Evaluating the Photoprotective Effects of Ochre on Human Skin by In Vivo SPF Assessment: Implications for Human Evolution, Adaptation and Dispersal

Ultraviolet radiation protection factors of livestock shade cloths for free-range pigs

BACKGROUND

Protection from solar ultraviolet radiation (UVR) is paramount in light-skinned pig breeds such as Yorkshire or Landrace to avoid sunburn.

OBJECTIVES

Determination of the UVR exposure of a pig and the sun protection abilities of shade cloths with different shade rates.

ANIMALS

Life-sized plastic model of a Landrace pig.

MATERIALS AND METHODS

The model was equipped with 20 UVR meters at various anatomical positions that recorded the erythemal effective solar irradiance. A turntable enabled irradiation from different directions. Solar irradiance was measured in direct sunlight as well as under three shade cloths with different shade rates (50%, 75% and 90%) and a camouflage net. The sun protection factors (SPF) were determined as the ratio of unshaded-to-shaded measurements at the same solar elevation. The exposure ratio to ambient (ERTA) was calculated for each body site with respect to ambient irradiance. It allows determination of when pigs are at risk of sunburn and protection is needed.

RESULTS

The calculated ERTA values show that some body parts may receive higher values than ambient UVR. Measurements showed that the SPF of shade cloths depends on textile denseness. Selected shade cloths reached values of 3.5 (shade rate 50%), 4.2 (75%) and 5.8 (90%). Protection by the camouflage net was poor. The highest SPF was gained on body sides where ERTA was highest.

CONCLUSIONS AND CLINICAL RELEVANCE

Shade cloths can protect all body sites effectively and vulnerable sites in particular. The results of our study enable an estimation of when pigs are at risk of sunburn and provide quantitative metrics for sun protection. This allows effective prevention of UVR-caused skin damage and secondary disorders.

Plant-based red colouration of shell beads 15,000 years ago in Kebara Cave, Mount Carmel (Israel)

Decorating the living space, objects, body and clothes with colour is a widespread human practice. While the habitual use of red mineral pigments (such as iron-oxide, e.g., ochre) by anatomically modern humans started in Africa about 140,000 years ago, the earliest documentation of the use of organic plant or animal-based red pigments is known from only 6,000 years ago. Here, we report the oldest reliable evidence of organic red pigment use 15,000 years ago by the first sedentary hunter-gatherers in the Levant. SEM-EDS and Raman Spectroscopy analyses of 10 red-stained shell beads enabled us to detect and describe the use of a colourant made of Rubiaceae plants roots (Rubia spp., Asperula spp., Gallium spp.) to colour personal adornments from the Early Natufian of Kebara cave, Mount Carmel, Israel. This adds a previously unknown behavioural aspect of Natufian societies, namely a well-established tradition of non-dietary plant processing at the beginning of the sedentary lifestyle. Through a combined multidisciplinary approach, our study broadens the perspectives on the ornamental practices and the chaînes opératoires of pigmenting materials during a crucial period in human history.

Red Balloon rock shelter Middle Stone Age ochre assemblage and population's adaption to local resources in the Waterberg (Limpopo, South Africa)

Ochre has been found at many Middle Stone Age sites throughout southern Africa. Much work has been done to document these iron-rich raw materials, their modifications and their implications for past communities' behaviours, skills and cognition. However, until recently few works focused on the Middle Stone Age Waterberg ochre assemblages. The paper presents the ochre assemblage recovered at Red Balloon rock shelter, a new Middle Stone Age site on the Waterberg Plateau. The site preserves Middle Stone Age occupations dated around 95,000 years ago. Scanning electron microscopy observations, portable X-ray fluorescence spectroscopy and infrared spectroscopy characterization document the presence of four ochre types. The MSA ochre assemblage recovered is mainly composed of specularite and specular hematite similar to the ones of Olieboomspoort and North Brabant. Microscopic observations and infrared analyses of soil sediment and of post-depositional deposits found on the ochre pieces show that this raw material specificity is of anthropic origin and not the result of post-depositional processes. Optical and digital observations of the archaeological assemblage and its comparison with a preliminary exploratory experimental one highlight the use of abrasion and bipolar percussion to process the ochre pieces at the site. The results point to the know-how and skills of the Middle Stone Age populations who inhabited the Waterberg region around 95,000 years ago. This raises the question of whether the specificities of the Waterberg ochre assemblages correspond to populations' adaptation to the local mountainous mineral resources and the existence of a regional ochre processing tradition.

