Core-Shell Processing of Natural Pigment: Upper Palaeolithic Red Ochre from Lovas, Hungary

Characterizing paint technologies and recipes in Levantine and Schematic rock art: El Carche site as a case study (Jalance, Spain)

This paper contributes to current debates on the technologies and practices of prehistoric artists using the rock art site of el Carche (Jalance, Spain) as a case study. The site preserves both Levantine and Schematic paintings, yet poorly understood from an analytical point of view. In the past, it has even been argued how little differentiation there is between these two post-Paleolithic traditions in terms of paint composition. Our aim with this paper was to identify pigments, paint recipes and technologies and decipher the order of the superimpositions, both between Levantine motifs of different styles, and between these and the Schematic ones. To do so, we adopted a multi-stage and multi-technical analytical strategy, trying to find a balance between sound scientific investigation and impact on the art, considering the irreplaceable nature of this World Heritage rock art. As such, our approach begins with in situ non-invasive investigations using portable EDXRF, to then collect micro-samples for non-destructive analyses by means of Optical Microscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX), micro-Raman Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). One of the key highlights of these paper is the identification of up to four different paint compositions, produced with various hematite-based raw materials and different processing techniques. This variability had not been previously documented. Interestingly though, no direct correlations appear to exist between styles or sub-styles and recipes. Some of these paint mixtures were even shared by both traditions. These results are discussed in cultural terms, challenging previous interpretations suggesting a similar pigment composition between Levantine and Schematic art. Microstratigraphic analysis of the cross-sections only partially clarified the overlapping sequence unveiling the complexity of these analysis. They also revealed several degradation layers and external crusts related to rock alteration processes and biological formations. Their role in rock art conservation is also discussed.

Mammal extinction facilitated biome shift and human population change during the last glacial termination in East-Central Europe

The study of local extinction times, together with the associated environmental and human population changes in the last glacial termination, provides insights into the causes of mega- and microfauna extinctions. In East-Central (EC) Europe, groups of Palaeolithic humans were present throughout the last glacial maximum, but disappeared suddenly around 15,200 cal BP. In this study cave sediment profiles dated using radiocarbon techniques and a large set of mammal bones dated directly by AMS ¹⁴C were used to determine local extinction times. These were, in turn, compared to changes in the total megafauna population of EC Europe derived from coprophilous fungi, the Epigravettian population decline, quantitative climate models, pollen and plant macrofossil inferred climate, as well as to biome reconstructions. The results suggest that the population size of large herbivores decreased in the area after 17,700 cal BP, when temperate tree abundance and warm continental steppe cover both increased in the lowlands. Boreal forest expansion started around 16,200 cal BP. Cave sediments show the decline of narrow-headed vole and arctic lemming populations specifically associated with a tundra environment at the same time and the expansion of the common vole, an inhabitant of steppes. The last dated appearance of arctic lemming was at ~ 16,640 cal BP, while that of the narrow-headed vole at ~ 13,340, and the estimated extinction time of woolly mammoth was either at 13,830 (GRIWM) or 15,210 (PHASE), and reindeer at 11,860 (GRIWM) or 12,550 cal BP (PHASE). The population decline of the large herbivore fauna slightly preceded changes in terrestrial vegetation, and likely facilitated it via a reduction in the intensity of grazing and the concomitant accumulation of plant biomass. Furthermore, it is possible to conclude that the Late Epigravettian population had high degree of quarry-fidelity; they left the basin when these mammals vanished.

Hotter and sicker: External energy expenditure and the tangled evolutionary roots of anthropogenic climate change and chronic disease

BACKGROUND

The dual crises of climate change and chronic, or non-communicable, disease (NCD) have emerged worldwide as the global economy has industrialized over the past two centuries.

AIMS

In this synthesis I examine humans' dependence on external (non-metabolic) energy expenditure (e.g., fire, fossil fuels) as a common, root cause in these modern crises.

MATERIALS AND METHODS

Using fossil, archeological, and historical evidence I show that the human lineage has been dependent on external energy sources since the control of fire in the Paleolithic. This reliance has grown with the development of agriculture, the use of wind- and water-power, and the most recently with industrialization and the transition to fossil fuels. To place industrialization in context I develop a Rule of 50, whereby individuals in industrialized economies consume roughly 50-times more external energy and manufacture roughly 50-times more material than do hunter-gatherers.

RESULTS

Industrialization and mechanization, powered by fossil fuels, have promoted centralization and processing in food production, reduced physical activity, and increased air pollution (including greenhouse gas emissions). These developments have led in turn to NCD and climate change.

DISCUSSION AND CONCLUSION

Climate change and NCD are connected both to one another and to our species' deep evolutionary dependence on external energy. Transitioning to carbon-free energy is essential to reduce the existential risks of climate change, but will likely have only modest effects on NCD. With the impending exhaustion of oil, coal, and natural gas reserves, developing replacements for fossil fuels is also critical to maintaining our species' external energy portfolio.

Hunter-Gatherers Harvested and Heated Microbial Biogenic Iron Oxides to Produce Rock Art Pigment

Red mineral pigment use is recognized as a fundamental component of a series of traits associated with human evolutionary development, social interaction, and behavioral complexity. Iron-enriched mineral deposits have been collected and prepared as pigment for use in rock art, personal adornment, and mortuary practices for millennia, yet little is known about early developments in mineral processing techniques in North America. Microanalysis of rock art pigments from the North American Pacific Northwest reveals a sophisticated use of iron oxide produced by the biomineralizing bacterium Leptothrix ochracea; a keystone species of chemolithotroph recognized in recent advances in the development of thermostable, colorfast biomaterial pigments. Here we show evidence for human engagement with this bacterium, including nanostructural and magnetic properties evident of thermal enhancement, indicating that controlled use of pyrotechnology was a key feature of how biogenic iron oxides were prepared into paint. Our results demonstrate that hunter-gatherers in this area of study prepared pigments by harvesting aquatic microbial iron mats dominated by iron-oxidizing bacteria, which were subsequently heated in large open hearths at a controlled range of 750 °C to 850 °C. This technical gesture was performed to enhance color properties, and increase colorfastness and resistance to degradation. This skilled production of highly thermostable and long-lasting rock art paint represents a specialized technological innovation. Our results contribute to a growing body of knowledge on historical-ecological resource use practices in the Pacific Northwest during the Late Holocene.

Figshare link to figures: https://figshare.com/s/9392a0081632c20e9484.

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.