The volcanic millstones from the archaeological site of Morgantina (Sicily): provenance and evolution of the milling techniques in the Mediterranean area*

The Morgantina archaeological area, inhabited from the Early Bronze Age, had its widest expansion from the fifth to the first century bc . The volcanic millstones found at Morgantina fall into three different groups on the basis of the milling technique: (i) saddle querns (known from the Middle–Late Bronze Age and Iron Age); (ii) rectangular hopper‐rubbers (Olynthian) millstones, the invention of which dates to the fifth century bc ; and finally (iii) Morgantina‐type rotary millstones (starting to be used from the fourth to the third century bc ). In order to determine the provenance of the raw materials (lavas) used for all these millstone types, we collected 38 very small rock samples for thin‐section modal mineralogy, petrography and major trace element composition. The results have contributed to classifying different lithotypes and distinguishing between provenance from Etna and the Hyblean Mountains, the two volcanic areas respectively north‐east and south‐east of Morgantina. Saddle querns are made of tholeiitic basaltic andesites from the Hyblean Mountains and transitional basalts, mugearites and hawaiites from Etna. The variety of sources of portable saddle querns, mostly used in households, indicate that there was no general preference for specific quarrying sites. By contrast, the rectangular hopper‐rubber and the Morgantina‐type millstones, which document the period of Morgantina's greatest prosperity, are almost completely made of hawaiites from Etna. The use of a specific lithotype (i.e., Etna hawaiite) for the more efficient rectangular hopper‐rubber and rotary millstones could be linked to the fact that these mills may have been operated in business establishments. It is worth noting that the Gornalunga river was, in antiquity, a waterway joining Morgantina to the final stretch of the Simeto river and then the Ionian coast. The best candidate areas for the millstone hawaiite quarrying sites from Etna are the far south‐western sectors of the volcano, along the Simeto Valley (i.e., the ‘Piano Provenzana’ Formation) or the inner suburb of present‐day Catania (i.e., the ‘Pietracannone’ Formation). The very efficient Morgantina‐type rotary millstones spread during the reign of Hieron II of Syracuse (275–215 bc ) in eastern Sicily and met the need for grinding large quantities of cereals during a relatively peaceful time and a period of agricultural development.     

Different Preparation Techniques – Similar Results? On the Quality of Thin‐Ground Sections of Archaeological Bone

Palaeohistology as a valuable diagnostic instrument is dependent on the production of high‐quality thin‐ground sections from dry bone. The objective of this study was to consider technical differences and assess the qualitative outcomes of five techniques for preparing thin‐ground sections from dry archaeological bone. Established techniques with long follow‐up times and excellently documented results were compared with simpler and cheaper time‐saving techniques. Evaluations were made of the quality of thin sections obtained by one classical machine‐based embedding technique, two revised versions of the same technique, one manual moulding technique based on Frost's rapid technique and one manual hybrid technique. Five osteological specimens of differing quality were prepared following the manuals for these five techniques and examined microscopically with respect to a list of standardised histological and diagenetic parameters. Alterations in the specimens attributable to preparation effects were recorded, and observations were scored with reference to three criteria: section quality, technical quality and staining. The results show that embedding techniques are to prefer. Superglue should not be used as a mounting or embedding medium. Manual grinding comes with several limitations, and machine cutting and grinding are preferred. Haematoxylin staining can be successfully applied to embedded specimens, giving more information on microscopic diagenetic processes. A stepwise manual for a revision of the classical embedding technique is presented. The time required for producing sections using classical embedding techniques is shortened from 6 weeks to 3.7 days by refining the preparation/polymerization processes involved with no loss of osteological data. Copyright © 2014 John Wiley & Sons, Ltd.     

A comparative experiment in the consolidation of cremated bone

This experiment assessed whether consolidation of cremated remains facilitated cross‐sectioning and grinding, which often are required for microstructural analyses such as the histomorphometric estimation of age and the examination of pathological lesions. Green, bovine femoral diaphyses were cremated at three temperature ranges (346–357°C; 610–755°C; 684–838°C) in an electric furnace and then consolidated with Acryloid B‐72 or Butvar B‐98 using simple brushing and immersion techniques. After consolidation was complete, bone pieces were cross‐sectioned and ground to a thickness of 100–120 μm. Results indicate that specimens treated with Acryloid B‐72 are harder and stronger than Butvar treated and untreated control specimens. Acryloid B‐72 is, therefore, recommended for the consolidation of cremated remains in preparation for microstructural analysis. Copyright © 2004 John Wiley & Sons, Ltd.     