Supplementary information

The online version contains supplementary material available at 10.1007/s12520-023-01778-5.

Solar Ultraviolet Radiation, Skin Cancer and Photoprotective Strategies in South Africa†

The most recent data relating to the incidence of, and mortality from, the three commonest forms of skin cancer, namely basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and cutaneous melanoma (CM), in the Black African, Colored, Asian/Indian and White population groups in South Africa are reviewed. While exposure to solar ultraviolet radiation is the major environmental risk factor for BCC in all four groups, for SSC in the White and Asian/Indian groups and for CM in the White group, this is unlikely to be the case for most SCCs in the Black African group and for most CMs in the Black African and Asian/Indian groups. Strategies for practical personal photoprotection in South Africa are discussed with particular emphasis on people at heightened risk of skin cancer including the White population group, those with HIV or oculocutaneous albinism and outdoor workers.

Pedagogical Ecology for an Alternative Sustainability: With Insights from Francis of Assisi and Contemporary Life Sciences

Sustainability is a widely discussed issue nowadays. The “human factor” appears to be the key to a suitable theory of sustainable development and, even more, to understanding the real scope of the issue at stake. We begin by highlighting that the issue of sustainability and the related ecological crisis ultimately stem from the fundamental view of the human–environment relationships. We tackle such a fundamental view from two apparently distant but converging perspectives: the one of Francis of Assisi (the patron saint of ecologists) and the one of contemporary advancements in evolutionary biology known as the “extended evolutionary theory” (EES). This will allow us to highlight how current life sciences ground a strong form of organism–environment complementarity—a core point for any allegedly comprehensive approach to sustainability and ecology. After that, we focus on recent developments in cultural evolution studies that see culture both as the driving force of (recent) human evolution and as the general context where the human–environment relationships take place and develop. Therefore, we argue that the environment exerts a powerful pedagogical influence on the human being and on humanity as a whole. We conclude by proposing a pedagogical criterion for ecology and sustainable development, according to which the modifications caused by the human being to the environment must be assessed (also) for their pedagogical import.

The ecology and bioactivity of some Greco-Roman medicinal minerals: the case of Melos earth pigments

Mineral compounds, as pigments and therapeutics, appeared regularly in the technical and medical texts of the Greco-Roman (G-R) world. We have referred to them as 'G-R medicinal minerals' and we suggest that despite their seeming familiarity, there are actually many unknowns regarding their precise nature and/or purported pharmacological attributes. Earth pigments are part of that group. This paper presents a brief overview of our work over the past twenty years relating to: a. the attempt to locate a select number of them in the places of their origin; b. their chemical/mineralogical characterization; c. the study of their ecology via the identification of the microorganisms surrounding them; d. their testing as antibacterials against known pathogens. In the process, and to fulfil the above, we have developed a novel methodological approach which includes a range of analytical techniques used across many disciplines (mineralogy, geochemistry, DNA extraction and microbiology). This paper focuses on a select number of earth pigments deriving from the island of Melos in the SW Aegean, celebrated in antiquity for its Melian Earth, a white pigment, and asks whether they might display antibacterial activity. We demonstrate that some (but not all) yellow, green and black earth pigments do. We also show that the manner in which they were dispensed (as powders or leachates) was equally important. The results, although preliminary, are informative. Given their use since deep time, earth pigments have never lost their relevance. We suggest that the study of their ecology/mineralogy and potential bioactivity allows for a better understanding of how our perception of them, as both pigments and therapeutics, may have evolved.

A global environmental crisis 42,000 years ago

Geological archives record multiple reversals of Earth's magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.

