Best known as the backdrop to Hollywood movies Lawrence of Arabia (1962) and The Martian (2015), the rocks of Wadi Rum are now coming under scrutiny of a different kind. A multidisciplinary team of scientists is carrying out fieldwork to understand the damage caused to the region’s ancient rock art by modern gunfire.
We identified several key factors that predict the extent of gunfire damage, including the prior condition of the rock and the weaponry itself.The Wadi Rum World Heritage site in the Middle Eastern country of Jordan is famous for its stunning sandstone formations and ancient rock art. Having survived up to 3,000 years exposed to the elements, the charismatic engravings of ibex, cheetahs, and hyenas (all of which are now extinct in this area) have most recently been used for target practice, and bullet damage is unfortunately now widespread. Thankfully, the modern inhabitants of the region have made significant strides toward protecting their stone heritage by outlawing the use of firearms within the protected area. Locals have also established educational and tour guide training programs with Jordanian and international universities to better serve this World Heritage Site. It is their commitment and stewardship that allowed this research to take place.
Our research team visited the area in September 2018 to assess the extent of gunfire damage. We drew from our diverse range of backgrounds, including geomorphology, archaeology, and even zoology, and we deployed a suite of methods to understand how modern bullet damage differs from more natural weathering processes.
Importantly, we identified several key factors that predict the extent of gunfire damage, including the prior condition of the rock and the weaponry itself. We hope this research will inform the conservation strategies of rock art sites specifically, as well as strategies for other Middle Eastern heritage sites caught within conflict zones.
The Valley of the Moon
This Thamudic petroglyph of an ibex goat (800 to 2,000 years old) displays significant impact damage. Credit: Lisa Mol
Wadi Rum (“the Valley of the Moon”), located in southern Jordan, was awarded United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage status in 2011 on the basis of its outstanding natural and cultural landscapes. The spectacular sandstone formations responsible for Wadi Rum’s characteristic Martian red hue date from the Early Ordovician (~450 million years ago), and they form important rock shelters and excellent canvasses for petroglyphs.
Humans occupying the region for the past 12,000 years have documented their own presence on these rock surfaces, including texts in such ancient languages as Thamudic and Nabataean. In addition, rare Arabic scripts that predate the Koran exemplify the evolution of written language in the region. Older engravings, created as far back as 3,000 years ago, include scenes of fauna, hunting, and daily life in prehistoric times.
Bedouin communities remain in the valley to this day, spread across a small number of villages and tented camps. Increasingly, they share this space with tourists seeking out desert camping, camel safaris, and, most significantly, the ancient rock art.
Using a combination of in situ techniques, photogrammetry, and archaeological analysis, we aim to uncover the physical, as well as the social, impact of gunfire on stone heritage.Unfortunately, the same Bedouin groups have, in the past, caused considerable damage to the region’s petroglyphs. Firearm ownership is widespread, and evidence of this is pockmarked across the landscape. Rock art appears to have been particularly affected, with animal petroglyphs a specific focus of target practice for the purpose of gun maintenance or simply for sport.
This practice has now halted because of a combination of the site gaining UNESCO World Heritage status and an improved awareness of the cultural value of rock art, as well as the economic benefits associated with tourism. However, appreciable damage from the preceding decades not only detracts from the aesthetic value of the rock art but also raises challenges for its long-term conservation.
Our research team has now set its sights upon documenting and describing the impact of gunfire on these valuable surfaces and on the long-term consequences of arms use on heritage sites more broadly. Using a combination of in situ rock deterioration measurement techniques, photogrammetry, and archaeological analysis, we aim to uncover the physical, as well as the social, impact of gunfire on stone heritage.
Photogrammetry data collection on bullet impacts in the heat of the desert (left). Bullet holes mar the rock art on the boulder shown at left (right). Credit: Lucy Clarke Tracing Damage in the Field
To collect preliminary data, the team traveled to Wadi Rum in September 2018. Since the site achieved UNESCO World Heritage status in 2011, target practice has thankfully shifted to rock surfaces containing no petroglyphs, located outside of the protected area. This provides us with an ideal natural experiment, in which we identified bullet impacts spanning a range of well-constrained dates across the same Umm Ishrin sandstone formation. We set out to trace bullet damage across the decades and with increasing firepower while paying particular attention to potential subsurface degradation that has previously gone unnoticed.