A Quasi Non‐destructive Microsampling Technique for the Analysis of Intact Glass Objects By Sem/edxa

A novel sampling technique for the analysis of glass is described, which involves the removal of minute particles from an object with a diamond‐coated file, followed by energy‐dispersive X‐ray analysis in the scanning electron microscope (SEM/EDXA). The particles are fixed to adhesive carbon discs and carbon coated without grinding or polishing. Mean compositions are determined for 10 arbitrarily selected particles above a minimum grain size of 150 mm and normalized to totals of 100%. Tests were carried out on two standard soda–lime–silica glasses of well‐characterized composition, using two files of different grade. The analyses showed good agreement with the accepted values of all elements. Although the precision is somewhat reduced, this highly portable and quasi non‐destructive microsampling procedure provides almost the same information as that gained from samples embedded and polished in the normal way. Its application is thought to be especially useful for the investigation of intact glass objects and ceramic glazes.     

Manual for the Preparation and Staining of Embedded Natural Dry Bone Tissue Sections for Microscopy

In the last decade, the use of light microscopy has been firmly established for the investigation of exhumated human bone tissue. As a rule, these remains cannot be decalcified; thus, they are most commonly prepared for microscopic analysis as ground thin sections. These ground sections are of great value in diagnosing disease, in estimating age or in assessing taphonomic alteration. As bone is sometimes fragile and can be damaged by the grinding process, the specimen is occasionally supported by an embedding medium. In contrast to the vast amount of research conducted on embedded and unembedded unstained bone material, the use of histological stains on undecalcified dry bone tissue has been long neglected. In this article, a new method for embedding, sawing and grinding dry bone tissue is presented. The produced sections are subsequently stained with haematoxylin. The results show that even ground sections of fragile bone can be made in a quick and easy manner. Staining these sections enhances the envisioning of micro‐architecture and taphonomical processes. In addition, the sections stay open for inspection under polarized light. The results were consistent throughout the used bone material. To keep the method as accessible and comprehensive as possible, a step‐wise manual is provided. An additional troubleshooting paragraph discusses the most often encountered problems and provides solutions. Copyright © 2011 John Wiley & Sons, Ltd.     

EXPERIMENTAL EVALUATION OF SAMPLE‐EXTRACTION METHODS AND THE POTENTIAL FOR CONTAMINATION IN CERAMIC SPECIMENS*

Contamination of ceramic specimens resulting from sample‐preparation techniques has the ability to confound efforts of chemical characterization. Primary contamination, identified by significant concentrations of one or more elements, is easily identified. Secondary contamination, resulting from undetected elements influencing detected elements, is more difficult to identify. Evaluation of six powder‐extraction techniques identifies variable effects of contamination. Extraction by drilling carries the highest risk of contamination. The grinding of specimens with silicon‐carbide wheels may artificially deplete abundances by introducing Si and C. Grinding specimens in an agate mortar and pestle is found to be the technique least likely to result in contamination effects.     

Necessary for Life: Studies of Ancient and Modern Grinding Stones in Highland Ethiopia

Ethnoarchaeological research combined with morphological analysis of modern and ancient grinding stones was completed in 2013 and 2014 as part of the Eastern Tigrai Archaeological Project (ETAP), based in the Gulo Makeda region of northern Ethiopia. Research focused on investigating the cultural context of grinding, grinding stone morphology, and use-surface area employing low power use-wear analysis of grinding surfaces. In the Gulo Makeda region today, men manufacture grinding stones and women use them in food processing for many hours per day. While grinding, relationships are formed and maintained with other women, and archaeological evidence suggests that women were grinding together in the past. It was discovered through interviews that distinctive grinding surfaces are preferred for processing different cereals based on grain size. Rough surfaces are used to process larger grains such as imported Near Eastern barley (Hordeum vulgare), wheat (Triticum spp.), maize (Zea mays), and the African domesticate sorghum (Sorghum bicolor), while fine/smooth surfaces are used for smaller, locally domesticated African grains including finger millet (Eleusine coracana) and t’ef (Eragrostis tef). Comparing ethnoarchaeological data with evidence of different use-surfaces on ancient Mezber grinding stones suggests that both locally domesticated and imported grains have been processed in the region for thousands of years. Interpretations are made about the use of grinding stones in the past through analogy, supported by evidence of ancient stone tool morphology and surface wear. The archaeological record at the pre-Aksumite site of Mezber indicates that grinding stone sizes have changed through time, with larger grinding surface areas likely reflecting the need for the production of greater amounts of flour.     