Invasive and Non-Invasive Analyses of Ochre and Iron-Based Pigment Raw Materials: A Methodological Perspective

Naturally occurring and deeply coloured iron-bearing materials were exploited very early on by human populations. The characterization of these materials has proven useful for addressing several archaeological issues, such as the study of technical behaviors, group mobility, and the reconstruction of cultural dynamics. However, this work poses some critical methodological questions. In this paper, we will review ochre studies by focusing on the analytical methods employed, the limits of non-invasive methods, as well as examples of some quality research addressing specific issues (raw material selection and provenience, heat treatment). We will then present a methodological approach that aims to identify the instrumental limits and the post-depositional alterations that significantly impact the results of the non-invasive analysis of cohesive ochre fragments from Diepkloof rock Shelter, South Africa. We used ochre materials recuperated in both archaeological and geological contexts, and we compared non-invasive surface analyses by XRD, scanning electron microscopy coupled with dispersive X-ray spectrometry (SEM-EDXS), and particle-induced X-ray emission (PIXE) with invasive analysis of powder pellets and sections from the same samples. We conclude that non-invasive SEM-EDXS and PIXE analyses provide non-representative results when the number of measurements is too low and that post-depositional alterations cause significant changes in the mineralogical and major element composition at the surface of archaeological pieces. Such biases, now identified, must be taken into account in future studies in order to propose a rigorous framework for developing archaeological inferences.

Early anthropogenic use of hematite on Aurignacian ivory personal ornaments from Hohle Fels and Vogelherd caves, Germany

The Aurignacian (ca. 43-35 ka) of southwestern Germany is well known for yielding some of the oldest artifacts related to symbolic behaviors, including examples of figurative art, musical instruments, and personal ornaments. Another aspect of these behaviors is the presence of numerous pieces of iron oxide (ocher); however, these are comparatively understudied, likely owing to the lack of painted artifacts from this region and time period. Several Aurignacian-aged carved ivory personal ornaments from the sites of Hohle Fels and Vogelherd contain traces of what appear to be red ocher residues. We analyzed these beads using a combination of macroanalytical and microanalytical methods, including scanning electron microscopy equipped with energy dispersive spectroscopy and Raman spectroscopy. We found that the residue is composed of the iron oxide mineral hematite (Fe₂O₃). Further analyses on associated archaeological sediments by X-ray diffraction revealed the absence of hematite and other iron oxide mineral phases, suggesting that the hematite residues were intentionally applied to the ivory personal ornaments by human agents. These findings have important implications as they represent evidence for the direct application of ocher on portable symbolic objects by early Homo sapiens in Europe. Furthermore, our results reveal shared behavioral practices from two key Aurignacian sites maintained over several millennia and illuminate aspects of pigment use and symbolic practices during a pivotal time in the cultural evolution of humans.

Paleoindian ochre mines in the submerged caves of the Yucatán Peninsula, Quintana Roo, Mexico

Investigations in the now-submerged cave systems on the Yucatán Peninsula continue to yield evidence for human presence during the Pleistocene-Holocene transition. Skeletal remains are scattered throughout the caves of Quintana Roo, most representing individuals who died in situ. The reasons why they explored these underground environments have remained unclear. Here, we announce the discovery of the first subterranean ochre mine of Paleoindian age found in the Americas, offering compelling evidence for mining in three cave systems on the eastern Yucatán over a ~2000-year period between ~12 and 10 ka. The cave passages exhibit preserved evidence for ochre extraction pits, speleothem digging tools, shattered and piled flowstone debris, cairn navigational markers, and hearths yielding charcoal from highly resinous wood species. The sophistication and extent of the activities demonstrate a readiness to venture into the dark zones of the caves to prospect and collect what was evidently a highly valued mineral resource.

