FLUORINE IN FOSSILIZED BONE AND TOOTH: DISTRIBUTION AMONG SKELETAL TISSUES

Because of differences in their physical properties, bone, tooth dentine and tooth enamel react very differently during the course of fossilization. This relationship is shown clearly in the case of diagenetic introduction of fluorine wherein bone and dentine with high permeability and small apatite crystallite size contain 2–3 times the amount of fluorine as coexisting enamel with its low permeability and large crystallites. Smaller differences in the same sense are found within bone types from the same species, and care must be used in applying fluorine content methods even among bones from the same deposit.     

Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Bone reactivity offers a potential way to record local physical–chemical conditions prevailing in fossilization environments and archaeological sites. In the present study, a series of fossil bone samples from the karstic environments of the Bolt's Farm cave system (Cradle of Humankind, South Africa) and from fluvio‐lacustrine environments of the Tugen Hills (Gregory Rift, Kenya) is analysed. The chemical composition and infrared and nuclear magnetic resonance (NMR) spectroscopic properties of fossil samples point to a transformation of the biogenic apatite and formation of secondary apatite. Depending on the sample, the secondary apatite corresponds to a carbonate‐bearing hydroxy‐ or fluor‐apatite. The maximum fraction of secondary apatite is close to 60%, coinciding with previous observations in experimental alteration of bone in aqueous solutions and suggesting that a fraction of pristine biological apatite is likely to be preserved. The present results also suggest that the acetic acid treatment of fossil samples moderately increases their average crystallinity but may dissolve carbonate‐rich domains of secondary apatite.     

Daily rates of dentine formation in macaque tooth roots

When tetracycline antibiotics are administered either orally or by injection they bind at the forming mineral front of the dentine and become incorporated into teeth as a permanent label. In this study, oxytetracycline was used as a label in order to investigate the growth of root dentine in macaques. There are no good data available in the literature for daily rates of root dentine formation over a prolonged period of time in either humans or macaques. Records of ten doses of oxytetracycline administered orally at irregular intervals (but at the same time of day) over a period of 10 months to a young rhesus macaque monkey (Macaca mulatta) were used to calculate the rate of dentine formation in tooth roots. Rates of dentine formation in the first portion of third permanent molar root formation, and in the apical portion of permanent canine and premolar root formation, were consistently between 3 μm and 4 μm per day. There was no evidence in this study of a gradual decrease in daily dentine formation rate from the crown to the root, or along the length of a dentine tubule through the bulk of the dentine, as has been implied previously. With the exception of faster rates recorded in cusps or slower rates recorded at the very beginning or very end of primary dentine secretion in other studies, the results of the present study suggest a consistent rate of dentine formation in permanent macaque teeth. What data there are for human dentine formation rates suggests that it is likely this finding can be extended to human dentine as well.     

CHILDHOOD DIET: A CLOSER EXAMINATION OF THE EVIDENCE FROM DENTAL TISSUES USING STABLE ISOTOPE ANALYSIS OF INCREMENTAL HUMAN DENTINE*

Incremental dentine analysis utilizes tissue that does not remodel and that permits comparison, at the same age, of those who survived infancy with those who did not at high temporal resolution. Here, we present a pilot study of teeth from a 19th‐century cemetery in London, comparing the merits of two methods of obtaining dentine increments for subsequent isotope determination. Covariation in δ¹³C and δ¹⁵N values suggests that even small variations have a physiological basis. We show that high‐resolution intra‐dentine isotope profiles can pinpoint short‐duration events such as dietary change or nutritional deprivation in the juvenile years of life.     

THE ENVIRONMENTAL STABILITY OF ANCIENT CERAMICS

A series of corrosion experiments was carried out using identical samples of a ceramic of known composition, structure and density which were subjected to a variety of simulated soil solutions. The action of the solutions was monitored by measuring their pH as a function of time at 25 °C and 90 °C. Under all conditions the pH stabilized rapidly. Microscopic and electron microscopic studies showed the presence of reaction/alteration products that would account for the observed pH changes. The findings indicate that ancient ceramics that exhibit no physical deterioration will have below their surface a composition corresponding to the composition of the sherd at the time of its burial.     

