Pottery wall thinning as a consequence of increased maize processing: a case study from central New York

The histories of maize in northeastern North America are not well understood at the subregional level. The complexity of formation processes for various lines of evidence for maize use requires the application of many analytical methods and techniques to produce data on subregional maize histories. The present analysis uses bulk δ¹³C values on directly dated charred encrusted cooking residues to provide the first direct correlation of water-based maize cooking to trends in pottery wall thinning. The results add to the growing body of evidence for the history of maize use in central New York.     

Short-chain n-alkanes (C16–20) in ancient soil are useful molecular markers for prehistoric biomass burning

The incorporation of plant biomass into soil usually leads to long-chain n-alkanes with a relative predominance of odd carbon numbered homologues. Contrastingly, an increase in short-chain even carbon numbered n-alkanes was found in charred biomass with progressing temperatures. We applied lipid analysis to buried ancient topsoils that contained charred organic matter and to corresponding control soils, which were characterized by a lighter color and lower contents of charred materials. Commonly, the proportion of lipid extracts was found to be lower in the ancient soil than in the control samples, which indicated an enhanced degradation of organic matter, e.g., by thermal degradation. All samples displayed a particular pattern of short-chain and even carbon numbered n-alkanes (maximum at n-C₁₆ or n-C₁₈). The ratios CPI (carbon preference index) and ACL (average chain length) for the investigated soil samples matched the ratios found for maize and rye straw charred at 400 °C or 500 °C, respectively. These molecular ratios indicate the presence of charred biomass. The predominance of short-chain and even carbon numbered n-alkanes was a result of thermal degradation of biomass. The degradation products were preserved in ancient soils and could be applied as molecular markers in archaeological or palaeoenvironmental research.     

Stable carbon- and nitrogen-isotope ratios and electron spin resonance (ESR) g-values of charred bones: changes with heating and a critical evaluation of the utility of g-values for reconstructing thermal history and original isotope ratios

Changes in the stable carbon and nitrogen isotope ratios of modern bone samples heated to a variety of times and temperatures were used to determine the effect of heating on isotope ratios and the retention of organic matter in charred bones. For organic extracts produced by slow demineralization in weak acid, δ¹³C values were unchanged, while δ¹⁵N values increased by up to 5‰ and were primarily determined by heating temperature. Changes in the electron spin resonance (ESR) g-value of whole bone and organic extracts were also measured. For organic extracts from charred bones, the g-value was well-correlated with δ¹⁵N and temperature, suggesting that g-values could be used to estimate the charring temperature and original δ¹⁵N values of charred bones. Thus, g-values from demineralized extracts could be very useful in forensic investigations where it would important to reconstruct the thermal history of burned bones. Isotope ratios and g-values of demineralized extracts from four prehistoric components at three sites that produced cremated human bone were used to test whether the same approach can be applied to archaeological materials. While carbon isotope ratios of the prehistoric samples were similar to those of uncharred specimens, nitrogen isotope ratios were increased and the g-value corrections for nitrogen isotope ratios were not effective.     

Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

DNA analysis in charred grains of naked wheat from several archaeological sites in Spain

In the present work we attempt to recover endogenous ancient DNA from cereal grains preserved under different conditions: charred, partially charred and waterlogged. A total of 126 grains from naked wheat and 18 from barley from different sites on the Eastern Iberian Peninsula ranging from the beginning of agriculture in the region to the turn of the Common Era, were studied. Two different extraction protocols were used, a standard phenol–chloroform method and a silica-based DNA extraction procedure implemented for artificially charred seeds. Amplifications were directed to three markers: the large subunit of ribulose 1,5 biphosphate carboxylase (rbcL) and the microsatellite WCT12 in the chloroplast genome and the x and y subunits of the high molecular weight glutenin gene (Glu-1) in the nucleus. The first two were used to assess the preservation status of the samples, while with the third we tried to identify the wheat grains at species level. It was possible to obtain eleven positive amplifications in 8 partially charred seeds but only two amplifications of the Glu-1 gene from a single sample of the Early Bronze age were genome-specific. Different contamination sources were identified and reported. Cloning and alignment of sequenced clones showed a correspondence of the amplified fragment to modern wheat D genome haplotypes. This result suggests that the sample corresponds to hexaploid wheat (Triticum aestivum L.), thus being the first ancient DNA evidence to date for the cultivation of hexaploid wheat in the prehistoric agriculture of the Iberian Peninsula. Moreover, obtained results highlight contamination problems associated to the study of ancient archaeobotanical charred seeds suggest that the combination of a silica-based extraction method together with the amplification of specific targets is a good strategy for recovering endogenous ancient DNA from this kind of material.     

