Phosphorus is abnormally enriched in the leached zone and the surface coating, with manganese exclusively on the surface coating, demonstrating the impact of bird droppings and ‘desert varnish’ on the rocks. The petroglyphs were engraved by removing the few top millimetres of the iron oxide-rich layer and the contrast with the paler leached zone clearly showing the carved motifs. The main rock types of the Murujuga, gabbro and granophyre, have been affected by weathering consisting of a cm-thick leached zone capped by a skin of orange and red iron and manganese oxides. The work presented in this paper is underpinned by an annual monitoring study of 10 selected sites including two control sites located on Dolphin and Gidley islands and eight test sites located closer to the industrial areas. The Murujuga is a textbook example of ancient and modern times colliding as it also hosts potentially polluting, major industrial complexes such as iron ore and salt ports liquefied natural gas, liquid ammonia and ammonium nitrate plants railway lines, pipelines and rock quarries. It is Australia’s largest and most significant collection of aboriginal rock art essentially as petroglyphs, with the number estimated at more than one million engravings. The petroglyphs of the Murujuga (Burrup Peninsula and Dampier Archipelago) in Western Australia are of exceptional cultural value for the nation. Further experimental work is currently under way. Therefore, such a semi-actualistic experimental approach, when carefully designed, potentially allows testing the hypothesis that the weathering rate of the Murujuga petroglyphs is increased by local industrial air pollution. The analytical results demonstrate that it is possible to quantitatively monitor small changes caused by the weathering of gabbro and granophyre. The results show significant chemical and physical changes of the surfaces of the rock varnish after 1 month of artificial weathering. In addition, artificial rainwater that was sprinkled over the rock samples was collected and analysed by inductively-coupled plasma mass spectrometry. Mineralogical, chemical, and physical changes were qualitatively monitored by X-ray diffraction and confocal Raman spectroscopy, and quantified by colorimetry, portable X-ray fluorescence spectrometry, and micro-computed tomography. Locally acquired Murujuga granophyre and gabbro samples with natural varnish were artificially weathered for up to four months in a climate chamber under conditions that simulated 2 years of natural weathering. Here, we report on results of an accelerated weathering experiment, simulating Murujuga weather and climate conditions that was designed and performed to test whether the expected small changes in chemical, mineralogical, and physical characteristics of the rock surface can be detected and reliably quantified by various analytical means. However, the Murujuga rock art is potentially threatened by local industrial air pollution, in particular by acid rain, but unambiguous scientific evidence is still missing. Murujuga in Western Australia has the largest concentration of ancient rock engravings (petroglyphs) in the world. It is shown that an archaeological focus on interpretation-based statistics is in the absence of ethnographic detail inconsequential. Finally, the investigation of these various aspects leads to a discussion of the differences between archaeological and scientific approaches to the Dampier rock art. The classification of the petroglyphs and the technology of their creation are also canvassed. Similarly, a consideration of the size of the corpus and of the proportion destroyed by industrial development is essential to an informed endeavour of managing the monument. This information is also fundamental to the important issues of the deterioration of this monument, aspects of its preservation and of its management. In preparation for data presentation relating to the antiquity of these cultural manifestations, the lithology, weathering processes and surface accretions at Dampier are examined in detail. It therefore focuses on issues other than the subjective responses of researchers to the cultural material, presenting instead falsifiable and testable evidence about it. This paper is part of a series attempting to place the massive concentration of petroglyphs and stone arrangements in the Dampier Archipelago of Western Australia into a scientific framework.
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