Formation of the Florisbad spring and fossil site – an alternative hypothesis

In considering that fossilization could not have taken place in the areas of the spring vents at Florisbad, and that the spring-water was not responsible for fossilization, this hypothesis provides an alternative environment for the fossilization of faunal remains. Based on examination of the site, studies on various aspects of the site, as well as previous hypotheses on the formation of the site, an alternative theory on the formation of the Florisbad spring site is presented. It is contended that a large spring pan developed around the springs, which was later largely covered, and transformed into a dam, by the migration of the Florisbad sand dune. When the water rose to near the top of the Florisbad dune dam, the eastern arm of the dune was breached, evacuating the contents of the dam in a flood of water and sediments. This caused the ephemeral drainage line to the east, to be modified into a flat-bottomed marshy vlei, where the majority of the dam sediments were deposited. Previously largely unanswered and debatable questions such as the erosion of the eastern side of the spring site, the 7 m of clay deposits recorded in the modified vlei area, and aspects of the Peat IV layer are addressed. The importance and influence of the panveld and sand dunes in the formation of the spring site are also examined.     

New parameters for the characterization of diagenetic alterations and heat-induced changes of fossil bone mineral using Fourier transform infrared spectrometry

Diagenetic alteration may limit the potential use of the biogenic composition of fossil bone as a reliable source of information for dietary, environmental and climatic reconstructions. One of the key parameters used to determine the state of preservation of fossil remains is their crystallinity. This can be evaluated by means of infrared spectroscopy, measuring the “splitting factor” (IRSF). However, the crystallinity may fail to describe the extent of chemical and mineralogical changes occurring during fossilization, and cannot be used alone as a reliable indicator of biogenic signal preservation.     

常用清洗材料对瓷器的影响研究

为了探讨常用化学清洗材料对瓷器的影响,通过清洗前后形貌对比实验和胎、釉溶出物实验,对常用清洗材料的清洗效果和对瓷器的损伤作了对比研究。结果表明,盐酸、草酸、柠檬酸、六偏磷酸钠、EDTA二钠盐对附着紧密的黄色沉积物有很显著的清洗效果;各种清洗材料对瓷器或多或少均有一定的损伤,碱性溶液、络合材料对瓷器的腐蚀都比较强,酸性材料中的硝酸、草酸、盐酸也会产生较强的腐蚀作用;一般情况下清洗能力较好的清洗液,对瓷器的损伤也很强。     

Dental root dentine translucency used in age determination of medieval Norwegians from Trondheim

A pilot study on eight skulls from the churchyard of St Olav's church in Trondheim, excavated in 1988–1989, was carried out to compare age determined by root dentine translucency with the age assessed by a physical anthropologist. The difference in mean age between the two methods was not significant (p = 0.06). Age determinations based on root dentine translucency were then performed on removable teeth from the adults among the 248 skeletons found in the same churchyard, excavated in 1984–1985. A comparison between the ages determined using root dentine translucency and the ages previously determined by the direct inspection method was performed. A significant systematic difference was seen between the two methods (p = 0.000). The root dentine translucency method gave an age range for the cohort excavated in 1984–1985 between 30 and 72 years, whereas the direct inspection method gave a range between 15 and 63 years. Because evaluation of many criteria are required to achieve reasonably accurate estimates of age in connection with the direct inspection method, expertise in skeletal biology is necessary. The method of measuring root dentine translucency as a tool in archaeological and anthropological work and fieldwork and in forensic science seems to have advantages because the method can be used without previous extensive training.     

Rates of dentine mineralization in permanent human teeth

Previous experimental studies have estimated linear rates of dentine formation in modern humans to be close to 4μm day⁻¹. In this study a method similar to that first adopted by Kawasaki, Tanaka and Ishikawa⁵ was used to estimate linear rates of dentine mineralization over a period of 1200 days in both the cusps and cervical regions of several permanent tooth types. All teeth were from the same individual. Rates in the cusps of teeth with the tallest crowns were estimated to be between 5 μm day⁻¹ and 6 μm day⁻¹. This is higher than previous estimates in permanent tooth crowns, although rates in the cusp of a first permanent molar, where cusps were less tall and cuspal dentine therefore less thick, were close to previous estimates of 4 μm day⁻¹. Despite this variation in cuspal rates, mineralization rates were linear in all cusps studied over a long period of time. Rates in the cervical region, either close to the enamel dentine junction or to the cement dentine junction, were estimated to be between 1.3 μm day⁻¹ and 1.5 μm day¹¹, much slower than reported previously. Rates in the mid-portion of the dentine, in both the lateral part of the crown and in the cervical one-third of the root, rose steadily to match rates in the cuspal region, but then slowed towards the pulp chamber. These data extend the findings of previous studies on permanent human dentine. They demonstrate a wide range of mineralization rates in permanent dentine and provide a more secure basis for judging different rates in different locations of different human tooth types.     

