Newswise — Researchers at Flinders University have employed subterranean visualization and aerial inspections to peer into floodplains in the Red Lily Lagoon vicinity of Western Arnhem Land in Northern Australia.

These pioneering techniques demonstrated how this crucial topography in the Northern Territory underwent changes when ocean levels escalated roughly 8,000 years ago.

Their finding reveals that the sea had reached this presently inland area, which holds significant ramifications for comprehending the archaeological history of Madjedbebe—the most ancient archaeological site in Australia.

The results also offer a novel approach to interpreting the rock art in the area, which is acknowledged worldwide for its importance and unique style.

Through scrutinizing how sediments, presently interred beneath the flood plains, altered as ocean levels surged, the scientists can discern how the metamorphosis of Red Lily Lagoon led to the expansion of mangroves that have sustained flora and fauna in an area where ancestral Indigenous rock art is sited. This shift has, in turn, nurtured an ecosystem that has influenced the motifs and creatures depicted in the antique rock art.

In their report published today in the scientific periodical PLOS ONE, the investigators assert that alterations to the environment at the lagoon are mirrored in the rock art because the artwork displayed fish, crocodiles, and birds when the floodplain metamorphosed to sustain freshwater ecosystems for novel species.

Dr. Jarrad Seri Knowles, Senior Author and Research Associate in the College of Humanities, Arts, and Social Sciences at Flinders University, states that the cartography fundamentally alters our archaeological comprehension of the breathtaking topography in Arnhem Land.

"This is a pivotal topography for comprehending the initial human habitation of Australia. Our reconstruction of Red Lily Lagoon enables proficient anticipatory modeling of significant cultural sites and furnishes an essential technique to interpret the existence and origin of Indigenous cultural material." Dr. Jarrad Knowles added.

"The chronology of rock art corresponds with the wider environmental changes that we know occurred in this terrain. This is perceptible through transformations in subject matter depicted in the art, like the sizeable macropods, and the emergence of estuarine animal species such as fish and crocodiles in the artwork. The incorporation of freshwater species, including fish and birds, is present in the most contemporary artistic genres of this vicinity, and this mirrors the stages of environmental modification when freshwater floodplains constituted the terrain." Dr. Jarrad Knowles further explained.

"Consequent to the outcomes of this research, all Pleistocene sites in western Arnhem Land were proximal to the ocean and, hence, mangrove swamps at some juncture during the transformation of the landscape. This holds significant ramifications for the paleogeographic context of these sites, which must be taken into account while interpreting changes in stone artefacts, food sources, and the isotope composition of materials from this epoch of the initial Australians." Dr. Jarrad Knowles concluded.

Associate Professor Ian Moffat, a co-author of the study, opines that Electric Resistivity Tomography (ERT) is an expeditious, economical, and non-invasive methodology that can chart extensive stretches of the Australian terrain to comprehend their antique history more competently.

"We are displaying how ERT information can be employed to formulate topographic models that are valuable in comprehending established locations and foreseeing concealed archaeological sites. We have established that the terrains of this vicinity can be mapped resourcefully using non-intrusive techniques. This holds significant ramifications for discovering new sites but also for constructing a more intricate understanding of the regional topography and its effect on earlier human conduct." Associate Professor Ian Moffat further elaborated.

"Red Lily Lagoon holds exceptional archaeological importance in Arnhem Land as it lies at one of the farthest points to the east of the East Alligator River floodplain, where the present-day river and the Arnhem Plateau produce a substantial boundary between the low-lying floodplains and the sandstone highlands. These highlands have been inhabited by humans for more than 60,000 years and are the sites of numerous significant locations, including some of Australia's most emblematic rock art panels."

Co-author and Traditional Owner Alfred Nayinggull emphasized the significance of this research, saying, "We aspire for individuals to comprehend and acknowledge what took place many thousands of years ago in the past."

The new PLOS ONE paper “Reconstructing archaeological palaeolandscapes using geophysical and geomatic survey techniques: An example from Red Lily Lagoon, Arnhem Land, Australiais will be available at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0283006.

Journal Link: PLoS ONE