Paleodietary implications from stable carbon isotope analysis of experimental cooking residues

The regional timing of maize introduction in eastern North America is a long-standing topic of archaeological interest. Most recently, Morton and Schwarcz [2004. Paleodietary implications from stable isotopic analysis of residues on prehistoric Ontario ceramics. Journal of Archaeological Science 31, 503–517] investigated the timing of maize introduction in Ontario through isotope analysis of charred cooking residues adhering to the interior of prehistoric ceramic containers. They interpret their results to suggest maize was incorporated into diets after A.D. 600. We assess their approach and conclusions with stable carbon isotope assays on three sets of experimental cooking residues, evaluating the variable combustion of carbon fractions, contributions of fats and carbohydrates, and the contribution of total carbon. We also undertake multiple resource modeling of two part food mixes with green maize and maize flour. Our results suggest that systematic under representation of maize can result depending on residue composition and that some prior knowledge of C3 plant and animal contents is necessary to interpret stable carbon isotope values on cooking residues. We question the independent use of stable carbon isotope analysis of charred cooking residues as a viable technique for extracting paleodietary information.     

Temperature,compression and fragmentation: an experimental analysis to assess the impact of taphonomic processes on charcoal preservation

This paper explores how mechanical properties of different South Asian tree taxa might influence charred wood fragmentation and the composition of charcoal assemblages retrieved from archaeological contexts. The dataset is composed of selected plant species that were collected in Gujarat (Northern India) in September 2007 as part of the North Gujarat Archaeological Project. The taxa analysed represent the most common wood species found in the arid thorn scrubland formation in South Asia and are among the most abundant identified in Neolithic and Chalcolithic archaeological sites in this area. The specimens have been measured and subsequently charred at three different temperatures, under constant conditions. Afterwards, their resistance to compression has been measured on two planes, parallel and perpendicular to the direction of fibres, using a Hounsfield 5-kN machine. The tests were performed in order to understand the different response to compressive stress of wood that has been subject to a range of thermal degradations. The standardised treatment applied to the samples has permitted the comparison of results and the delineation of simple correlations and divergences among the species analysed. Furthermore, the utilisation of a relatively simple operating protocol easily allows the addition of further data in the future. The applied protocol was specifically designed to answer archaeological questions. Therefore, even though from a material science point of view some of the measurements were not taken according to the prevailing standard procedures, it offers valuable data for anthracological research applied to archaeology in arid zones.     

An experimental study of bean and maize burning to interpret evidence from Stillhouse Hollow Cave in western North Carolina

ABSTRACT

Test excavations in a small rockshelter in the mountains of North Carolina uncovered remains of a hearth containing carbonized twigs, maize kernels, bean cotyledons, animal bone, and the fragments of a single ceramic vessel dating to approximately AD 1350. Experiments in carbonization of maize kernels and beans and involving fire-extinguishing conditions indicate that the burnt seeds recovered from the hearth were probably dry when burned, that the fire may have been smothered or doused, and that the remains may represent an offering of dry seeds, rather than food refuse, similar to that observed historically among the Cherokee.     

Crop Fertility Conditions in North-Eastern Gaul During the La Tène and Roman Periods: A Combined Stable Isotope Analysis of Archaeobotanical and Archaeozoological Remains