DETERIORATION ASSESSMENT OF WATERLOGGED ARCHAEOLOGICAL LIGNOCELLULOSIC MATERIAL VIA 13C CP/MAS NMR*

This study investigates the residual chemical composition of waterlogged archaeological lignocellulosic material found in Greece. Hazelnut pericarps and oak wood found in a 16th‐century wreck, along with endocarps of olives dated at 300 bc , were examined. ¹³C CP/MAS NMR was applied to compare fresh and waterlogged archaeological materials. Results show qualitative alterations in their composition. The virtual absence of peaks at ~21 ppm and ~173 ppm, corresponding to hemicelluloses in all archaeological materials, indicates that these constituents can be an important indicator in assessing the type and degree of deterioration.     

Bear dentine aspartic acid racemization analysis: a proxy for the dating of Pleistocene cave infills

A high correlation between chronometric determinations based on aspartic acid racemization ratios and radioactive dating methods is described from samples of cave bear (Ursus deningeri and Ursus spelaeus) dentine. For samples from a very restrictive environment, as deep cave bear sites are (in view of their highly stable geochemical and thermal history), an age calculation algorithm was obtained. It has been found that there is a very close relationship between collagen preservation, from total aspartic acid in the > 3500 D fraction, and the amino acid racemization.     

AMBER FROM THE DOMINICAN REPUBLIC: ANALYSIS BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

The carbon-13 NMR spectra of amber from several mining sites in the Dominican Republic show considerable variation. In certain cases the differences are sufficiently distinct to serve as a reliable indicator of provenance. The gradations within the resonances of unsaturated carbons may reflect the relative ages of the samples, because fossilization and diagenesis can remove this functionality.     

A longitudinal study of tooth growth in a single individual based on long- and short-period incremental markings in dentine and enamel

Ground sections of teeth from a single individual revealed approximately 30 fluorescent lines in the dentine resulting from successive courses of tetracycline antibiotics given over a period of approximately 12 years. In addition, many teeth showed long-period incremental markings in the dentine. Short-period daily cross-striations in the enamel were used to calculate the periodicity of the long-period incremental lines in both enamel and dentine. The incremental markings in the dentine were then used to calibrate the time of administration of each of the courses of tetracycline antibiotics. Enlarged micrographs of the teeth, constructed using fluorescence microscopy, were used to measure the increase in height of different teeth throughout the growth period on each occasion the tetracycline antibiotics were given. The times of initial mineralization of the teeth and the duration of crown formation were also determined for each tooth section. Line plots of tooth height against age were computed and used to calculate the rate of increase in tooth height during crown and root formation for one example of each tooth type. Initial rates of increase in height during enamel apposition and coronal dentine formation were fast, between 10 μm and 14 μm per day. During the latter phase of crown formation and during early root formation, tooth height increased at a slower rate of between 4 μm and 6 μm per day. Rates of increase in tooth height then rose to between 13 μm and 26 μm per day during the second half of root formation before falling off to a rate of approximately 4 μm per day during root completion (as the root apex formed). The times of initial crown mineralization and the total crown formation times estimated in this individual were all within the range known for modern humans but there was comparatively early mineralization of the third permanent molar. These findings are discussed in the context of other studies on human dental development.     

Detection of Dietary Changes by Intra-tooth Carbon and Nitrogen Isotopic Analysis: An Experimental Study of Dentine Collagen of Cattle (Bos taurus)

Hypsodont teeth potentially contain a record of dietary or environmental changes occurring during their growth. The aim of our study is to understand how a dietary change is recorded in dentine collagen. Analyses were conducted on five steers (Bos taurus) raised in an experimental farm. From birth until weaning the steers were fed on a C₃diet; after weaning they were fattened on a C₄/C₃mixed diet until slaughter. Dentine collagen was sampled on demineralized molars from top to bottom. The change from the C₃to the C₄/C₃diet and weaning are both reflected in intra-tooth variations in δ¹³C and δ¹⁵N values, respectively. The abrupt change in carbon isotopic composition of the diet is reflected by a progressive change of the dentine collagen δ¹³C values. The gradual change may reflect sampling strategy and/or gradual turnover of the metabolic nutrient pool. The weaning process is reflected by a decrease in δ¹⁵N that exactly coincides with increase in δ¹³C. This demonstrates that when steers are weaned to a protein-poor diet, δ¹⁵N traces the cessation of suckling. Archaeological applications of this study are considered, including determination of the duration of lactation in prehistoric herds, and detection of residential mobility in cattle herders.     

