Stromatolites dating method
Within three weeks, there will be nothing left but a few small bones." A fossil normally preserves only a portion of an organism, usually that portion that was partially mineralized during life, such as bones and teeth.Trace fossils are the marks left by a living organism, such as feces, footprints or impressions of feathers or leaves.Together with oncoids (formerly called "algal biscuits" or "Girvanella"), they typically form by the baffling, trapping, and precipitation of particles by communities of microorganisms such as bacteria and algae.In some cases, they can form inorganically, when seawaters are oversaturated with chemical precipitates.This may be somewhat surprising, since the oldest rocks are only a little older: 3.8 billion years old!Cyanobacteria are among the easiest microfossils to recognize.We humans have descended from organisms that adapted to living in a prokaryotic world, and we humans retain (conserved in evolutionary terms) in our mitochondria the cellular machinery to power our cells that we inherited (i.e., endosymbiosis) from the prokaryotes of deep time on earth.Stromatolites and their close cousins the thrombolites, are rock-like buildups of microbial mats that form in limestone- or dolostone-forming environments.
Paleontologists consider materials younger than 10,000 years ago “recent”.They maintain and recycle the atomic ingredients of which proteins, the essence of life, are made, including oxygen, nitrogen and carbon.We humans have descended from organisms that adapted to living in a prokaryotic world, and we humans retain (conserved in evolutionary terms) in our Eukaraotic mitochondria the cellular machinery to power our cells that we inherited (i.e., Endosymbiosis) from the prokaryotes of deep time on earth.This definition is, in fact, such a gross oversimplification as be scientifically useless.
The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3.5 billion years old.
The oldest uncontested fossils on earth are 2 billion year-old stromatolites in Minnesota, Wisconsin, and Ontario.