ARCHAEOMETRIC STUDY OF PROTOHISTORIC GRINDING TOOLS OF VOLCANIC ROCKS FOUND IN THE KARST (ITALY–SLOVENIA) AND ISTRIA (CROATIA)*

This paper presents the results of the archaeometric study of 30 grinding tools found in the Karst plateau (an area that spreads from the northeastern border of Italy to Slovenia) and in the Istria peninsula (Croatia). The petrographic and geochemical characteristics of the artefacts indicate that most of them would be made of trachytic volcanites extracted from the Euganean Hills, near Padua (Veneto). It is known that trachytic rocks from this area had been widely exploited in northern Italy during protohistoric times, but these data considerably enlarge the area of diffusion of saddle‐querns made of these rocks, extending it to Istria. Additionally, the likely provenance from Mount Etna of few other pieces of mugearites and hawaiites represents a new element, to be fully evaluated in the context of trans‐Adriatic exchange/trade connections. Analytical data and possible archaeological inferences are presented in detail in the text.     

Investigating the presence of ancient absorbed organic residues in groundstone using GC–MS and other analytical techniques: a residue study of several prehistoric milling tools from central California

Analysis of absorbed organic molecules in groundstone could provide a valuable means to study resource use and processing in antiquity. The following study analyzed extracts from the surfaces of several central California milling tools to assess whether organic residues remained from prehistoric resource processing. It also sought to determine which source identification methods are likely to be successful at providing information about the type, or even the specific identify, of resources that were processed. Lipids (primarily fatty acids) were analyzed using GC–MS and the presence of phenolic compounds was assessed with UV-Vis spectroscopy. Milling surfaces were compared to previously broken surfaces from the same tool with the assumption that both surfaces had been exposed to similar post-depositional conditions. Results supported the presence of ancient residues in milling tools. A higher concentration of fatty acids was recovered from milling surfaces than paired broken surfaces. Furthermore, measurable amounts of azelaic acid (an oxidation product of some unsaturated fatty acids) were present in most milling surfaces, but not in broken surfaces. However, results also indicated that environmentally absorbed lipids formed a significant portion of the total lipid content. Thus, it is suggested that future analyses employ a biomarker approach, rather than criteria based on ratios of common fatty acids, to identify sources of organic residues in prehistoric milling tools.     

Millet and sauce: The uses and functions of querns among the Minyanka (Mali)

The central role of grinding activities in the dietary practices of traditional agricultural populations can be approached from an ethnoarchaeological point of view. The comparison of ethnographic references raises the question whether the function and the socioeconomic context in which grinding slabs are used allow to assess issues related to conclusions drawn from archaeological contexts. Our discussion is based on the analysis of the manufacturing of grinding slabs, their use cycles and their social status in several Minyanka villages (Mali), providing useful references when examining the way in which archaeologists explain and interpret technological, functional and spatial observations. The typological and technical evolution and variability of querns results from a combination of several factors determined by the available raw materials, the skill of shaping techniques, the organisation of manufacturing and the transference of the function of grinding tools. But these factors alone cannot explain the encountered range of variation. Our study thus emphasises the very role of cultural aspects within these temporal and regional developments, and the impossibility of dissociating the use of a quern from its socio-economic context.     

Seeing red: the use of Congo Red dye to identify cooked and damaged starch grains in archaeological residues

Starchy plant foods are significant in the diet of almost all peoples. Archaeologically, however, preservation of such plants is limited, and direct evidence of plant use by past people is also rare. Although starch grains can be preserved on artefacts used to process starchy plants, it is very difficult to identify grains damaged by processing methods such as milling or cooking. We present a method for identifying such damaged starch grains using Congo Red staining to identify cooking or milling activities in the past subsistence behaviour of Aboriginal people of southeast Queensland, Australia.     

