Rock Art Conservation Research Articles

Amplifying Indigenous Australian Voices in the Conservation and Management of Rock Art

ABSTRACT Rock art is internationally recognised as a tangible connection to cultures past, whose conservation, and management programmes should be developed accordingly. When these heritage places are located within living cultural landscapes and are part of the continuing culture of First Nations people as they are in Australia, there is a fundamental requirement for programmes to be owned and implemented by the relevant communities. However, giving primacy to the voices of those with cultural authority and agency does not always amplify these efforts. To address this challenge, Traditional Owners came together, supported by a land management agency and researchers, to stage a rock art forum for Indigenous Australians in early 2023. This ground-breaking initiative is significant, because the first manual on conserving and managing rock art that gives primacy to the worldviews of Australia’s First Peoples will be an output from the forum. Past Australian publications om this subject have been authored by non-Indigenous scholars and practitioners who considered only an international framework for conserving and managing rock art as a cultural treasure. This paper considers discussions from the forum and the developing manual as shared stories of resilience to manage, protect and celebrate rock art through Indigenous-led initiatives to inform the present and prepare us for future advances in the discipline.

Ecological strategies of bacterial communities in prehistoric stone wall paintings across weathering gradients: A case study from the Borana zone in southern Ethiopia

Rock art paintings represent fragile ecosystems supporting complex microbial communities tuned to the lithic substrate and climatic conditions. The composition and activity of these microbial communities associated with different weathering patterns affecting rock art sites remain unexplored. This study aimed to explore how bacterial communities adapt their ecological strategies based on substrate weathering, while also examining the role of their metabolic pathways in either biodeterioration or bioprotection of the underlying stone. SEM-EDS investigations coupled with 16S rRNA gene sequencing and PICRUSt2 analysis were applied on different weathered surfaces that affect southern Ethiopian rock paintings to investigate the relationships between the current stone microbiome and weathering patterns. The findings revealed that samples experiencing low and high weathering reached a climax stage characterized by stable microenvironments and limited resources. This condition favored K-strategist microorganisms, leading to reduced α-biodiversity and a community with a positive or neutral impact on the substrate. In contrast, moderately-weathered samples displayed diverse microhabitats, resulting in the prevalence of r-strategist bacteria, increased α-biodiversity, and the presence of specialist microorganisms. Moreover, the bacterial communities in moderately-weathered samples demonstrated the highest potential for carbon fixation, stress responses, and complete nitrogen and sulfur cycles. This bacterial community also showed the potential to negatively impact the underlying substrate. This research provided valuable insights into the little-understood ecology of bacterial communities inhabiting deteriorated surfaces, shedding light on the potential role of these microorganisms in the sustainable conservation of rock art.

Conservation and Co-Management of Rock Art in National Parks: An Australian Case Study

Using rock art conservation as a focus, this paper outlines the levels of legislated protection afforded to designated natural and cultural areas/sites in Australia and describes the co-management approach adopted in 1998 in relation to Mutawintji National Park in western New South Wales. The park encompasses four different protection categories: a Historic Site, a Nature Reserve, a National Park, and a State Conservation Area. Known for more than a century, the Historic Site is a major area of rock art containing Aboriginal engravings, paintings and stencils. Management of the Historic Site is a key concern, given the tourist interest and associated potential for accelerated deterioration of cultural heritage. The Mutawintji Plan of Management pointed to the importance of Mutawintji for Aboriginal people to connect with the country, and the co-management model encouraged tourism development as a means of providing employment opportunities as Aboriginal guides. No special legislative requirements in relation to rock art conservation, beyond those already in existence, were applied to the co-management system. Using field knowledge involving rock art research and early guide training programs at Mutawintji and literature sources, this paper suggests possible future approaches to rock art conservation in the Mutawintji Lands.

