Paleontology dating fossils
Fossils may also consist of the marks left behind by the organism while it was alive, such as the footprint or feces of a reptile.These types of fossil are called trace fossils (or ichnofossils) as opposed to body fossils.
Due to its long half-life, U-235 is the best isotope for radioactive dating, particularly of older fossils and rocks. The half-life of C-14, however, is only 5,730 years.By comparing this ratio to the half-life logarithmic scale of the parent isotope, they are able to find the age of the rock or fossil in question.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.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.