ABSTRACT

Considerable archaeobotanical datasets describe cereal cultivation in north-eastern France, from the Iron Age to the Roman period. This study aims to complement these by using stable isotope analysis on charred cereal grains. Soil fertility was investigated through δ¹⁵N and δ¹³C analyses of 1480 charred cereal grains, dated from the Late La Tène to the Late Antiquity periods. In the Île-de-France, charred grain Δ¹³C values suggested good hydric conditions, with drier episodes in the 1st and 3rd century AD; while in Champagne, the lower Δ¹³C values for spelt reflect the lower water holding capacity of the chalky soils. A wide range of cereal δ¹⁵N values (0.8–8.7‰) implies a wide range of soil fertility conditions. Jouars-Pontchartrain and Palaiseau (Île-de-France) yielded the highest cereal δ¹⁵N values, whereas Acy-Romance (Champagne) delivered among the lowest. From these three sites, the δ¹⁵N values of red deer bone collagen were used to estimate the reference δ¹⁵N values for unmanured plants. Unlike in Acy-Romance, there were significant differences in Palaiseau and Jouars-Pontchartrain, indicating that the cultivated cereals inherited their high δ¹⁵N values from manured soil. At Jouars-Pontchartrain, the δ¹⁵N value (almost 9‰) suggested a high trophic level manuring source, possibly from pig and/or human faeces.     

Archaeobotanical inference of Bronze Age land use and land cover in the eastern Mediterranean

Charcoal and charred seeds at five Bronze Age archaeological sites discern ancient land use in the eastern Mediterranean. Seed frequencies of orchard crops, annual cereals and pulses, and wild or weedy plants are used to characterize plant utilization at different archaeological sites on the island of Cyprus, in the Rift Valley of Jordan, and in the Jabbul Plain and along the upper Euphrates River valley in Syria. Seed to charcoal ratios provide proxies to determine the relative usage of dung versus wood for fuel across the ancient Mediterranean landscape. Greater charcoal and lower charred seed values are interpreted to represent a wooded environment, while higher amounts of charred seeds and minimal wood charcoal suggest a much great use of dung as a fuel source. Interestingly, Politiko-Troullia (Cyprus, Cypriot archaeological sites are, by convention, named for the nearest modern village (Politiko), followed by an italicized toponym (Troullia) referring to the plot of land that incorporates the site) has the lowest seed to charcoal ratio, suggesting its residents primarily burned wood and that the landscape surrounding Troullia remained relatively wooded during the Bronze Age. In contrast, villagers at Tell el-Hayyat (Jordan) utilized a mixture of wood and dung, in contrast to Tell Abu en-Ni’aj (Jordan), and especially Umm el-Marra and Tell es-Sweyhat (Syria), where inhabitants relied solely on dung fuel. Comparative analysis and interpretation of seed and charcoal evidence thus illustrates the variety of fuel use strategies necessitated by the dynamic and diverse Bronze Age landscapes of the Eastern Mediterranean.     

IDENTIFICATION OF JET AND RELATED BLACK MATERIALS WITH ESR SPECTROSCOPY

Recent studies of the thermal histories of archaeological materials with electron spin resonance (ESR) spectroscopy have been extended to black materials encountered in archaeology and in the conservation of antiquities. The ESR parameters of jet. charcoal and lampblacks are reported and comparisons made with a range of related materials Discrimination and characterization is achieved by simultaneous consideration of the three main parameters of the ESR signal due to radical carbon. This study is the first attempt using ESR spectroscopy to discriminate between jet and related coal-like substances.     

Stone-boiling maize with limestone: experimental results and implications for nutrition among SE Utah preceramic groups

Groups living on Cedar Mesa, SE Utah in the late Basketmaker II period (Grand Gulch phase, AD 200–400) were heavily maize-dependent, but lacked beans as a supplemental plant protein, and pottery vessels for cooking. Common occurrence of limestone fragments in their household middens suggests 1) limestone may have been used as the heating element for stone-boiling maize and 2) this practice might have made some maize proteins more available for human nutrition. Experiments examined these possibilities; results indicate that stone-boiling with Cedar Mesa limestone creates an alkaline cooking environment suitable for nixtamalization of maize kernels, and that maize cooked in this fashion shows significant increases in availability of lysine, tryptophan, and methionine. Archaeological limestone fragments from a Grand Gulch phase site show amounts of fragmentation and changes in density consistent with repeated heating. While not conclusive, these data indicate that further research (e.g., examination of archaeological limestone fragments for maize starch grains or phytoliths) is warranted. It is suggested that greater attention be paid to archaeological indications of stone-boiling with limestone among maize-dependent but pre-pottery societies.     

