Paleontology dating fossils
However, abiotic mechanisms for stromatolitic growth are also known, leading to a decades-long and sometimes-contentious scientific debate regarding biogenesis of certain formations, especially those from the lower to middle Archaean eon.
It is more widely accepted that stromatolites from the late Archaean and through the middle Proterozoic eon were mostly formed by massive colonies of cyanobacteria (formerly known as blue-green "algae"), and that the oxygen byproduct of their photosynthetic metabolism first resulted in earth’s massive banded iron formations and subsequently oxygenated earth’s atmosphere.
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.
While most fossils are several thousands to several billions of years old, there is no minimum age for a fossil.
Fossils vary in size from microscopic, such as single cells, to gigantic, such as dinosaurs.
C-14 is another radioactive isotope that decays to C-12. Because of its short half-life, the number of C-14 isotopes in a sample is negligible after about 50,000 years, making it impossible to use for dating older samples. in Earth-Space Science from West Chester University of Pennsylvania.
C-14 is used often in dating artifacts from humans. Fiore taught high school science for 7 years and offered several teacher workshops to regarding education techniques.
These samples are carefully cataloged and analyzed with a mass spectrometer.These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying decomposition.Lagerstätten span geological time from the Cambrian period to the present.Corina Fiore is a writer and photographer living in suburban Philadelphia. She worked as a staff writer for science texts and has been published in Praxis review materials for beginning teachers.Fossils (from Latin fossus, literally "having been dug up") are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms.