The decomposition of starch grains in soils: implications for archaeological residue analyses

Recent research involving starch grains recovered from archaeological contexts has highlighted the need for a review of the mechanisms and consequences of starch degradation specifically relevant to archaeology. This paper presents a review of the plant physiological and soil biochemical literature pertinent to the archaeological investigation of starch grains found as residues on artefacts and in archaeological sediments. Preservative and destructive factors affecting starch survival, including enzymes, clays, metals and soil properties, as well as differential degradation of starches of varying sizes and amylose content, were considered. The synthesis and character of chloroplast-formed ‘transitory’ starch grains, and the differentiation of these from ‘storage’ starches formed in tubers and seeds were also addressed. Findings of the review include the higher susceptibility of small starch grains to biotic degradation, and that protective mechanisms are provided to starch by both soil aggregates and artefact surfaces. These findings suggest that current reasoning which equates higher numbers of starch grains on an artefact than in associated sediments with the use of the artefact for processing starchy plants needs to be reconsidered. It is argued that an increased understanding of starch decomposition processes is necessary to accurately reconstruct both archaeological activities involving starchy plants and environmental change investigated through starch analysis.     

Alkaline cooking and stable isotope tissue-diet spacing in swine: archaeological implications

In this study we examine the effects of alkaline cooking on carbon and oxygen stable isotopic ratios of mineralized tissues from nine pigs raised on monotonous mixed C3/C4 vegetarian diets. Two sources of collagen (humerus and mandible) and two sources of apatite (humerus and enamel) were analyzed. Within each diet group, humerus and mandible collagens were found to record equivalent δ¹³C and δ¹⁸O ratios; however, enamel apatite was found to be enriched over bone apatite by 2.3‰ in carbon and 1.7‰ in oxygen. Alkaline cooking was found to slightly, but significantly increase the Δ¹³C_{collagen-diet} and Δ¹⁸O_{collagen-diet} of bone collagen. A similar trend towards enrichment was observed in bone and enamel Δ¹³C_apatite-diet and Δ¹⁸O _apatite-diet, but the differences were not significant. Observed isotopic shifts were consistent with increased nutrient utilization of the alkaline-cooked maize as compared to raw maize. In addition, a reexamination of the relationship between diet and tissue carbon isotopic values suggests that species and alimentary type should be considered when interpreting ancient diets.     

A historical review of ethnological and archaeological analyses of mortuary practice

For over a century, anthropologists have analyzed death-related phenomena to acquire knowledge concerning religion, social organization, and economic cooperation. There have been notable epistemological shifts in this inquiry by socioculturalanthropologists, with a “time lag” prior to concomitant archaeological shifts in explanation of similar phenomena. This article reviews many sociocultural and archaeological contributions to the development of a theory of mortuary practice. It is felt that although many advances in method have been made by modern archaeologists in terms of mortuary practice, they have been restricted by an exclusive British functionalist approach. Finally, it is suggested that incorporation of structuralist theory and examinations of the entire trajectory of death-related behavior may be an aid to archaeologists.     

Potential misidentification of in situ archaeological tool-residues: starch and conidia

Microscopic identification of organic residues in situ on the surface of archaeological artefacts is an established procedure. Where soil components morphologically similar to use-residue types exist within the soil, however, there remains the possibility that these components may be misidentified as authentic residues. The present study investigates common soil components known as conidia, fungal spores which may be mistaken for starch grains. Conidia may exhibit the rotating extinction cross under cross-polarised light commonly diagnostic of starch, and may be morphologically indistinguishable from small starch grains, particularly at the limits of microscope resolution. Conidia were observed on stone and ceramic archaeological artefacts from Honduras, Palau and New Caledonia, as well as experimental artefacts from Papua New Guinea. The findings act as a caution that in situ analysis of residues, and especially of those less than 5 μm in size, may be subject to misidentification.     

The survival of biochemical information in archaeological bone

The paper gives a review of the advantages of genetic information potentially available from surviving molecules (especially proteins) in bone. Survival of such information depends on degradative processes during burial. Conventional protein chemical and immunochemical investigations on various organic components remaining in buried archaeological bone are described. The results provide information on the chemistry of collagen degradation, and indicate that polymorphic macromolecules survive at too low a concentration to be easily detectable.     

