Paleontology dating fossils
The totality of fossils and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record.The study of fossils across geological time, how they were formed, and the evolutionary relationships between taxa (phylogeny) are some of the most important functions of the science of paleontology.Confirmation of the Warrawoona microstructures as cyanobacteria would profoundly impact our understanding of when and how early life diversified, pushing important evolutionary milestones further back in time (reference).The continued study of these oldest fossils is paramount to calibrate complementary molecular phylogenetics models.Half-life is the amount of time it takes for half of the parent isotopes to decay. In another 5,730 years, the organism will lose another half of the remaining C-14 isotopes.This process continues over time, with the organism losing half of the remaining C-14 isotopes each 5,730 years.
There are several common radioactive isotopes that are used for dating rocks, artifacts and fossils. U-235 is found in many igneous rocks, soil and sediment.
Earth’s oldest fossils are the stromatolites consisting of rock built from layer upon layer of sediment and precipitants.
Based on studies of now-rare (but living) stromatolites (specifically, certain blue-green bacteria), the growth of fossil stromatolitic structures was biogenetically mediated by mats of microorganisms through their entrapment of sediments.
Many rocks and organisms contain radioactive isotopes, such as U-235 and C-14.
These radioactive isotopes are unstable, decaying over time at a predictable rate.