Evaluating possible prehistoric cave art in the central Mediterranean: Analyses of pigment traces and identification of taphonomic processes at Għar Ħasan, Malta

The archaeology of the Maltese Islands, particularly the megalithic ‘temple’ structures and underground mass burial sites (hypogea) of the ‘Temple Period’ (ca. 3800 – 2300 BCE), has been the subject of considerable interest. Less is known about the prehistoric use of caves. In particular reports of prehistoric cave art at Għar Ħasan (Hasan’s Cave) have remained controversial, and have been argued to reflect an otherwise unknown pre-Neolithic occupation on the islands.Here, we report a reinvestigation of Għar Ħasan. To distinguish graffiti that have accumulated over the last century and possible older rock art, a range of non-invasive methods were used to determine the chemical properties and colour spectrum of the pigment traces: portable energy-dispersive X-ray fluorescence spectrometry (p-ED-XRF) and visible (VIS) and near-infrared (NIR) spectroscopy. In addition, pigment traces were analyzed with digital microscopy and image enhancement techniques (DStretch).Most of the previously reported cave paintings were shown to have been produced in the last century. One key panel may be older, but vandalism and other destructive processes make a definitive assessment challenging. While we therefore consider the evidence for ‘Palaeolithic’ cave art at Għar Ħasan to be inconclusive, our study also identified complex taphonomic processes that pose severe limitations on the identification of pigment via p-ED-XRF and spectroscopy and can inform and guide future initiatives for rock art conservation.

A multi-analytical evaluation of the depositional pattern on open-air rock art panels at “Abrigo del Lince” (Badajoz, Spain)

Microscopic observation correlated with chemical–mineralogical characterization was performed on pigment samples from “Abrigo del Lince” rock art site (V-IV millennium BC), in order to provide contributions to the study of prehistoric schematic art on granite in the province of Badajoz (Spain). The research objectives include the understanding of technological and cultural aspects, as well as of conservation and deterioration issues related to the pictographs. The multi-analytical approach encompasses the integration of microscopic observation, SEM–EDS analysis, micro-Raman spectroscopy, and ATR-FTIR and allowed to achieve a multispectral overview of the samples and to describe their varied composition and the alteration pattern which connects them. The main phases overlying the granitic bedrock and involved in this sequence are as follows: hematite, whewellite, and gypsum. While hematite could be stratigraphically considered the most ancient layer and assigned to the use of red ochre as a pigment, whewellite and gypsum are the main constituent of the alteration layer which forms a patina over the pictographs, due to weathering processes. Finally, the role of biofilms in rock art conservation is discussed, suggesting that, especially for what concern thin and homogenous layers of oxalates, their presence should not be necessarily considered an issue.

The State of Preservation of the Shakhty Rock Art Site and the Prospects of Its Conservation

This article deals with the preservation of the Shakhty rock art site, discovered in the Eastern Pamirs in 1958 by the leading Central Asian Stone Age researcher V.A. Ranov. The analysis of photographs taken in the Shakhty rock shelter during the 2019 survey revealed the nature of destructive processes at the site due to environmental conditions of the Eastern Pamir highland. The article integrates the results of analysis of Ranov’s archives at the Donish Institute of History, Archaeology and Ethnography of the National Academy of Sciences, Republic of Tajikistan. Thanks to Ranov’s diaries and photographs, it was possible in 2019 to assess the degree of erosion on the rock surface, and the loss of fragments of painted images over more than 60 years. Emergency areas requiring conservation efforts were identified. Principles of conservation and restoration of rock art are outlined, and an overview of techniques developed for sites of this type in the post-Soviet space in the last quarter of the 20th century is presented. State of the art conservation methods for rock art, which, in the future, can be applied for the preservation of emergency areas at Shakhty, are described. A set of measures is suggested to preserve this site.

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.

