Scientists believe that soft tissue fossils, which are particularly rare on Earth, could hold clues to ancient life not only on our planet but also on other planets.
Researchers at Oxford University have published a study wherein they have revealed how mineralogy of the surrounding earth is key to conserving soft parts of organisms, and finding more exceptional fossils to garner greater understanding of ancient life on Earth and other planets. They have also said that their finding could have implications on the work being carried out by NASA Mars rover Curiosity by enabling it to speed up the search for traces of life on the Red Planet.
Researchers at the University carried out a study by examining more than 200 Cambrian rock samples and subjecting them to X-ray diffraction analysis to determine their mineralogical composition, comparing rocks with Burgess Shale-type fossils with those with only fossilised shells and bones.
They found that soft tissue fossils are generally found in rocks rich in the mineral berthierine, one of the main clay minerals identified by the previous study as being toxic to decay bacteria.This particular mineral is interesting because it forms in tropical settings when the sediments contain elevated concentrations of iron indicating that Burgess Shale-type fossils are likely confined to rocks which were formed at tropical latitudes and which come from locations or time periods that have enhanced iron.
The study provides a mineralogical signature which can be used to find the more elusive sites that are home to these extraordinary fossils.
“The mineralogical associations we identified mean that for a given Cambrian sedimentary mudrock we can predict with around 80% accuracy whether it is likely to contain Burgess Shale-type fossils,” explain scientists.
This means that if we are looking for life on other planets, we probably need to find fossils of entirely soft organisms, and Burgess Shale-type fossilisation provides a way. NASA’s Curiosity rover has the ability to record mineralogy on the Martian surface, so it could potentially look for the types of rocks which might be most conducive to preserving these fossils.