Jurassic Park at the Synchrotron SOLEIL
What do SOLEIL and the cinema have in common?
As the third part of the Jurassic World film series was released in cinemas, we invited you to go back to the origins of the saga through research carried out at SOLEIL.
The exceptional preservation of inclusions in amber (insects, plants, etc.) has been the subject of many fantasies, particularly the possibility of extracting the DNA of extinct organisms. Although it is now known that ancient DNA does not remain in amber, the processes behind its degradation, as well as that of the organisms themselves, remain unknown.
In early June 2022, scientists from IPANEMA and SOLEIL used the PUMA beamline to decipher the preservation processes in amber, comparing fossil insects with modern insects embedded in fresh tree resin. In particular, the researchers studied fossil flies and mosquitoes trapped in 40 million-year-old Baltic amber. Their aim: to describe the early mechanisms associated with fossilisation in amber.
2025: a look back at this research
Fossilized mosquitoes trapped in amber, shimmering golden hues, and a source of DNA that could bring dinosaurs back to life... This is the spectacular fantasy that the "Jurassic Park" saga has etched into the collective imagination. But we now know that the precious amber casing doesn't preserve DNA at all. Worse still, sometimes it doesn't even preserve the insect itself—just an empty mold of its shape, with the entire organism having vanished.
Paleontologist Pierre Guériau has taken on the mission of understanding the phenomenon of insect preservation in ancient resins. This preservation is uneven: sometimes certain organs are preserved, sometimes only the cuticle, and sometimes... nothing at all. His research focuses on modeling, using "modern" samples. These samples consist of fruit flies (Drosophila), well-known insects that are commonly used as models, encased in resins, either natural or synthetic
In 2022, Pierre Guériau used the X-rays from the PUMA beamline at the synchrotron SOLEIL to create microtomography images of these tiny, millimeter-sized flies frozen in resin. These are high-resolution, 3D reconstructions obtained by the equivalent of 7,500 X-rays for each sample, which rotates on its axis. This is enhanced by mathematical analysis that allows the reconstruction of cross-sections of the small animal.
Each insect is placed in different conditions of resin encapsulation and exposure to temperature cycles. These temperature variations, ranging from 150 to 250°C, at different speeds, are one of the few available methods to simulate an insect's journey through geological ages and upheavals.
Paleontologists are well aware that this process is imperfect, which is why Pierre Guériau is meticulously working to refine and perfect it. Specific resins, combined with specific temperature histories, produce different effects: some organs are better preserved than others.
To assess these levels of preservation, Pierre takes an original approach. He "enters the pixel" of his black-and-white microtomography images to analyze the density of the gray shades. "We presented our results at conferences, and the research community working on amber was enthusiastic and very curious. No one had ever observed before that a change in temperature could modify the density of the fly's eye."
The methodology used to characterize fossils is what's at stake here. And this variable density observed in the images—where does it come from? Is it due to more compressed material, or is it a chemical change in the organ itself?
This question opens up a second avenue of research. To "attack" the organic matter, there's nothing better than infrared, which interacts well with tissues. So it's infrared spectroscopy that allows Pierre to distinguish between cases where the material is compressed and those where it has been chemically altered. Again, in this work, the methodology itself is being refined and clarified.
While the first publication based on the images taken on PUMA is in preparation, Pierre Guériau doesn't rule out continuing his infrared investigation with the synchrotron, particularly using the SMIS beamline, which would be especially suited. "Life always finds a way—and so does the passionate paleontologist," he concludes with a smile, paraphrasing Jurassic Park.