Provenance, modification and use of manganese-rich rocks at Le Moustier (Dordogne, France)

The use of colouring materials by Neanderthals has attracted a great deal of attention in recent years. Here we present a taphonomic, technological, chemical-mineralogical and functional analysis of fifty-four manganese rich lumps recovered during past and on-going excavations at the lower rockshelter of Le Moustier (Dordogne, France). We compare compositional data for archaeological specimens with the same information for twelve potential geological sources. Morphometric analysis shows that material from Peyrony’s excavations before the First World War provides a highly biased picture of the importance of these materials for Mousterian groups. These early excavations almost exclusively recovered large modified pieces, while Mn-rich lumps from the on-going excavations predominantly consist of small pieces, only half of which bear traces of modification. We estimate that at least 168 pieces were not recovered during early work at the site. Neanderthals developed a dedicated technology for processing Mn-rich fragments, which involved a variety of tools and motions. Processing techniques were adapted to the size and density of the raw material, and evidence exists for the successive or alternating use of different techniques. Morphological, textural and chemical differences between geological and archaeological samples suggest that Neanderthals did not collect Mn-rich lumps at the outcrops we sampled. The association and variability in Mn, Ni, As, Ba content, compared to that observed at the sampled outcrops, suggests that either the Le Moustier lumps come from a unique source with a broad variation in composition, associating Mn, Ni, As, Ba, or that they were collected at different sources, characterized either by Mn-Ni-As or Mn-Ba. In the latter case, changes in raw material composition across the stratigraphy support the idea that Neanderthal populations bearing different stone tool technologies collected Mn fragments from different outcrops. Our results favour a use of these materials for multiple utilitarian and symbolic purposes.

Neuroimaging supports the representational nature of the earliest human engravings

The earliest human graphic productions, consisting of abstract patterns engraved on a variety of media, date to the Lower and Middle Palaeolithic. They are associated with anatomically modern and archaic hominins. The nature and significance of these engravings are still under question. To address this issue, we used functional magnetic resonance imaging to compare brain activations triggered by the perception of engraved patterns dating between 540 000 and 30 000 years before the present with those elicited by the perception of scenes, objects, symbol-like characters and written words. The perception of the engravings bilaterally activated regions along the ventral route in a pattern similar to that activated by the perception of objects, suggesting that these graphic productions are processed as organized visual representations in the brain. Moreover, the perception of the engravings led to a leftward activation of the visual word form area. These results support the hypothesis that these engravings have the visual properties of meaningful representations in present-day humans, and could have served such purpose in early modern humans and archaic hominins.

Cosmetic colouring by Bearded Vultures Gypaetus barbatus: still no evidence for an antibacterial function

Bearded Vultures regularly visit ferruginous springs for cosmetic purposes to obtain their reddish plumage colouration. Different hypotheses have been proposed to explain this deliberate application of adventitious colouration: (1) to signal individual dominance status; (2) to exploit an anti-bacterial effect of iron oxides or ochre to reduce feather degradation by bacteria and, in parallel (3) to enable incubating birds to transfer this protection to their developing embryos to increase hatching success. Here, we re-evaluate the antibacterial hypothesis using three experimental approaches: (a) by applying feather-degrading bacteria to stained and unstained bearded vulture feathers; (b) by assessing the antibacterial activity of ochre; and (c) by comparing the breeding success of orange individuals with pale ones. Our findings suggest that the in vitro addition of feather degrading Bacillus licheniformis to naturally stained Bearded Vulture feathers did not retard feather degradation compared to controls. Iron particles from red soil (ochre) or iron salts had no antibacterial effect on the growth of three species of bacteria (Escherichia coli, Kocuria rhizophila and Bacillus licheniformis), incubated either in the dark or under visible light. Finally, breeding success did not differ between territories occupied by pale individuals versus orange ones. These results run counter to the hypothesis that iron oxides have an antibacterial role in Bearded Vultures. The use of red soils by Bearded Vultures may function as a territorial status signal, but may also be involved in other processes, such as pair formation and the long-term maintenance of the pair bond, as suggested for the closely related Egyptian vulture Neophron percnopterus.

