Carbon dating in massachusetts
Young Earthers point to an infamous dating error as evidence that the Earth is only as old as the Bible says.by Brian Dunning Filed under General Science, Natural History, Religion Skeptoid Podcast #146 March 24, 2009 Podcast transcript Today we're going to point our skeptical eye at one of the key players in the debate between geologists and Young Earthers over the age of the Earth. Steven Austin took a sample of dacite from the new lava dome inside Mount St. The dacite sample was known to have been formed from a 1986 magma flow, and so its actual age was an established fact. Austin submitted the sample for radiometric dating to an independent laboratory in Cambridge, Massachusetts.Of most people who have heard of this incident before, that's probably about the total depth of what they've heard.And there's pretty good reason for this: Geology dating is pretty complicated, and if you look at Dr.Austin, Geocron Laboratories, was of a type sensitive enough to only detect higher concentrations of argon gas.Geocron clearly stated that their equipment was only capable of accurate results when the sample contained a concentration of argon high enough to be consistent with 2,000,000 years or older.If I take a sample and measure an argon to potassium ratio of 0, I know that this sample is 2.4 billion years old.
The first has to do with the reason Geocron's equipment was considered useful only for high concentrations of argon.
But for a sample with little or no argon, it would produce a falsely old result. The papers all go into great detail describing the various ways that argon-containing compounds can be incorporated into magma.
These include the occlusion of xenoliths and xenocrysts, which are basically contaminants from existing old rocks that get mixed in with the magma; and phenocrysts, which are crystals of all sorts of different minerals that form inside the rock in different ways depending on how quickly the magma cools. Austin claims that xenoliths and xenocrysts were completely removed from the samples before testing, and that the wrong results are due to phenocrysts, which form to varying degrees in all magma, and thus effectively cast doubt on all potassium-argon testing done throughout the world.
Obviously both sides of this debate have agendas to promote, and that means that any summary you're likely to read was probably motivated by one agenda or the other.
Let's begin with a basic understanding of the radiometric dating technique used, K-Ar, or potassium-argon.
There would always be a certain amount of argon inside the mass spectrometer left over from previous experiments.