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Perth Now
10-07-2025
- Science
- Perth Now
Evidence acidic pollution is damaging ancient rock art
Industrial pollution is highly likely to be damaging ancient Indigenous rock art that has been nominated as a World Heritage site, research shows. Murujuga in Western Australia contains the world's largest, densest and most diverse collection of rock art engravings, known as petroglyphs, and some are estimated to be more than 50,000 years old. The peninsula in northwest WA near Karratha is home to two gas plants, a fertiliser plant and iron ore and salt export facilities. The industrial emissions they produce cause lower pH and higher acid levels in the local rainwater and on the rock surfaces, a study has found. An accelerated weathering experiment simulating six years of exposure to rainwater with various acidity levels found industrial emissions were already likely to be degrading the outer layer of the rocks where the petroglyphs are etched. "The rock varnish on petroglyph-bearing rocks from Murujuga is highly likely impacted by local industrial pollution, with weathering rates most likely already accelerated due to the lower pH of the rainwater," the Bonn University study said. "Furthermore, it is highly probable that weathering rates will increase further if the pH continues to decrease, as the dissolution rates of the primary phases of the varnish tended to rise at lower pH values. "The most important finding was that these dissolution rates increased significantly at pH < 5." Previous reports show acid rain with a pH below 5.6 frequently occurs on Murujuga, with an average pH of 4.6, and that the environment has become more acidic over time, the study said. Environment Minister Murray Watt announced on Wednesday he would travel to the United Nations Educational, Scientific and Cultural Organisation headquarters in France in a bid to have Murujuga listed as a World Heritage site. The site was put forward to UNESCO in 2023 but Australia's application was referred back in May. It recommended state and federal governments address concerns nearby acid emissions, including those from Woodside's Burrup gas hub, were degrading the art. Mr Watt recently gave provisional approval for a Woodside project on the peninsula to continue operating until 2070. Mardathoonera woman and Murujuga traditional custodian Raelene Cooper, who is in Paris at the UNESCO meeting, said the study showed how much danger the rock art was in. "The German researchers found that pH values below five meant an increased rate of weathering and erosion of the rocks, including increased porosity and degradation of the surface layer of the rocks," she said on Thursday. Murujuga and the surrounding islands are believed to contain more than a million petroglyphs. They depict animals, plants and human figures, and are visible due to the colour and contrast between the removed varnish layer and the underlying brighter weathered rind of the host rocks.
Jordan Times
22-05-2025
- Science
- Jordan Times
Scholar highlights Ayyubid legacy, challenges of distinguishing it from Mamluk period
The Ayyubid castle of Ajloun, located in the northwestern part of Jordan, overlooking the Jordan Valley (Photo courtesy of ACOR) AMMAN — For Professor Bethany Walker from Bonn University, it is a true challenge to differentiate some pottery objects whether they belong to Ayyubid (1171-1260) or Mamluk (1250-1517) period. Walker wants to separate two periods that are often called Ayyubit-Mamluk and belong to Middle Islamic era. "Ayyubid period was much shorter than Mamluk period," Walker said during the lecture " Jordan in the Ayyubid Age" held at the Department of Antiquities of Jordan on Wednesday, adding that if one excavates on the Mamluk site they will not find many remains older than the Mamluk period. Mamluk's powerful visual presence in Jordan also underlines Ayyubid Sultanate contribution, Walker continued, adding that Mamluks re-used Ayyubid buildings. "Vernacular buildings didn't change much from 12th until early 20th century in Jordan," Walker said, noting that to differentiate between these two periods became a challenge. The Ayyubids laid foundation for administrative buildings, fortresses and castles, as well as way stations for pilgrims and store houses for agricultural produce. They invested in network of roads and castles, reviving the world economy. One of the achievements of the Ayyubids was the beginning of the sugar industry in Jordan Valley and the Dead Sea area, where the sugar technology was brought from the Indian Subcontinent (sugar canes). "The major achievement of the Ayyubids in Jordan was economic," Walker stressed, adding that agricultural sector flourished during their reign. Rural area was economically stimulated to produce certain types of crops during that period. "The most active of the Ayyubid rulers was AlMu'azzam (1218-1227) who ruled from Damascus," Walker said, noting that in the early decades of the 13th century Karak became a scientific and educational centre. However, there are no architectural traces of these activities as no remains of madrasas and hospitals survived to our days. Al Mu'azzam built villages and the state stimulated different types of migrations to urban and rural centres. Nasser Dawoud in 1244/1245 renovate the Karak Castle, adding that palatine halls at Karak and Shobal castles represent the Ayyubid architecture. Regarding the Ayyubid bathhouse, Walker said:" It's relatively small, with three to four rooms." The Mamluks would tear down old, decrepit buildings and reuse the material for new structures, and that is one of the reasons why it is often difficult to distinguish which building belonged to the Ayyubid and which to the Mamluk period. "In some textual documentation there is evidence of these demolitions, like in chronicles, where villages around the Shobak Castle are mentioned. Here we have accounts what still functions and what is in ruins," Walker said, adding that ruins had a commercial value as a building material.