Striped bodypainting protects against horseflies

Bodypainting is widespread in African, Australian and Papua New Guinean indigenous communities. Many bodypaintings use white or bright yellow/grey/beige stripes on brown skin. Where the majority of people using bodypainting presently live, blood-sucking horseflies are abundant, and they frequently attack the naked brown regions of the human body surface with the risk of transmitting the pathogens of dangerous diseases. Since horseflies are deterred by the black and white stripes of zebras, we hypothesized that white-striped paintings on dark brown human bodies have a similar effect. In a field experiment in Hungary, we tested this hypothesis. We show that the attractiveness to horseflies of a dark brown human body model significantly decreases, if it is painted with the white stripes that are used in bodypaintings. Our brown human model was 10 times more attractive to horseflies than the white-striped brown model, and a beige model, which was used as a control, attracted two times more horseflies than the striped brown model. Thus, white-striped bodypaintings, such as those used by African and Australian people, may serve to deter horseflies, which is an advantageous byproduct of these bodypaintings that could lead to reduced irritation and disease transmission by these blood-sucking insects.

Ochre and pigment use at Hohle Fels cave: Results of the first systematic review of ochre and ochre-related artefacts from the Upper Palaeolithic in Germany

Though many European Upper Palaeolithic sites document early examples of symbolic material expressions (e.g., cave art, personal ornaments, figurines), there exist few reports on the use of earth pigments outside of cave art-and occasionally Neanderthal-contexts. Here, we present the first in-depth study of the diachronic changes in ochre use throughout an entire Upper Palaeolithic sequence at Hohle Fels cave, Germany, spanning from ca. 44,000-14,500 cal. yr. BP. A reassessment of the assemblage has yielded 869 individual ochre artefacts, of which 27 show traces of anthropogenic modification. The ochre artefacts are from all Upper Palaeolithic layers, stemming from the earliest Aurignacian horizons to the Holocene. This wide temporal spread demonstrates the long-term presence and continuity of ochre use in a part of Europe where it has not been systematically reported before. The anthropogenic modifications present on the ochre artefacts from the Gravettian and Magdalenian are consistent with pigment powder production, whereas the only modified piece from the Aurignacian displays a possible engraved motif. The non-modified artefacts show that more hematite-rich specular ochres as well as fine-grained deep red iron oxide clays were preferred during the Gravettian and Magdalenian, while the Aurignacian layers contain a broader array of colours and textures. Furthermore, numerous other artefacts such as faunal elements, personal ornaments, shells, and an ochre grindstone further strengthen the conclusion that ochre behaviours were well established during the onset of the Aurignacian and subsequently flourished throughout the Upper Palaeolithic at Hohle Fels cave.

UV-C as a means to combat biofilm proliferation on prehistoric paintings: evidence from laboratory experiments

A laboratory investigation of UV-C effects was conducted over a 62-h period: a much higher dose than in classic UV-C treatment was applied to five pigments and two painting binders used by prehistoric humans. Colorimetric parameters were compared to a control to see if UV-C can change pigment and binder color. Infrared spectroscopy, scanning electron microscopy, inductively coupled plasma and X-ray crystallography were also carried out to confirm colorimetric measurement. In order to understand how microorganism may physically deteriorate paintings, limestone blocks were painted and monitored until their complete colonization by algae, cyanobacteria, fungi and/or mosses. The results show that UV-C has no effect on mineral compounds. Conversely, it is noteworthy that binder color changed under both UV-C light conditions as well as in visible light. Concerning painted blocks, a fast proliferation has been observed with deterioration of the paintings. These results show the high importance of treating biofilm as soon as possible. Moreover, these findings may be a promising avenue inducing cave managers to use friendly UV-C light to treat contaminated cave paintings and also in the prevention of biodeterioration by lampenflora.