A Multi-Analytical Approach to Infer Mineral–Microbial Interactions Applied to Petroglyph Sites in the Negev Desert of Israel

Petroglyph sites exist all over the world. They are one of the earliest forms of mankind’s expression and a precursor to art. Despite their outstanding value, comprehensive research on conservation and preservation of rock art is minimal, especially as related to biodeterioration. For this reason, the main objective of this study was to explore the factors involved in the degradation of petroglyph sites in the Negev desert of Israel, with a focus on biodegradation processes. Through the use of culture-independent microbiological methods (metagenomics), we characterized the microbiomes of the samples, finding they were dominated by bacterial communities, in particular taxa of Actinobacteria and Cyanobacteria, with resistance to radiation and desiccation. By means of XRF and Raman spectroscopies, we defined the composition of the stone (calcite and quartz) and the dark crust (clay minerals with Mn and Fe oxides), unveiling the presence of carotenoids, indicative of biological colonization. Optical microscopy and SEM–EDX analyses on thin sections highlighted patterns of weathering, possibly connected to the presence of biodeteriorative microorganisms that leach the calcareous matrix from the bedrock and mobilize metal cations from the black varnish for metabolic processes, slowly weathering it.

Rock art Conservation and Tourism in Iringa Region, Tanzania

Much of the archaeological research in Tanzania over the last three decades has focused on sites that have yielded early hominin fossils and the resulting data has been analysed and discussed with the goal of generating knowledge about hominins bio-cultural evolution. Previous research focused on monumental, built heritage sites along the coast of the Indian Ocean and the interregional trade networks that existed from 1000 to 1500 A.D located along the coast of the Tanzania. This regional research prioritization in Tanzania and bias has resulted in the marginalization of some geographical regions in Tanzania from a research perspective and a resultant lack of understanding of important sites in the interior archaeological sites. Our research shifts attention from the famously well researched sites to the less investigated sites in the interior of Tanzania. We have noted that many of these sites currently face many natural and anthropogenic threats. Thus, we propose a number of sustainable management and conservation strategies to mitigate threats to these non-renewable heritage resources of Iringa Region, particularly the rock art sites. We highlight the roles of different stakeholders including the Government of Tanzania in the conservation and management of the country’s patrimonies.

Special Issue – Rock Art Conservation and Management

Special Issue – Rock Art Conservation and Management

Threshold of Weathering Needed for Fire to Erode Rock Art: Case Study of a Hohokam Petroglyph, Central Arizona, USA

ABSTRACTA Sonoran Desert petroglyph panel experienced an intense wildfire event in July 2021 that eroded the entire surface, removing the Hohokam-style rock art. Field observations during sampling in 1995 indicated that the panel: (1) was coated with a heavy rock varnish, (2) had a ‘fresh’ visual appearance, and (3) had some granite-derived sand (angular grus) at the panel’s base. Micron-scale back-scatter and nanoscale transmission electron microscopy of pre-fire samples revealed a minimal amount of decay (granite grussification): mainly minor grain-to-grain separation; minor internal dissolution; and a little feldspar grain cracking. Our basic finding is that even this minimal amount of grussification was enough to set the stage for the wildfire to erode the entire panel. Pre-fire micron-scale cracking may have enabled the fire’s steep thermal gradient to spall the surface. Panel erosion was likely enhanced by pre-existing grain-to-grain porosity to facilitate further fire-induced granular disintegration. Pre-fire nanoscale dissolution within mineral grains, formed along crystal defects, provided a weakness that then led to grain cracking of quartz and other granitic minerals. The implication for the conservation of rock art on granitic panels is worrisome, but clear and simple: condition assessments need to indicate whether any granitic sand occurs at a panel’s base. Given that many places experiencing climate change are also experiencing drought and enhanced risk from wildfire, the appropriate management recommendation would then be to remove all vegetation near the panel on a regular basis.

Efficacy of the environmentally sustainable microwave heating compared to biocide applications in the devitalization of phototrophic communities colonizing rock engravings of Valle Camonica, UNESCO world heritage site, Italy

The devitalization of lithobionts prior to their removal from engraved rocks is a common conservation practice periodically undertaken in rock art sites. In this study, we assessed in situ the efficacy of three traditional biocides and of an innovative microwave heating system, and compared different application protocols to devitalize foliose and crustose lichens and a cyanobacteria-dominated biofilm on the rock engravings of Valle Camonica (UNESCO site n.94, Italy). The analysis of their vitality and stress responses by monitoring chlorophyll a fluorescence parameters (Fv/Fm, F0, OJIP transient) showed that the common application of biocides by brush is rather ineffective, particularly in the case of the resistant crustose lichens. The heating of rock surfaces to 70 °C for a few minutes by the microwave system caused devitalization of lithobionts to a similar extent as the biocide application with cellulose poultice, which, however, introduced high amounts of chemicals in the environment. The microwave irradiation overcame any lithobiontic stress resistance and avoided useless or excessive spread of biocides, appearing a promising sustainable approach for the parallel conservation of rock art and its surrounding natural environment.