The Preservation and Interpretation of δ34S Values in Charred Archaeobotanical Remains

The measurement of sulphur isotope (δ³⁴S) values in charred plant remains has the potential to inform understanding of the spatial configuration and ecology of crop production. We investigated the effects of charring, manuring, oxidation and anaerobic soil conditions on modern cereal grain/pulse seed δ³⁴S values, and assessed the effect of chemical pre‐treatment on charred modern and archaeobotanical grain/seed δ³⁴S values. We used these results to interpret δ³⁴S values in archaeobotanical material from Neolithic Çatalhöyük. Our results suggest that δ³⁴S values can be reliably preserved in charred grain/seeds but are subject to influence by anaerobic soil conditions, the effect depending on the timing of flooding in relation to S assimilation.     

Back from burn out: are experimentally charred grapevine pips too distorted to be characterized using morphometrics?

This article examines the impact of charring on the possibility to characterize grape pips, at compartment (wild versus domesticated) and cultivar level, using morphometrics. Two morphometric methods have been used, one based on linear measurements (traditional morphometrics) and one on elliptic Fourier transforms (EFT; morphogeometrics). Charring experiments were performed using a laboratory muffle furnace and various charring conditions. Despite the strong impact of heating, results showed that wild and domesticated Vitis seeds can be reliably discriminated using both traditional morphometrics and morphogeometrics, even when charring has been done at high temperature (450 °C). The characterization of charred pips at cultivar level using EFT is very powerful when the seeds are charred at 250 °C, but the risk of misclassification is, as expected, higher at 450 °C. Results suggest that the characterization at cultivar level should only be attempted with large assemblages of well preserved archaeological pips, and only after a first classification at compartment level. Our approach was applied on a case study of two assemblages of waterlogged and well preserved charred pips from the archaeological site of Lattara. The results are consistent both between the two morphometric methods and between waterlogged and charred remains.     

Selective woodland exploitation for charcoal production. A detailed analysis of charcoal kiln remains (ca. 1300–1900 AD) from Zoersel (northern Belgium)

A detailed study of charcoal burning activities has been made for the Zoersel forest (Northern Belgium) based on an inventory of charcoal kiln remains, the analyses of wood charcoal and other charred botanical macroremains and radiocarbon dating of 10 of these kilns. Age determination of the youngest kilns was refined by dendrochronological analysis of trees growing on top of these kiln sites. The results show that, although many kilns were found, charcoal was produced in Zoersel only at certain moments during late and post-medieval times suggesting that charcoal burning was not a part of the regular management practice of these forests. The wood used for the production of charcoal mainly consists of taxa of alluvial (alder) forests while the kilns are situated on sites that currently are rather dry, with an oak dominated vegetation. For the older kilns, this contrast could be explained by an important change in local soil conditions. The younger kilns may be related to the conversion of alder woodland to grassland in the lower parts of the domain, with the kilns being constructed in the nearby dryer woodland areas.     

Archaeological and Historical Materials as a Means to Explore Finnish Crop History

ABSTRACT

In Northern Europe, barley (Hordeum vulgare L.) has been cultivated for almost 6000 years. Thus far, 150-year-old grains from historical collections have been used to investigate the distribution of barley diversity and how the species has spread across the region. Genetic studies of archaeobotanical material from agrarian sites could potentially clarify earlier migration patterns and cast further light on the origin of barley landraces. In this study, we aimed to evaluate different archaeological and historical materials with respect to DNA content, and to explore connections between Late Iron Age and medieval barley populations and historical samples of barley landraces in north-west Europe. The material analysed consisted of archaeological samples of charred barley grains from four sites in southern Finland, and historical material, with 33 samples obtained from two herbaria and the seed collections of the Swedish museum of cultural history.

The DNA concentrations obtained from charred archaeological barley remains were too low for successful KASP genotyping confirming previously reported difficulties in obtaining aDNA from charred remains. Historical samples from herbaria and seed collection confirmed previously shown strong genetic differentiation between two-row and six-row barley. Six-row barley accessions from northern and southern Finland tended to cluster apart, while no geographical structuring was observed among two-row barley. Genotyping of functional markers revealed that the majority of barley cultivated in Finland in the late nineteenth and early twentieth century was late-flowering under increasing day-length, supporting previous findings from northern European barley.     