Concentrations of trace elements in human milk: Comparisons among women in Argentina, Namibia, Poland, and the United States

Human milk contains essential micronutrients for growth and development during early life. Environmental pollutants, such as potentially toxic metals, can also be transferred to the infant through human milk. These elements have been well-studied, but changing diets and environments and advances in laboratory technology require re-examining these elements in a variety of settings. The aim of this study was to characterize the concentrations of essential and toxic metals in human milk from four diverse populations. Human milk samples (n = 70) were collected in Argentina (n = 21), Namibia (n = 6), Poland (n = 23), and the United States (n = 20) using a standardized mid-feed collection procedure. Milk concentrations of calcium, zinc, iron, copper, manganese, lead, arsenic, and cadmium were determined using inductively coupled plasma mass spectrometry (ICP-MS). We used standard multiple linear regression models to evaluate differences among populations, while including infant age, infant sex, and maternal parity status (multiparous or primiparous) as covariates. Concentrations of all elements, except zinc, varied across populations after controlling for infant age, infant sex, and maternal parity. Calcium and magnesium showed more differences across populations than iron or copper. There were no significant differences among population in zinc concentrations. Mean concentrations of lead, but not arsenic, were low compared to recently published values from other populations. The concentrations of trace elements in human milk are variable among populations. Limitations due to small sample sizes and environmental contamination of some samples prevent us from drawing robust conclusions about the causes of these differences.

Patterns of change and continuity in ochre use during the late Middle Stone Age of the Horn of Africa: The Porc-Epic Cave record

Ochre is found at numerous Middle Stone Age (MSA) sites and plays a key role in early modern human archaeology. Here we analyse the largest known East African MSA ochre assemblage, comprising 40 kg of ochre, found at Porc-Epic Cave, Ethiopia, spanning a period of at least 4,500 years. Visual characterisation of ochre types, microscopic identification of traces of modification, morphological and morphometric analysis of ochre pieces and modified areas, experimental reproduction of grinding processes, surface texture analysis of archaeological and experimentally ground ochre facets, laser granulometry of ochre powder produced experimentally on different grindstones and by Hamar and Ovahimba women from Ethiopia and Namibia respectively, were, for the first time, combined to explore diachronic shifts in ochre processing technology. Our results identify patterns of continuity in ochre acquisition, treatment and use reflecting both persistent use of the same geological resources and similar uses of iron-rich rocks by late MSA Porc-Epic inhabitants. Considering the large amount of ochre processed at the site, this continuity can be interpreted as the expression of a cohesive cultural adaptation, largely shared by all community members and consistently transmitted through time. A gradual shift in preferred processing techniques and motions is interpreted as reflecting cultural drift within this practice. Evidence for the grinding of ochre to produce small quantities of powder throughout the sequence is consistent with a use in symbolic activities for at least part of the ochre assemblage from Porc-Epic Cave.

Melanoma Chemoprevention: Current Status and Future Prospects

The incidence of skin cancers, both nonmelanoma and melanoma, is increasing in the United States. The ultraviolet radiation, mainly from sun, is considered the major cause for these neoplasms. While nonmelanoma skin cancers are far more numerous, melanoma remains the most challenging. This is because melanoma can become extremely aggressive and its incidence is increasing worldwide due to lack of effective early detection, as well as disease recurrence, following both surgery and chemotherapy. Therefore, in addition to better treatment options, newer means are required to prevent melanomas from developing. Chemoprevention is a reasonable cost-effective approach to prevent carcinogenesis by inhibiting the processes of tumor initiation, promotion and progression. Melanoma is a progressive disease, which makes it very suitable for chemopreventive interventions, by targeting the processes and molecular pathways involved in the progression of melanoma. This review discusses the roles of various chemopreventive agents such as NSAIDs, statins, vitamins and dietary agents in melanoma and highlights current advancements and our perspective on future of melanoma chemoprevention. Although considerable preclinical data suggest that melanoma may be prevented or delayed by a numerous chemopreventive agents, we realize there are insufficient clinical studies evaluating their efficacy and long-term safety for human use.