Developmental defects and postmortem changes in archaeological pig teeth from Fais Island,Micronesia

The study investigated developmental defects of the dental hard tissues and postmortem changes in archaeological pig molars from Fais Island, Micronesia. The developmental defects of enamel were indicative of a disturbance of the secretory stage (accentuation of the incremental pattern, occurrence of Wilson bands and of hypoplastic defects) and the maturation stage of amelogenesis (hypomineralisation). Presence of coronal cementum in an M₃ indicated a partial premature breakdown of the reduced enamel epithelium or a partial demise of the enamel organ earlier during tooth development. Developmental defects of dentine presented as accentuated Andresen lines and areas of interglobular dentine. The pattern of developmental defects in the studied molars and the fact that deciduous premolars of the pigs from Fais did not exhibit developmental defects on macroscopic inspection are consistent with the hypothesis that the tooth defects were caused by periods of severe nutritional stress occurring after weaning. Postmortem changes caused by microbial infiltration were recorded in dentine and cementum. A presumed case of soft tissue preservation in the form of presence of odontoblast processes was observed in an M¹.     

CHEMICAL COMPOSITION OF A BOG BODY ADIPOCERE

Chemical analyses were carried out on adipocere obtained from a bog body recovered from a peat bog at Meenybradden, County Donegal, Ireland. Chromatographic (thin-layer chromatography and gas chromatography) and mass spectrometric analyses, combined with microanalytical chemical transformations, have yielded detailed compositional information. An absence of intact triacylglycerols, diacylglycerols and monoacylglycerols indicates that hydrolysis is complete. Consequently the adipocere is composed mainly of fatty carboxylic acids. The high proportion of palmitic and stearic acids, together with depleted oleic acid content, indicates that extensive reduction and, possibly, β-oxidation have occurred during burial in the peat bog. Hydration of the double-bond in oleic acid has also occurred, as is shown by the formation of 10-hydroxystearic acid. The monoenoic fatty carboxylic acids that are present, composed mainly of C₁₈ and C₁₆ compounds, comprise a mixture of positional isomers. The results are compared and contrasted with those obtained from previous studies of the lipid composition of other adipoceres and cadavers of archaeological interest.     

A new method of dentine microsampling of deciduous teeth for stable isotope ratio analysis

Carbon and nitrogen stable isotope ratio analysis of dentine is a powerful tool for examining early childhood diet in past populations. Serial sampling of the dentine can reconstruct an individual's changing diet. Previous serial studies have used homogenized samples that give broad results for age categories. This study presents a new dentine microsampling technique for use in stable isotope ratio analysis that provides stable isotope signals for three important juvenile life stages: fetal life, breastfeeding, and weaning.     

AN EVALUATION OF ANALYTICAL AND INTERPRETATIVE METHODOLOGIES FOR THE EXTRACTION AND IDENTIFICATION OF LIPIDS ASSOCIATED WITH POTTERY SHERDS FROM THE SITE OF SAGALASSOS,TURKEY*

Three lipid analysis methods were applied to extracts of archaeological potsherds from the ancient city of Sagalassos, south‐west Turkey. In the fatty acid methyl ester fraction, obtained by selective transesterification of acylglycerols, the ratio of methyl palmitate to methyl stearate was determined. Secondly, by means of gas chromatography– combustion–isotope ratio mass spectrometry (GC–C–IRMS), stable carbon isotope ratios were measured for the same methyl esters. Finally, triglyceride composition was determined via high‐performance liquid chromatography–mass spectrometry (HPLC–MS). All three methods can be used to trace the origin of animal fat. Agreement between them is reasonable, especially in recognizing ruminant adipose fat. One sample was found to be of dairy origin using both GC–C–IRMS and HPLC–MS. The advantages of the various methods are discussed. Variations in lipid composition were observed between samples from different periods and excavated in diverse areas within the city of Sagalassos.