Under Pressure: A Laboratory Investigation into the Effects of Mechanical Loading on Charred Organic Matter in Archaeological Sites

The present publication investigates what happens to archaeological sites when they are built over. Focus is put on the degradation of charred organic materials by static loading. It is assumed that materials lose archaeological value if their fragments become too small to be recovered, or too distorted to be classified at species level. Several charred ecofacts of a few millimetres in size (wood fragments, hazelnut shells, and seeds) have been selected and subjected to individual particle strength tests. Assemblages of these particles have also been compressed one-dimensionally and scanned at several stages of testing using laboratory based X-ray microtomography. Microscopic damage by splitting or crushing is found to be limited at the macroscopic yield stress. It initiated at stresses less than 80 kPa for the weakest assemblages, and in all cases at stresses below 320 kPa. (80 kPa represents the load of a 6 m high sand embankment on soft soil that has half-settled underneath the groundwater table, while 320 kPa corresponds to stresses applied beneath the pile foundation level of high-rise buildings.) Sand seeded with charred particles has also been tested to illustrate the beneficial effect of embedment of charred particles in sand during static one dimensional loading.     

Improved methodology for extraction and amplification of DNA from single grains of charred wheat

Comparisons were made between two commonly used methods for the extraction of ancient DNA from charred plant remains. Using artificially charred wheat seeds, we show that silica-binding is the most efficient method for extraction of DNA. We describe a improved silica-binding procedure, including pre-incubation with N-phenacylthiazolium bromide and increased washing of bound DNA, which yields amplifiable DNA from seeds heated at 200 °C for up to 8 h, conditions which promote the formation of Maillard products which often copurify with aDNA and inhibit subsequent PCRs. We believe that this method will be effective in ancient DNA extraction with most types of charred archaeobotanical material. Both cold- and hot-start PCR procedures gave good amplicon yields with extracts prepared in this way, but cold-start PCRs also resulted in synthesis of short artefact products. Addition of bovine serum albumin to PCRs, an inert carrier substance thought to enhance amplification efficiency by binding contaminants, had no advantageous effect and in fact reduced amplicon synthesis.     

MACROBOTANICAL ANALYSIS OF TWO HOPEWELL MOUND SAMPLES FROM THE MANN SITE (12PO2) IN INDIANA

Abstract

The Mann site (12PO2), most noted for its large Hopewellian mound complex, is a little studied but significant archaeological site in southwestern Indiana. Non-mound habitation areas at both the Mann and nearby Mann phase Grabert site were the sole source of archaeobotanical information for these sites prior to the current macrobotanical analysis of two newly available and fairly large (55–60 g of charred material each) samples collected from Mann site mound pit features. Analysis of the macrobotanical material from these pits, in the context of what is already known from both the Mann and Grabert sites, provides additional evidence that plant resources were being used in the Mann phase subsistence system consistent with interregional Hopewellian influences. Data indicate that the inhabitants were using some form of seed storage and may have been participating in non-burial-related ceremonial feasting.     

Reconstruction of the Late Glacial and Early Holocene landscape and human presence in Lubrza,Western Poland,on the basis of multidisciplinary analyses

This paper presents the results of a multidisciplinary study that combines archaeological and palaeoenvironmental research to examine the relationship between environment and human activities in Western Poland during the Late Glacial and Early Holocene. The study area lying within the young moraine landscape produced several Late Palaeolithic and Early Mesolithic sites, varied in terms of size and function. Analyses of pollen, plant macro-remains and molluscs accompanied by geomorphological investigations and supported by series of radiocarbon dates have enabled a detailed reconstruction of environment. It has shown that despite climatic fluctuations during the Allerød and Younger Dryas, the studied area provided favourable conditions for hunter-gatherer occupation. The presence of micro- and macroscopic charcoal, charred particles of herbaceous plants and charred mosses in peat deposits of former water bodies evidence various activities carried out by Federmesser and Swiderian groups, for example setting up camp-fires and deliberate burning of the local marsh vegetation. Usewear analyses of flint implements have revealed further traces of diversified human activities undertaken at examined sites. Most importantly, this article focuses on plant-based craft activities undertaken by hunter-gatherers, about which little has hitherto been known.