How people used ochre at Rose Cottage Cave, South Africa: Sixty thousand years of evidence from the Middle Stone Age

We describe colour, hardness, grain size, geological type and surface modifications of ochre pieces excavated, first by Malan and later by Harper, from the Middle Stone Age (MSA) of Rose Cottage Cave, 96, 000 to 30, 000 years ago. Soft, bright-red shales are abundant, and most ochre has clayey or silty grain sizes. The post-Howiesons Poort layers contain the most ochre pieces, but the Howiesons Poort layers have the highest frequency of ochre per sediment volume. The pre-Howiesons Poort layers have the highest utilization rate. Use-traces include rubbing, grinding, combined grinding and rubbing, and rare instances of scoring. The processing techniques are proxies for ochre use. Rubbing transfers red ochre powder directly onto soft surfaces, such as human skin, or animal hide. This is appropriate when skin colouring and marking or skin protection (for example from sun, insects or bacteria) is the purpose. Grinding produces ochre powder that can be used for a variety of tasks. It can be mixed with water or other products to create paint, cosmetics or adhesives. Multiple uses of ochre powder and ochre pieces are therefore implied at Rose Cottage and changes through time are apparent.

Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy)

This study examines the geochemical and mineralogical variations in the ferruginous mineralisations that crop out within Grotta della Monaca, which is considered to be the most striking and best known example of a prehistoric iron mine-cave from the southern Apennines (Calabria, Italy). Previous archaeological research identified three local and distinct ancient exploitation phases of these ferruginous mineralisations: (1) an Upper Palaeolithic phase; (2) a Late Neolithic phase; and (3) a post-Medieval phase. These materials, which have various forms of complex mineralogical admixtures and range in colour from yellow-orange to red and darker brown shades, mainly consist of iron oxides/hydroxides (essentially goethite and lepidocrocite), which are often mixed with subordinate and variable amounts of other matrix components (carbonates, sulphates, arsenates, silicates and organic matter). Such ferruginous mineralisations generally correspond to geochemically heterogeneous massive dyke/vein/mammillary/stratiform facies that are exposed within the local caves along open fractures and inclined bedding planes and that partially cover cave wall niches/notches/pockets and ceiling cupolas/holes. Selected samples/sub-samples are analysed through a multi-technique approach with a handheld portable X-ray Fluorescence, X-ray Diffraction, micro-Raman and Fourier Transform Infrared spectroscope (both conventional and attenuated total reflection), which is combined with subsequent multivariate statistical analysis of the elemental concentration data. The geochemical and mineralogical results are used to individualise similar compositional clusters. As expected, the identified groups, each of which has very specific geochemical-mineralogical "fingerprints" and spatial distributions, enable us to identify the sampled ferruginous mineralisations. These specific mineral resources can be compared to similar raw materials that are found in other neighbouring archaeological sites, with obvious implications toward understanding local exploitation strategies through time and the exchanges and kinship networks of these materials.

Middle Stone Age Ochre Processing and Behavioural Complexity in the Horn of Africa: Evidence from Porc-Epic Cave, Dire Dawa, Ethiopia

Ochre is a common feature at Middle Stone Age (MSA) sites and has often been interpreted as a proxy for the origin of modern behaviour. However, few ochre processing tools, ochre containers, and ochre-stained artefacts from MSA contexts have been studied in detail within a theoretical framework aimed at inferring the technical steps involved in the acquisition, production and use of these artefacts. Here we analyse 21 ochre processing tools, i.e. upper and lower grindstones, and two ochre-stained artefacts from the MSA layers of Porc-Epic Cave, Dire Dawa, Ethiopia, dated to ca. 40 cal kyr BP. These tools, and a large proportion of the 4213 ochre fragments found at the site, were concentrated in an area devoted to ochre processing. Lower grindstones are made of a variety of raw materials, some of which are not locally available. Traces of use indicate that different techniques were employed to process ochre. Optical microscopy, XRD, μ-Raman spectroscopy, and SEM-EDS analyses of residues preserved on worn areas of artefacts show that different types of ferruginous rocks were processed in order to produce ochre powder of different coarseness and shades. A round stone bearing no traces of having been used to process ochre is half covered with residues as if it had been dipped in a liquid ochered medium to paint the object or to use it as a stamp to apply pigment to a soft material. We argue that the ochre reduction sequences identified at Porc-Epic Cave reflect a high degree of behavioural complexity, and represent ochre use, which was probably devoted to a variety of functions.