History Disappearing: The Rapid Loss of Australian Contact Period Rock Art

ABSTRACT In Australia, recent climate change has resulted in prolonged droughts, massive devastating bushfires, extreme flooding, and more frequent and intense cyclones, all of which affect archaeological and historic heritage. In this paper, we report on new research on rock art at a site called Djarrng in western Arnhem Land, Northern Territory, Australia. Djarrng was heavily impacted by Tropical Cyclone Monica in 2006. We have visited the site sporadically since 1992, most recently in September 2019. We also have photographs taken in 1979 and accessed others taken in 1965 and so are in a position to document change to rock art panels over a 54 year period. We discuss not only change at the site as a result of the cyclone but also more general changes to rock art imagery at Arnhem Land sites in the past two hundred years, as well as lessons learnt from natural disasters that could be important for future rock art conservation.

Field characterisation of rock art paintings using non-invasive reflectance spectroscopy in the search for organic paint binders at Genealogy and Stickman Rockshelters in the Weld Range (Western Australia)

This paper reports on the search for organic binder materials in rock art paintings at Genealogy and Stickman Rockshelters in Wajarri Yamaji country, Weld Range (Western Australia). Portable visible, near infrared and shortwave infrared (VNIR-SWIR) reflectance spectroscopy requires no physical sampling or surface preparation. Eleven motifs were analysed in-situ. Only one of the motifs had absorption features characteristic of organic molecular bonds and resembled hematite and blood experimental paint reference materials. Constituent hematite and clay pigment minerals defined the spectra of the remaining ten motifs. This pilot study demonstrates that non-invasive VNIR-SWIR spectroscopy is an effective field characterisation tool for assessing painted rock art motifs for constituent organic materials and mineralogy including clay minerals and iron oxides. Without the need to take samples, the technique will be invaluable for rock art conservation, and as a screening tool in the search for organic materials suited for C14 direct dating in mineral pigmented rock art paint.

Indigenous Stewardship of Decolonised Rock Art Conservation Processes in Australia

ABSTRACT Applicable to nations around the world with large corpuses of rock art and disenfranchised or disempowered First Nations peoples, efforts are being implemented at locations across Northern Australia to change this power imbalance. As the Traditional Owners of Country and the custodians of an ongoing living culture, interconnected across time and space, Aboriginal and Torres Strait Islander peoples in Australia continue to fight for control of the management and interpretation of their own heritage. With many well-meaning non-Indigenous efforts in the past forty years focused on the preservation and protection of what remains within the fabric of a site in a museum-like context, changes are now occurring in a number of locations whereby Indigenous peoples have regained control of their cultural places and are working collaboratively with archaeologists and conservation specialists to care for these valuable places. Utilising both traditional methods and modern techniques to look after both tangible and intangible values, these efforts are owned, initiated and implemented by Indigenous communities with ongoing support from specialists. Conservation programmes such as these are presented, exemplifying efforts which showcase unforeseen improvements, particularly in response to previous interventions that were imposed, unmanaged and unevaluated. This decolonising process, as defined through recent doctoral research, is forging a revitalised and shared path for all involved to follow.

Hyperspectral Imaging Techniques for the Study, Conservation and Management of Rock Art

Paleolithic rock art is one of the most important cultural phenomena in the history of mankind. It was made by making incisions and/or applying natural pigments mixed with water or organic elements on a rock surface, which for millennia has been subjected to different factors of natural and anthropogenic alteration that have caused its deterioration and/or disappearance. The present paper shows a methodology that employs hyperspectral technology in the range of visible light and the near infrared spectrum, providing a scientific and non-destructive way to study, conserve and manage such a valuable cultural heritage. Recognition of coloring matter, formal recognition of the figures, superposition of forms and documentation of the state of conservation are relevant topics in rock art, and hyperspectral imaging technology is an efficient way to study them. The aim is to establish a method of creating pigment cartography and enhancing the visualization of rock art panels. Illumination sources, spectroradiometry measurements and camera adjustments must be taken into account to generate accurate results that later will be pre-processed to derive reflectance data, and then pigment analysis and enhanced visualization methods are applied. This methodology has allowed us to obtain 76% more figures than using traditional techniques throughout the case study area.

