Amber is coveted the world over as both jewelry and a vessel for prehistoric remnants, with rarer specimens preserving ancient water, air bubbles, plants, insects or even birds.
Typically, amber forms over millions of years as tree resin fossilizes, but paleontologists have sped that up, creating amber-like fossils from pine resin in 24 hours. The technique could help reveal the biochemistry of amber as it forms, a process that otherwise would remain hidden in the fog of prehistory.
Published on Monday in the journal Scientific Reports, the results of the fast-fossilization experiment are akin to a meal made in a pressure cooker. “It’s similar to an Instapot,” said Evan Saitta, a research associate at the Field Museum in Chicago and co-author of the paper.
The recipe for synthetic amber started with pine resin from the Chicago Botanic Garden. Dr. Saitta and his co-author, Thomas Kaye, an independent paleontologist, placed half-inch sediment disks in which the resin was embedded in a device Mr. Kaye built using a medical pill compressor, air canisters and other scavenged parts.
By both heating and pressuring the samples, the researchers were trying to simulate diagenesis, the slow, wet physical and chemical transformation required before sediment consolidates into rock.
“Diagenesis is the ultimate hurdle you need to pass to become a fossil,” Dr. Saitta said. “It’s sort of the final boss.”
Some samples produced by the researchers were imperfect, but a few echoed amber’s physical properties, such as darkened coloration, fracture lines, dehydration and increased luster.
The two also realized that they had started with the wrong family of pine tree. The amber most often studied in paleontology is Sciadopitys, a group of trees whose only living relative is the Japanese umbrella pine.
Maria McNamara, a paleontologist at University College Cork in Ireland who was not involved in the study, said future experiments should test additional plant types.
“What we really want to get a handle on is which resins polymerize faster,” she said. She also pointed out that a chemical analysis of the accelerated amber was necessary to know how close — or not — it was to the real stuff. “The tree resin has survived, but we need a proper, full chemical characterization,” she said.
For all the study’s limitations, Dr. McNamara said that simulated fossilization was an increasingly important research area. Some paleontologists have recreated bone or tissue decay to explore microbial effects. In her lab, researchers have “thermally matured” specimens to investigate the preservation of biological molecules under heat.
Without such simulations, “we’re just trusting the fossil record,” she said. “Experiments help us tell fact from fiction and determine the extent to which the fossil record is lying.”
Dr. Saitta has tried other simulations. In 2018, he buried a finch in wet sediment to see how it would be compacted. That was messy and unsuccessful. But after working with Mr. Kaye on the pressure-cooker device, they had more success studying the earlier stages of fossilization of leaves, feathers and lizard feet. With those specimens, the keratin in a feather, for instance, leached away, leaving a dark melanin-like imprint similar to a fossilized feather. (At conferences, Dr. Saitta said, he likes to test other paleontologists to spot the visual difference between a simulant and a real fossil.)
In future amber experiments, Dr. Saitta aims to embed insects, feathers or plants in resin. One reason this could prove useful is that real specimens are valuable — some trade for thousands of dollars — making destructive analysis unfeasible. “A preserved insect in synthetic amber would not be precious, since it would be lab-made,” Dr. Saitta said.
The researchers also plan to adapt their technique to pressure-cook decayed organic material and simulate geological weathering. This would more realistically capture more stages of fossilization.
Looking further ahead, experimental fossilization techniques may even allow scientists to explore the fossils of the future, Dr. Saitta said. How will Anthropocene life fossilize? What would happen to tissue or bone infused with microplastic or industrial heavy metals?
We won’t be here millions of years from now to find out. But with a pressure-cooker-like device, we may get closer.
