Magical reasons ancient indigenous Australians burned grass revealed

By Stephen Beech

Indigenous Australians were burning grass for magic, healing and cursing enemies at least 25,000 years ago, reveals new research.

Perfectly preserved "phytolith" plant crystals show that they were taking certain grasses into caves for ritual burning during the last ice age, say scientists.

The GunaiKurnai, an Australian Aboriginal nation, are the acknowledged traditional custodians of Gippsland and the southern Victorian Alps in southeastern Australia.

Within their territory are caves, known from 19th century ethnographic reports and oral traditions to have been the setting for magic, healing and cursing rituals by powerful medicine men and women — known as "mulla-mullung" — as well as by other spiritual practitioners.

Now archaeologists have shown that people have been visiting one of the caves, Cloggs Cave, for such activities over the past 25,000 years.

Study co-author Elle Grono said: "The Old Ancestors selected whole grasses from the wider landscape and carried them into Cloggs Cave to spread out in thin layers and burn.

"Over time, sediments covered these burned layers, preserving each layer on top of another over thousands of years."

Grono along with colleagues from Australia, France and New Zealand studied the phytoliths — microscopic silica bodies from plant tissues — recovered from buried deposits in Cloggs Cave.

The study, published in the journal Frontiers in Environmental Archaeology, was part of archaeological excavations undertaken in 2019 and 2020 that aimed to understand how people gathered plants for use inside the cave in the past.

The excavations had been requested by the GunaiKurnai Land and Waters Corporation, with representatives of the GunaiKurnai community taking part in the study design, fieldwork, interpretations and dissemination of the results.

Grono, from the Australian National University, Canberra, said: "Unlike pollen, which is dispersed by wind or insects, phytoliths mostly accumulate at the spot where a plant decays.

"No plants grow inside the cave due to a lack of light, so the phytoliths must have been carried in by people or by animals such as possums on their fur or through their scats.

"We focused on half-burned phytoliths from ashy layers, which can only have been brought in by people, as unburned ones might have arrived through either means."

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The researchers used microscopy to assign taxonomic groups to thousands of phytoliths from two pits, respectively 1.5 meters (4.9 feet) and 2.3 meters (7.5 feet) deep.

The top strata of the pits consisted of 73 thin ashy layers laid down by people between around 4,400 and 1,600 years ago, as calculated by optically stimulated luminescence and carbon dating via accelerator mass spectrometry.

Within those ashy layers, the team unexpectedly uncovered a 28-centimeter (11-inch) high standing stone, subsequently shown to have been erected in the cave by Old Ancestors for ritual purposes around 2,000 years ago.

The team found a total of 29 different types of phytoliths from several plant groups including grasses, herbs and woody plants.

They were mostly well preserved, with even the most delicate silica structures such as hair cells surviving pristine.

Up to 97% were from grasses, both from the subfamily Pooideae which prefer temperate or cool climates, and from Panicoideae which mostly grow under warm and humid conditions.

Phytoliths from the Chloridoideae family, drought-resistant grasses that grow well in warm, dry arid environments were less common, while those from woody plants and herbs were rare.

The researchers say the GunaiKurnai were "very selective" as to which types of plants they took to the cave.

They avoided diverse species from the riparian forest and open woodland found in the vicinity of Cloggs Cave before European settlement, and instead targeted grasses that would have been available a short distance away from the cave entrance.

Grono said: "The phytoliths found at Cloggs Cave were from different parts of grass plants such as stems, leaves, flowers and roots, indicating that whole grasses were brought in, including the inedible parts."

She said that, overall, nearly a fifth of the phytoliths were burned or melted.

Grono says their presence throughout the dated deposits implied that people had brought plants into the cave and burned them there over the entire time span of the past 25,000 years.

Bruno David, who co-led the excavations, said: "Their burning is consistent with GunaiKurnai traditional practices of using ash to perform magic and rituals, and also to track the footsteps of anyone coming in, including spirit-Beings.."

David, of Monash University, Melbourne, added: "Other macro-botanical evidence such as fat-smeared trimmed wooden sticks from Casuarina trees were also found in deeper and older deposits, indicating that other kinds of rituals using woody plants were also performed."