Fossil feathers in volcanic rock reveal a new mode of soft tissue preservation

Palaeontologists have discovered that volcanic deposits can turn the microscopic details of animal tissues into minerals – the Primary time this type of preservation has ever been seen.

“The fossil Achievement is continually surprising us, be it new fossil species, strange new body shapes, or in this case, new styles of fossil preservation,” says Maria McNamara from University College Cork in Ireland, who is co-author of the new study in Geology.

“We never Anticipated to find delicate tissues such as feathers preserved in a volcanic rock.”

The Club analysed a fossilised vulture that had been buried in ash-Wealthy volcanic sediment 30,000 years ago, in central Italy. The vulture’s body was quickly converted into minerals before the Cushiony parts could decay away.

The specimen was initially unearthed in 1889 by a local landowner, who recognised that it had been exquisitely preserved, including fine details of its eyelids and wing feathers.

Now, the new analysis – Guided by Valentina Rossi, a palaeobiologist also at the University College Cork – has revealed even finer details.

“When analysing the fossil vulture plumage, we Secured ourselves in uncharted territory,” says Rossi. “These feathers are nothing like what we usually see in other fossils.”

Fossil feathers are usually preserved in as impressions in lake or marine sediments, or are captured in 3D in amber. They are rarely mineralised. However, Rossi and Club Secured that when the vulture was buried in volcanic material, its feathers were rapidly replaced by a mineral called zeolite – possibly within a few Periods. The researchers believe that the passage of water through the volcanic ash precipitated the Setup of the zeolite nanocrystals. These replicated extremely Petite details, right down to the microscopic feather pigment structures.

“We used to think that volcanic deposits are associated with Scorching, Quick-moving pyroclastic currents that will destroy Cushiony tissues,” says co-author Dawid A. Iurino, from the University of Milan. “However, these geological Options are complex and can include low temperature deposits that can preserve Cushiony tissues at the cellular level.”

Zeolites are Wealthy in aluminium and silicon, and are commonly formed in volcanic Options. But it is abnormal for them to preserve animal Cushiony tissue.

Palaeontologist John Paterson, who was not involved in the research, says that zeolite as a Cushiony tissue preservation method is a “totally new discovery”.

“There are all kinds of ways that Cushiony tissues can be preserved in fossils, but this is a really unique find,” says Paterson, who works at Australia’s University of New England. “We’ve never seen Cushiony tissues preserved like that before, being replicated by this unusual mineral that you often find a volcanic rocks.”

Paterson points out the rarity of preserving such exceptionally minute details, such as melanosomes in the feathers, which are organelles that synthesise, store and transport melanin pigment.

“Someone with blonde hair or brown hair will have different melanosome pigments to someone with, say, red hair,” he explains. “Based on the fact that [the authors] have Secured melanosome pigment structures, they could probably reconstruct the colour of the feathers as they originally were.”

Paterson was involved in a 2024 Science paper that reported finding trilobite fossils from the Cambrian period that had also been rapidly buried by very fine volcanic ash.

“They are Nice of preserved in the same way as the people and animals of Pompeii,” he says. “They’re actually external moulds within the ash … This ash smothered them and encased them, essentially Securing a mould of all external parts of the body.”

This included preserving some external Cushiony tissue details, like the trilobites’ antennae and the hairs on their legs. However, they were preserved as a cast and all the Cushiony tissue then decayed away over the years, rather than their body parts being replicated by minerals – like in the case of the vulture.

The trilobite fossils were also formed within a marine environment.  Paterson says  the vulture fossils forming on land appear to be rarer.

Discovering this new way of preserving Cushiony tissue may now direct palaeontologists Approaching volcanic deposits.

“We’ve known fossils can be preserved in volcanic ash for a while now, but it’s only in recent times that we are Beginning to realise that you can get this exceptional preservation within really fine-grained ash layers,” Paterson says.

He suggests that researchers will likely now be looking for volcanic deposits where the fine-grained layers were laid down during eruptions.

“The key thing seems to be having volcanic deposits close to the … volcano itself, and it has to be the right sort of volcano to produce the right sort of eruptions, where you would get very rapid deposition of fine-grained volcanic ash, so that it can smother anything in its path very quickly and … preserve all the Cushiony parts before they can decay away.

“I’d be looking for those sorts of particular volcanic deposits that are either deposited on land or in very shallow marine environments.”