It’s Not Gelling: Conservation Mitigation at Bonne Esperance 016 Rock Art Site, Makgabeng, South Africa

ABSTRACT South Africa is richly endowed with rock art but interest in its conservation has not been given much priority. The country has been slow in developing adequate and effective conservation protocols due to lack of research interest in conservation. There are three main challenges that affect the conservation of rock art: 1) absence of coherent monitoring systems for conservation interventions; 2) lack of local expertise in rock art conservation; and 3) limited financial resources for conservation leading to an over-reliance on donor funding. In this paper we draw from the ‘Four Rock Art Sites Conservation Project’ a Rock Art Research Institute initiative funded through the US Ambassadors fund for Cultural Preservation, and outline how these challenges have plagued conservation practice in South Africa. We highlight the positive outcomes of the project and propose recommendations’ for conservation management in South Africa.

Carnarvon Gorge: safekeeping a place and Indigenous agency within rock art research and management

One of the aspects that distinguishes the investigation and conservation of rock art in Australia, the Americas and parts of Africa from other parts of the world is the intrinsic link between rock art and living Indigenous cultures. Many Australian rock art sites benefit from the presence of a continuity of cultural connectedness. There are both challenges and advantages to these connections in relation to rock art research and site management. We discuss these by focussing on two sites located in Carnarvon Gorge in the remote Southern Central Highlands of Queensland. These sites, Art Gallery and Cathedral Cave, manifest cultural continuity, albeit with some disruptions. We show how Indigenous knowledge frameworks can be incorporated into rock art research and site management, especially for the prevention of site vandalism such as graffiti. There is a need to translate this into more robust policy design that brings Indigenous involvement to the fore. As has been argued for a number of Australian and international rock art sites, the incorporation of the Indigenous voice in site management enhances the safeguarding of the rock art for current and future generations. However, there are many challenges for Indigenous communities wanting to be more directly involved in the management of their heritage including Carnarvon Gorge, Queensland.

Engagement and Management: Developing a Monitoring System for Open-air Rock Art in the UK and Ireland

ABSTRACTNeolithic and Early Bronze Age rock carvings in the United Kingdom and Ireland represent an internationally unique rock art tradition as it is, to the best of our knowledge, the only wholly abstract global rock art tradition. This heritage resource is, however, under threat from an array of factors, such as increasing population densities and agricultural intensity. In this paper, we report on the Condition Assessment Risk Evaluation (CARE) project that had as one of its primary objectives the co-production of a user-friendly, non-invasive condition assessment risk evaluation Toolkit for gathering and organising information essential for the long-term conservation of open-air rock art. We describe the public involvement CARE process through co-experience participatory focus groups, which evaluated the Toolkit, concluding that we can have confidence in the results obtained from the public. Furthermore, the variables that form part of the Toolkit and related management recommendations are presented.

Burning Images: A Critical Review of Rock Art Conservation in Zimbabwe

Rock art is the most easily accessible of archaeological material. In Zimbabwe, there are thousands of sites, mostly in open-air environments which can be accessed and enjoyed by many people without any restrictions. Yet, rock art is also easily damaged and therefore requires conservation. Social, political and economic challenges in the last two decades have had profound effects on the conservation status of this particular cultural heritage. This paper examines the state of conservation of rock art, conservation approaches and challenges in Zimbabwe. It also discusses possible solutions especially as the country is making frantic efforts at international re-engagement. The story of rock art conservation in Zimbabwe is similar to what is happening in many neighbouring developing countries such as Kenya, Uganda and South Africa. Therefore, the discussion in this paper also informs on general issues in rock art management and conservation in Africa.