Multiple osteochondromas in the archaeological record: a global review

Multiple osteochondromas is an inherited autosomal dominant condition of enchondral bone growth. The paper undertakes the first synthesis study of the 16 known cases of the condition that have been identified in the international palaeopathological record. It also includes information derived from two newly discovered cases of the disease in two adult male individuals recovered from the Medieval cemetery at Ballyhanna, Co. Donegal, Ireland. The formation of multiple osteochondromas is the best known characteristic of the disease but it also involves the development of a suite of orthopaedic deformities. These deformities, which include disproportionate short stature, inequality of bone length, forearm deformities, tibiofibular diastasis, coxa valga of the hip and valgus deformity of the knee and ankle, are discussed in relation to the archaeological cases. Numerous synonyms for the disease have been used within the various publications produced by palaeopathologists, and this can generate confusion among readers. As such, the paper recommends that in future palaeopathologists should follow the guidance of the World Health Organization and use the term multiple osteochondromas when discussing the disease.     

First results on thermally induced porosity in chlorite cooking vessels from Merv (Turkmenistan) and implications for the formation and preservation of archaeological lipid residues

Excavations at the ancient city of Merv in Turkmenistan have yielded a significant assemblage of ceramic and stone vessel fragments from contexts dating to the Sasanian and medieval periods (5th–13th centuries AD). Many of the vessel fragments are encrusted with apparent food residue deposits offering scope for organic residue analysis and the potential to compare the use of these two very different vessel types. To enable meaningful comparison we sought to establish whether the vessel stone (a talc-chlorite schist) can absorb and preserve organic residues indicative of past use. This paper reports the first investigation to address this question using standard methods for archaeological residue analysis coupled with study of the properties of the schist fabric and basic absorption experiments. The results demonstrate that heating during cooking, even at relatively low temperatures, modifies the stone microstructure by increasing its porosity. These pores enhance the absorption capacity of the schist fabric such that chlorite cooking pots can absorb and preserve sufficient organic residue to reflect the original processing of foodstuffs, as has been previously demonstrated for ceramic fabrics. Comparison of pore capacity, archaeological residue yield and experimental absorption indicates the significance of pore-size distribution for the relative retention and preservation of organic residues in these fabrics. The results of this study indicate that a wider range of archaeological material may be suitable for absorbed residue analysis than has previously been recognised. The findings also challenge previous assumptions concerning the relationship between the properties of chlorite vessels and their mode of use in Central Asia and Near East in antiquity.     

The survival of organic matter in bone: a review

If bone is considered as a composite of collagen (protein) and bioapatite (mineral), then three pathways of diagenesis are identified: (1) chemical deterioration of the organic phase; (2) chemical deterioration of the mineral phase; and (3) (micro) biological attack of the composite. The first of these three pathways is relatively unusual and will only occur in environments that are geochemically stable for bone mineral. However, because rates of biomolecular deterioration in the burial environment are slow, such bones would yield useful biomolecular information. In most environments, bones are not in thermodynamic equilibrium with the soil solution, and undergo chemical deterioration (path 2). Dissolution of the mineral exposes collagen to biodeterioration, and in most cases the initial phase of dissolution will be followed by microbial attack (path 3). Biological attack (3) also proceeds by initial demineralization; therefore paths 2 and 3 are functionally equivalent. However,in a bone that follows path 3 the damage is more localized than in path 2, and regions equivalent to path 1 may therefore exist outside these zones of destruction. Other biomolecules, such as blood proteins, cellular lipids and DNA, exist within the physiological spaces within bone.For these biomolecules, death history may be particularly important for their survival.     

The effect of a top predator on kangaroo abundance in arid Australia and its implications for archaeological faunal assemblages

The dingo has received considerable attention in the Australian archaeological literature as an agent of bone fragmentation and accumulation. Dingoes have also been studied with respect to their commensal relationship with Aboriginal people. Study has not been directed, however, to the meta-role of dingoes as prey regulators that suppress kangaroo abundance, and the subsequent impact on human subsistence that direct competition between dingoes and humans over the same animal resources could have produced. This study presents data gathered in two adjacent cultural landscapes defined by human land use, one with dingoes and one without dingoes – to illustrate the archaeological effect that dingoes may have had on human economic systems by suppressing kangaroo abundance. Live kangaroos and kangaroo skeletal remains were on average 14-fold and 32-fold more abundant in the absence of dingoes, and contemporary commercial kangaroo harvesting and sheep grazing were restricted to areas where dingoes were absent. Given the marked effects that dingoes have on contemporary kangaroo abundance and the human economy, we argue that dingoes likely shaped the human economy in the past through human–dingo competition for the same limited resources. Evidence for competition between humans and dingoes could be investigated in the archaeological record by comparing the relative frequency of prey of different body sizes, as well as the degree of fragmentation of kangaroo skeletal elements, before and after the arrival of dingoes.     