The paleolithic site of Longwangchan in the middle Yellow River,China: chronology,paleoenvironment and implications

The Longwangchan Paleolithic site, situated on the Yellow River terraces in the Hukou area, Shaanxi province, China, was found in 2003–2004, and two areas (Localities 1 and 2) of the site were excavated in 2005–2008. Abundant stone artifacts including microliths, a grinding stone fragment and a shovel, with some animal bones and shells, were recovered from Locality 1. In this study, the cultural deposits from Locality 1 were dated using radiocarbon and optical dating techniques, and the sediment properties of the deposits were analyzed. The results show that the age of the deposits ranges from 29 to 21 ka and most of them were deposited between 25 ka and 29 ka. This indicates that corresponds to late Marine Isotope Stage (MIS) 3 and early MIS 2. During the human occupation period, the climate in this area became colder and drier. Sediments from beds where the grinding slab and the shovel were found were dated to ∼25 ka, which is the oldest among the grinding stones found in China. The microliths and the grinding stone are important evidence for an incipient socio-economic process that eventually led to the regional transition from hunting-foraging to farming.     

从“研”到“砚”——论砚台形制的最初演变

砚是根据中国传统书写和绘画的特有需要产生的。它的历史可以追溯到新石器时代,前身是原始研磨器,而砚最初的汉字表示也并不是"砚"字,而是"研"字。古代文献以及出土砚墨实物材料都表明,从"研"到"砚"的过程正对应了东汉时期砚台形制的最初演变,这种演变与墨的形制改变有着直接联系。     

Chemical Analysis of Starch‐Like Mineral Crystals to Eliminate Misidentification in Ancient Residue Research

To clarify issues involved in problematic identification of ancient starch granules, we investigated suspected granules found in residues from a Neolithic grinding stone in north‐east China. The chemical compositions of suspected granules and modern starch granules were tested via SEM–EDS. The results show that the elemental composition of the suspected granules mainly comprises O, S and Ca, which is similar to the composition of calcium sulphate, but quite different from that of real starch granules, which show high levels of C and O, with very low level of other elements. The findings in this study act as a warning that tiny mineral granules may be misidentified as starch, and also indicate that the method of SEM–EDS can be useful to confirm the nature of suspected granules in ancient starch analysis.     

A functional analysis of grinding stones from an early holocene site at Donghulin,North China

The processes that led to the transition from small mobile groups of hunter-gatherers in the Late Pleistocene to sedentary communities of the Early Holocene in north China are poorly understood. The Donghulin site in Beijing was occupied at the onset of the Holocene, and excavations have revealed a rich archaeological record for investigating the changing subsistence strategies during this transitional period. A functional study of two grinding stones (a slab and a handstone) near a burial dated to 9220–8750 cal BC at Donghulin investigated the range of plants exploited during this early occupation period. Starch residues indicate that the grinding stones were used for processing plants, and confirm processing of acorns, which is consistent with the incidence of oak in the pollen record. The usewear, with only rare patches of developed polish, suggests that plant parts of low silica content were processed, although usewear on the handstone suggests processing of two or more plant taxa. The results suggest that the use of grinding stones to process plant foodstuffs, particularly acorns, may have played a major role in the subsistence strategy during the transitional period to sedentism and agriculture in some parts of north China.     

西周倗国墓地绿松石珠微痕的数码显微镜分析

为有效揭示史前和历史时代早期出土玉器的加工痕迹,了解古代机械加工的起源和演变过程,选择西周倗国墓地出土的一枚穿孔绿松石珠,在带有景深扩展技术和三维图像重建功能VHX-500K型数码显微镜下进行微痕分析。发现其表面的打磨痕迹和孔壁上钻孔形成的多圈平行螺旋纹皆十分清晰。结合现代绿松石打磨的模拟实验和前人的工作,认为该枚绿松石珠表面打磨的工具应为一种机械转动磨盘,其具备粗磨和细磨两个功能。有关磨料的颗粒甚粗,其尺寸远大于现代细磨盘的磨料颗粒度。至于珠上的穿孔为对钻贯通,推测为空心管钻配合解玉砂高速旋转而成。这是国内首次将数码显微镜的景深扩展和三维重建技术应用于微痕分析,其研究成果可为古玉的科学鉴定,从加工工艺角度提供重要的信息。     

EFFECTS OF MILLING: A POSSIBLE FACTOR INFLUENCING THE DURABILITY OF HISTORICAL MORTARS

In their literary texts, some classical Roman authors such as Gaius Plinius Secundus and Marcus Vitruvius Pollio stress the importance of milling when preparing mortars. Following these indications, this work describes the effects of milling between lime (calcium hydroxide) and clay brick powder before and after the addition of water. Starting and resulting materials were investigated by XRPD, SEM/EDS, differential scanning calorimetry and thermogravimetry (DSC/TC), colorimetry, densimetry and porosimetry. Prolonged milling changes the mineralogy of the starting materials and increases their reactivity. The final lime pastes, starting from materials milled for varying periods of time, had different mineralogical and physical characteristics. These results may help to clarify the reasons for the marked differences in durability of some historical mortars.     