The team collects data in the field, obtaining multiple photographs for the photogrammetric reconstructions (left) and using equipment to measure the hardness and porosity of the rock surface (right). Credit: Lucy Clarke
Our team took a three-pronged approach, exploiting the latest advances in 3-D surveying and geomorphological techniques and our diverse academic backgrounds:
characterizing affected and nonaffected surfaces using rock deterioration methodologies more commonly applied to natural weathering processes such as thermal- and salt-related deterioration using 3-D photogrammetric techniques (making measurements from photographs) to reconstruct the surface morphology of rock art faces and to quantify impact size volumetrically gathering local knowledge of the impacts and the opinions of Wadi Rum village inhabitants toward ballistic impacts and rock art protectionTo determine the state of the rock surface (the degree of weathering), we measured the rock surface characteristics indicative of a rock’s response to environmental stress. We measured rock surface hardness (Equotip portable hardness testers), saturation (Protimeter moisture meters), and porosity (TinyPerm 3 handheld air permeameters). In addition, the entire team carried out rock deterioration surveys to gain a consistent qualitative assessment of rock art deterioration in relation to ballistic impacts.
A detailed 3-D photogrammetric digital model is generated by taking multiple overlapping photographs with a digital camera. Three sites of bullet impact are located in the top left-hand corner of the rock face. The 3-D model is available free to download here. Credit: Charlotte Brassey Preliminary Findings
We identify three potential risk factors that predict the severity of rock deterioration associated with ballistic impact:
Consolidation of the Rock Surface Prior to Impact. When weathering has already badly damaged rock surfaces, bullets punch through deteriorated regions until they reach more intact rock. Deeper zones of rock deterioration are therefore associated with greater penetration of bullets. In some instances, millennia of exposure and movement of moisture within the rock can lead to deposition of minerals at the rock surface, producing a hardened crust across the rock face. Bullets typically fail to penetrate these surfaces as deeply, but they do leave behind an extensive fracture network across the surface.
Angle of Impact. Where a bullet is fired straight at the rock surface, there is a clear impact point with a circular impact cone penetrating into the surface. If a bullet hits a rock surface at an angle, the impact resonates diagonally through the rock surface, damaging a much larger surface area and destabilizing the surface in the direction of the angle of impact. On the basis of our field observations, we hypothesize that angle of impact is an important factor in determining surface removal patterns and associated subsurface damage. These observations are therefore used to direct our continued work and to systematically address the role of angle of impact in rock deterioration under controlled conditions.
Powerful modern weaponry appears capable not only of penetrating farther into a given surface but also of pulverizing the material surrounding the impact.Firepower. Our field observations indicate a proportional increase in the extent of ballistic impact zones over time. We suggest that this may correlate with weaponry, associated with a transition from early 20th century Mauser M4 and comparable rifles to the Kalashnikovs and AK-47s now widely available across the Wadi Rum region. Powerful modern weaponry appears capable not only of penetrating farther into a given surface but also of pulverizing the material surrounding the impact. This behavior is not observed in earlier impact features.
Next Steps and Potential ImplicationsThe work we report here represents the first steps toward understanding the impact of conflict on rock deterioration and thus damage to stone heritage more broadly. Unfortunately, this is a growing issue in conflict zones, where immovable (built) heritage sites are not only caught in the crossfire but also may be deliberately targeted. Most recently, the deliberate destruction of sandstone built heritage by the Islamic State of Iraq and Syria (ISIS; sometimes referred to as Daesh) has caused global outrage.
Moving forward, it is essential that initiatives to stabilize and either conserve or restore damaged heritage are grounded within a detailed understanding of the mechanisms and extent of stone damage. Our ongoing research will therefore lay the groundwork for understanding the broader consequences of targeting heritage with firearms. This work will be continued and expanded by our recently funded research for the Leverhulme Trust, in which we will quantify bullet damage to stone using a controlled range-based experimental protocol.
AcknowledgmentsThe fieldwork was made possible by the Leverhulme Trust (grant RPG-2017-408), the Manchester Metropolitan University GCRF Seed Fund (grant ID 95016), and University College London’s Knowledge Exchange and Innovation Fund (grant KEI2018-01-06R). We also greatly benefited from the expertise of the rock art rangers in Wadi Rum, who were funded by the U.S. Agency for International Development’s Sustainable Cultural Heritage Through Engagement of Local Communities Project (SCHEP). We extend our profound thanks to the Hashemite Kingdom of Jordan, the Aqaba Special Economic Zone Authority, and the leadership of the Wadi Rum Protected Area for permission to conduct research in the valley.
Author InformationLisa Mol (lisa.mol@uwe.ac.uk), Geography and Environmental Management, University of the West of England, Bristol, U.K.; Charlotte Brassey, School of Science and the Environment, Manchester Metropolitan University, U.K.; Lucy Clarke, School of Natural and Social Sciences, University of Gloucester, Cheltenham, U.K.; Kaelin Groom, School of Geographical Science and Urban Planning, Arizona State University, Tempe; and Rachel King, Institute of Archaeology, University College London, U.K.
11 April 2019: The article was updated to reflect that this damage was done historically and is no longer occurring today.
from Eos https://eos.org/project-updates/in-the-crosshairs-ancient-rock-art-under-fire?utm_source=rss&utm_medium=rss&utm_content=in-the-crosshairs-ancient-rock-art-under-fire
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