The chert from the Castelltallat Formation (south-central Pyrenees): archaeometric characterisation and archaeological implications

Chert from the limestones and marly limestones of Castelltallat Formation (Ebro Basin) was widely used throughout prehistoric times in north-eastern Iberia to produce stone tools due to its properties and accessibility. A rough estimate indicates that this rock—either as raw material or as lithic products—was distributed mainly to the north of the outcrops, over an area of 6000–8000 km². However, other rocks in the area have similar characteristics which can lead to confusion in the interpretation of its prehistoric use and distribution. In order to establish useful archaeometric criteria for differentiating this chert from other similar, the Castelltallat chert is characterised in petrographic, mineralogical and geochemical terms. The chert nodules are found to be homogenous at the macroscopic and microscopic level, with a significant presence of bioclasts, thus indicating they might be formed in a freshwater lake environment by the early diagenetic replacement of carbonates in shallow waters. The mineralogical composition is homogeneously uniform and of a flint type, characterised by an almost exclusive predominance of quartz, without any opaline phases, and a variable proportion of moganite. The iron oxide content is very low, whereas its chemical composition is unusually high in uranium which correlates positively with carbonate content and negatively with silica. Archaeometrical parameters are provided to reach a proper identification of tools knapped with this chert. This way, chert from Castelltallat Formation turns out to be a valuable lithological marker to evaluate the range of mobility of the human groups who lived in the north-eastern Iberia and their contacts with neighbouring areas.     

Experimental assessment of maize phytolith and starch taphonomy in carbonized cooking residues

Many taphonomic studies of plant microfossils, specifically phytoliths and starch, are concerned with post-depositional movement, contamination, and morphological changes due to environmental fluctuations or plant processing. Additionally, the identification of phytoliths and starches archaeologically are based on their presence or absence. This paper examines whether it is possible to identify maize (Zea mays ssp. mays) phytolith and starch abundance associated with different processing behaviors as replicated through experimentally produced cooking residues. If successful, identification of likely associated processing and taphonomy of these microfossils will allow for a more refined interpretation of plant use as it relates to timing and plant form and processing.     

Holocene sulphur-rich palaeochannel sediments: diagenetic conditions,magnetic properties and archaeological implications

Extensive aggregate extraction in the middle Trent valley, England, has revealed a sequence of Holocene palaeochannels associated with nationally important, and predominantly organic, archaeological remains. This paper reports observations of hyper-acidity (below pH 2), high natural magnetism and metallic sphaerules (framboids) in Holocene palaeochannel sediments at two sites in the middle Trent valley. These properties are associated with high natural remanent magnetism which has allowed the successful palaeomagnetic dating of palaeochannel fills at one of these sites (Hemington). These sediment properties are the result of the formation of ferromagnetic iron sulphides, including griegite, under conditions of high sulphur availability (from groundwater) in the presence of metallic ions and organic matter under low redox conditions, with later oxidation producing the extreme natural acidity through oxidation of disulphide (pyrite). These findings explain why, under certain groundwater conditions, alluvial palaeochannel sediments can carry post-depositional remanent magnetisation and be suitable for palaeomagnetic dating. The low pH may also be beneficial in the initial stage of wood preservation and if the sediments remain waterlogged, but probably not retard decomposition after drainage and acidification, a process that is increasingly being recognised as a threat to archaeological sites in wetland environments.     

Preservation potential of charcoal in alkaline environments: an experimental approach and implications for the archaeological record

Charcoalified plant material (usually wood) has been described as being inert with a high preservation potential. Although usually black on both the outside and inside, the physical and chemical properties differ as a function of temperature and time of exposure to a heat source. Post-depositional processes however may exert additional affects on charcoalified material and introduce bias into the archaeological record. This work explores the influence of alkaline conditions, often encountered in the soil environment, on the preservation potential of charcoalified material. Charcoal, experimentally produced at different temperatures, was exposed to a number of solutions of potassium hydroxide and calcium hydroxide with different pHs, to simulate exposure to alkaline soil conditions. Under these conditions chemically mediated physical interactions occur resulting in fragmentation of the charcoal samples into (very) small pieces the size of which depends upon the initial temperature of charcoalification. Moreover further interactions result in a decrease in reflectance relative to samples not exposed to alkaline conditions. Although experimentally driven the potential for physical loss of charcoal from a particular site coupled with the reduction in (expected) reflectance of any resident material, has important implications for any conclusions drawn regarding the archaeological record.     

