Lab-made fossils cram 1000s of years into 24 hours
Fossils are certainly fascinating, but the darn things do take rather a long time to form. What if you want to fossilize something as fast as possible? Well, scientists have developed a method of doing so within about 24 hours – and it could lead to big advances in the field of paleontology.
There are different ways in which fossils can form naturally, although the process typically begins when bones (or other biological material) get buried underground – this often occurs as sediments accumulate over top of them. Over the course of anywhere from tens of thousands to millions of years, the buried bones are subjected to heat and pressure. Without going into too much detail, this causes the chemicals that they're composed of to be replaced with minerals, turning the bones to stone.
In an effort to better understand how the fossilization process affects various types of biological materials, scientists at Britain's University of Bristol developed a lab-based process in which fresh specimens such as bird feathers, lizard limbs, and leaves can be converted into "synthetic" fossils within approximately one day.
Using a hydraulic press, the items are first packed into clay tablets about the diameter of a dime. Each tablet is then placed in a sealed metal tube, which gets heated to over 410 ºF (210 ºC) while also being subjected to 3,500 psi (241 bar) of pressure. After around 24 hours of this treatment, the tablets are cracked open to reveal their now-fossilized contents.
To the naked eye, the synthetic fossils reportedly look just like ones made naturally. Even when they were examined using a scanning electron microscope, the similarities continued.
"We could see exposed melanosomes, the structures that contain the biomolecule melanin that give feathers and skin their color, and scientists have found melanosomes in real fossils too," says Field Museum post-doctoral researcher Evan Saitta, who worked on the project when he was a U Bristol PhD student. "Less stable materials, like proteins and fatty tissues, don't show up in real fossils, and they weren't present in ours either."
While there have been previous attempts at creating lab-produced fossils, they didn't allow the unstable biomolecules that naturally break down in the fossilization process to leak out as they normally would. As a result, the resulting synthetic fossils were surrounded by a "rancid-smelling goo" containing compounds that wouldn't be present in regular fossils. By contrast, the new process lets those breakdown products leach out into the clay, leaving a more natural fossil behind.
"The fossil record yields data that can be hard to interpret. For us to answer our questions, we need to understand how fossils form," says Saitta. "Our experimental method is like a cheat sheet. If we use this to find out what kinds of biomolecules can withstand the pressure and heat of fossilization, then we know what to look for in real fossils."
The research, which was supervised by Dr. Jakob Vinther, is described in a paper that was recently published in the journal Paleontology.