Rhenium osmium dating
Knowing precisely how old the fossil is also allowed the researchers to estimate that the very first plant likely evolved around 1.25 billion years ago.Bangiomorpha, a microscopic fossil organism just fractions of a millimetre long, was first discovered beautifully preserved in layers of chert — effectively, glass — in cliffs on Somerset Island in Nunavut.It was described by British scientist Nick Butterfield in 1990.He named it: The fossil was extraordinary because it was found in a rock formation up to 1.2 billion years old and appeared to be the oldest multicellular organism that was a recognizable eukaryote — the group of complex organisms that include plants, animals and fungi — rather than a colony of microbes living together.
"Most recognizable eukaryotes don't show up until around 800 million years ago." The reason it was so hard to tell how old Bangiomorpha was is that to measure the age of rocks, geologists typically rely on chemical techniques that can only be applied to layers of volcanic rock, Gibson said, and there wasn't much of that in the cliffs where the fossils were found.
A Canadian-led study aims to settle the controversy over extraordinary Arctic fossils that represent the oldest known sexually reproducing organism and the oldest multicellular organism that used photosynthesis.
The fossil organism identified as a red algae called But the fact that its age could have been anywhere in a 500-million year span led to some controversy.
They camped on the tundra in lightweight tents at the tops of sea cliffs to avoid polar bears, then scrambled down to collect samples with simple rock hammers.
Once back at the lab, the researchers measured the amount of radioactive rhenium-187, a rare radioactive isotope found in seawater that accumulates in organic matter and decays to osmium-187.