Front and Back Covers,Volume 28, Number 5. October 2012

Front and back cover caption, volume 28 issue 5 Front cover THE CRISIS IN MALI. Malian refugees are seen at the Mbera refugee camp in eastern Mauritanian, Mbera, Mauritania, 17 July 2012. At that point, roughly 92,000 refugees had arrived in the camp. Estimates are that nearly half a million Malians have been displaced from their homes this year with many refugees having also fled to Burkina Faso and Niger. Photo taken by award‐winning photographer, Lynsey Addario ( http://www.lynseyaddario.com ). Back cover TOURISM: WORK VS LEISURE A tourist from Hong Kong photographs a young Mursi woman with lip‐plate in her lower lip. Tourists queue up orderly for each to take their turn photographing the wonders of Mursi culture. The image demonstrates the complexity of tourist encounters, and the multifaceted aspects of leisure and work. The Mursi prepare for their visitors well ahead of touring cars arriving at their settlements. They make themselves up and imitate the kinds of working activities (e.g. grinding) they know from experience will fascinate and elicit a response from tourists. Tourists typically ask the Mursi for permission to photograph the process and, occasionally, join in themselves with the Mursi in their ‘work’. In this sense, the Mursi imitate ‘traditional’ sociality as they simulate their own working activities for tourists who supposedly spend their leisure time in Mursiland. As Tamàs Règi argues in this issue, instead of seeing leisure as a fixed human condition within one society, anthropologists might approach it, rather, as a process that evolves at the interface between different societies that meet. In this way, leisure is a constantly developing practice in cross‐cultural encounters.     

Functional analysis of stone grinding and polishing tools from the earliest Neolithic of north-western Europe

This reconstruction of grinding, pounding, hammering and abrading activities in the Early Neolithic of north-western Europe (Linearbandkeramik and Villeneuve-Saint-Germain cultures, 5100–4700 BC) is based on the study of 1289 sandstone tools from 17 sites located in the main Paris basin river valleys (Aisne, Eure, Marne, Oise, Seine, Yonne). An original method of functional identification was elaborated, relying on observation of use-wear with a stereoscopic microscope (under120×). Identification of traces of use relied on an experimental referential of 92 samples. These include (1) grinding cereals, (2) pounding temper, colourants and various plants, (3) shaping mineral, vegetal and animal objects by polishing (schist, limestones, bone, antler, wood), (4) softening skin. A significant observation concerns the use of small handstones for grain dehusking and larger handstones for grain grinding. Recycling is a widespread feature, with multipurpose handstones and frequent reuse of lower grinding tools for obtaining colourants. A change in the function of tools can also be observed between the Linearbandkeramik and the Villeneuve-Saint-Germain.     

The Ore‐Dressing Grindstone Called a ‘Quimbalete’: a Mechanics‐Based Approach

The ‘quimbalete’ is a kind of grindstone used notably in Potosi (Bolivia) during the Spanish conquest of South America. It was used to grind pieces of ore gravel from centimetric sizes to the size of sand. Its physical functioning, as well as the reason why this strictly Andean tool occupied a central place in a mainly European production chain, have never been addressed. This study is aimed at answering these questions as a result of physics‐based modelling. After introducing the historical context, we address geometrical and physical parameters relevant for understanding how this oscillating grindstone was used and what one can expect in terms of grinding. Then, a suitable approach for estimating the yield makes use of the modern industrial empirical estimator: the ‘power index’. We offer our conclusions about the position of this tool, which appears as an ideal intermediate tool between the roughening process of the ore at the centimetre scale, and the suitable size for the material to be sorted by the subsequent methods in the chain (such as washing), which involve sandy‐sized grains. The study also shows how classical physics can help in addressing questions concerning minerallurgy.