Fossilized feathers discovered 136 years ago are still revealing new secrets. Researchers found that the volcanic rock preserving the feather holds microscopic details preserved within the fossil.
The team’s research—published today in Geology—found that the feathers are preserved in zeolite, a mode of preservation that hasn’t been reported for soft tissues until now.
“Fossil feathers are usually preserved in ancient mudrocks laid down in lakes or lagoons,” said Valentina Rossi, a researcher at University College Cork and lead author of the study, in a university release. “The fossil vulture is preserved in ash deposits, which is extremely unusual. When analyzing the fossil vulture plumage, we found ourselves in uncharted territory. These feathers are nothing like what we usually see in other fossils.”
Rossi told Gizmodo in an email that the finding “expands on what it’s possible in the fossil record,” and that low temperature flows from volcanoes are “very good media to preserve soft tissues.”
The soft sediments at the bottoms of water bodies—and for that matter, non-solid land, like mudslides—can cover dead organisms, keeping them from being scavenged and preserving their remains in deep time. But preservation in zeolites—aluminum- and silicon-rich minerals that are common in volcanic settings—is a new finding, one that could mean more volcanically preserved fossils down the line.
The feather belonged to a vulture that lived in Italy some 30,000 years ago. The animal’s entire body was preserved in three dimensions, from the bird’s eyelids to the tips of its wings. Ergo: A feather fossil that is preserved down to the microscopic pigment structures in the fossil’s wing.
“We are used to [thinking] that volcanic deposits are associated with hot, fast-moving pyroclastic currents that will destroy soft tissues,” said Dawid Iurino, the study’s coordinator and a researcher at the University of Milan, in the same release. “However, these geological settings are complex and can include low temperature deposits that can preserve soft tissues at the cellular level.”
Indeed, the volatile and extreme conditions of volcanic eruptions are surprisingly good at immaculately preserving the most delicate tissues, in the right circumstances. Last month, a team of researchers confirmed that the eruption of Italy’s Mount Vesuvius in 79, which devastated and buried the nearby towns of Pompeii and Herculaneum, also turned one victim’s brain into glass—preserving the organ’s microscopic axons and neurons in a solid state.
Volcanoes spew hot gas, ash, and of course, lava when they erupt, often with fatal effects for life in their immediate vicinity. The nature of the vulture’s preservation is an encouraging sign that more extremely well-preserved fossils may lie in wait for paleobiologists to discover.