Archaeology and integrity: The world archaeological congress as a resource for indigenous communities

Resumen El World Archaeological Congress puede servir como un recurso esencial para los grupos indígenas que deseen participar completamente en el ejercicio de la arqueología. Las experiencias de los nativos americanos con la arqueología se pueden comparar con las de otros grupos indígenas, y el código ético, del WAC ilustra hasta que punto esta organización se toma en serio su compromiso de trabajar en cooperación con las comunidades. En este artículo se presentan algunas metas que el WAC tiene que plantearse en relación con los grupos indígenas, incluyendo la educación, el establecimiento de redes de trabajo, la profesionalidad y la gestión de los yacimientos arqueológicos.

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Résumé Le congrès Mondial d'Archéologie peut être une ressource vitale pour les indigènes désireux de participer pleinement à la profession d'archéologue. Les expériences indigènes américaines avec l'archéologie sont semblables à celles d'autres groupes indigènes et le code l'éthique du WAC démontre jusqu'à quel point cette organisation est sérieuse quant au travail et à la coopération avec les communautés. Il y a plusieurs points de considération pour le WAC au sujet des peuples indigènes, tels que l'éducation, le réseau de communication, le professionalisme et la gestion des sites culturels.

     

Hunting lesions caused by osseous projectile points: experimental results and archaeological implications

The identification of projectile impact traces on archaeological faunal remains is an important issue for understanding prehistoric hunting behavior, especially in the Paleolithic and Mesolithic. From the beginning of the Upper Paleolithic in Europe, and earlier in Africa, projectiles tipped with osseous points were of great importance for subsistence; but thus far, no specific experimental reference has been developed to help identify the traces left by these points. In 2003 and 2004 two series of projectile experiments with antler points of Magdalenian design were organized, involving two ox calves and two female fallow deer as targets for bow and spearthrower shooting. The subsequent study demonstrates that positive identifications of impact traces left by osseous points can be made. The observation of 127 impact traces allowed us to distinguish three main types of traces: notches, punctures and perforations. The relationships between the nature of the impact traces and the (i) target species, (ii) characteristics of the impacted bones, and (iii) type of weapon are presented. Synthesized results are then discussed within the context of the European Upper Paleolithic and Mesolithic.     

From the modern to the archaeological: starch grains from millets and their wild relatives in China

Starch grains from 31 modern samples of millets derived from the seeds of 7 species within the genus Setaria and 2 species within the genus Panicum were analyzed to determine diagnostic morphological characteristics. Ancient starch grains recovered from a sample of broomcorn millet (Panicum miliaceum) excavated from the Cishan site (10.0-7.6 cal yr BP) in the North China Plain were then subjected to the same analyses to determine the differences in morphologies, if any, between modern and ancient samples. The data indicate that morphological features, and particularly surface and fissure features, will allow for solid identifications of ancient millet starches, while size classes will be helpful, but will not be dependable taxonomic indicators.     

Differentiation of archaeological maize (Zea mays L.) from native wild grasses based on starch grain morphology. Cases from the Central Pampas of Argentina

This paper presents, for the first time, a detailed study, from an archaeological perspective, of the morphological characteristics of the starch grains within the kernels of selected native wild grasses found in the Central Pampas of Argentina. We compared native wild grasses to maize starch grains, which can be distinguished from each other based on their size, shape and other attributes. The majority of the studied grains did not share morphological characteristics with maize starch grains. Considering this, it can be said that, if irregular and polyhedral grains with transverse or radial fissures dominate the starch assemblage, maize identification may be done on the basis of both morphology and size. Additionally, this research contributes to the characterization of the starch grains of the Panicoideae subfamily, which includes maize. Several classes of simple and compound starch grains are described and defined for native species of Pooideae, Chloridoideae, Arundinoideae, and Panicoideae subfamilies. The results obtained may constitute a baseline for the future determination of maize and wild grass use in archaeological contexts belonging to Middle/Late Holocene hunter–gatherers in the Pampas of Argentina and neighboring areas.