khuzhir-Nuge XIV, located in the Lake Baikal region of Siberia (Russia). Relationships among three distinct aspects of condition – completeness, fragmentation, and articulation – and 15 identified taphonomic factors are investigated in order to explain the high variability observed at the site. Intrinsic skeletal characteristics such as element type and age at death were found to be responsible for some of the variable condition, but cultural activities, particularly mortuary practices, appear to have played even greater roles – both direct and indirect. Articulation, in particular, appears to have been an aspect of skeletal condition which was directly affected by a number of cultural practices. In addition to applying a new method of documenting skeletal condition to human taphonomic analyses, this research explains much of the variable condition observed at Khuzhir-Nuge XIV and emphasizes the significance of cultural practices as taphonomic agents affecting human remains.