Carbon dating geology
He said that his team and the laboratories they employed took special care to avoid contamination.
That included protecting the samples, avoiding cracked areas in the bones, and meticulous pre-cleaning of the samples with chemicals to remove possible contaminants.
This is different to relative dating, which only puts geological events in time Most absolute dates for rocks are obtained with radiometric methods.
Radiocarbon dating measures radioactive isotopes in once-living organic material instead of rock, using the decay of carbon-14 to nitrogen-14.Knowing that small concentrations of collagen can attract contamination, they compared precision Accelerator Mass Spectrometry (AMS) tests of collagen and bioapatite (hard carbonate bone mineral) with conventional counting methods of large bone fragments from the same dinosaurs. Mary Schweitzer, associate professor of marine, earth, and atmospheric sciences at North Carolina State University, surprised scientists in 2005 when she reported finding soft tissue in dinosaur bones.These, together with many other remarkable concordances between samples from different fossils, geographic regions and stratigraphic positions make random contamination as origin of the C-14 unlikely". She started a firestorm of controversy in 20 when she reported that she had sequenced proteins in the dinosaur bone.The table below shows characteristics of some common radiometric dating methods.Geologists choose a dating method that suits the materials available in their rocks. Measuring isotopes is particularly useful for dating igneous and some metamorphic rock, but not sedimentary rock.
It's accuracy has been verified by using C-14 to date artifacts whose age is known historically.