Scientists looking at some of the first rocks to be dated have decided that rocks which had taken “10 million years” to form — instead found under study that “most of the formations originated during the Ireviken event, which lasted for only 1 million years or so.”
Really, that replaces about 10 megayears with “only 1 million years or so”, and since many, many other rocks are dated based on these ages, it looks like much other rock is about to lose 9 million or so years.
What surprises me is that they’re basing these dates on “the ratio between two isotopes of carbon, carbon-13 and carbon-12, in a rock sample,” but carbon isotopes decay fairly fast — maybe 100 kiloyears tops — so I wonder about this being used on rock which is aged at hundreds of millions of years old. Well, perhaps that’s another thing that will be re-considered while they’re analysing everything.
It’s going to be interestig to see what various implications arise (what ideas change) as rocks with formally “certain” dates gradually get new birthdays. Will formations change as a unit, or will parts “move” relative to the rest? What events are going to swap places? What pet theories will have to find new homes?
Comments
C-12 and C-13 are both regarded as "stable" (not radioactive); their half-life in the billions of years.
All of which stikes me as a much more serious problem for psuedo scientists who want to prove that the earth is 10k years old than for real goeologists.
2% difference: the correction is across the absolute rate of formation, not across the rocks’ entire lifespan. That’s why there is a fuss in the first place — much other rock dated using the same process is going to need editing. One of the risks of basing everything on one’s optimistic first guess, probably.
The dudes wanting 10ka — AFAICT — are down on the whole set of assumptions underlying this method of dating, rather than the “mere” 5- to 10-fold change in elapsed time which is distressing more-conventional geologists.
If they measured the rate directly then this is indeed a big change but if they just measured start and end times then I stick by my conclusion that this only constitutes a 2% error on one end (both start and end times presumably being measured as years BP).