tag:blogger.com,1999:blog-12320946.post116181738980252913..comments2024-01-24T08:28:13.011+08:00Comments on Plantagenet Penguinista: Blind dates?Leon RJ Brookshttp://www.blogger.com/profile/01425209164513409690noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-12320946.post-1162176434653133442006-10-30T10:47:00.000+08:002006-10-30T10:47:00.000+08:00Do you have some reason to believe that they measu...Do you have some reason to believe that they measured the rate of formation directly as opposed to measuring the start and end times. The press release you linked is vague on this and the work does not appear to have made it into the formal literature yet.<BR/><BR/>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).Majorhttps://www.blogger.com/profile/08202634243313936534noreply@blogger.comtag:blogger.com,1999:blog-12320946.post-1162075409087509632006-10-29T06:43:00.000+08:002006-10-29T06:43:00.000+08:00C-12/C-13: yup, sorry, ’tis C-14 which vanishes so...C-12/C-13: yup, sorry, ’tis C-14 which vanishes so fast, so a C-14 date for any of this would be nonsense but the stabler isotopes make a better argument.<BR/><BR/>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.<BR/><BR/>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.Leon RJ Brookshttps://www.blogger.com/profile/01425209164513409690noreply@blogger.comtag:blogger.com,1999:blog-12320946.post-1161919200511144492006-10-27T11:20:00.000+08:002006-10-27T11:20:00.000+08:00This "9 million year difference" needs to be put i...This "9 million year difference" needs to be put into context. The calculated age of the bottom if the formation has not changed. The age of the top of the formation has been re-calulated at 418 million years rather than 426 million years; a correction of roughly 2%.<BR/><BR/>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.Majorhttps://www.blogger.com/profile/08202634243313936534noreply@blogger.comtag:blogger.com,1999:blog-12320946.post-1161851620817902802006-10-26T16:33:00.000+08:002006-10-26T16:33:00.000+08:00some carbon isotopes decay fast.C-12 and C-13 are ...<B><I>some</I></B> carbon isotopes decay fast.<BR/><BR/>C-12 and C-13 are both regarded as "stable" (not radioactive); their half-life in the billions of years.Majorhttps://www.blogger.com/profile/08202634243313936534noreply@blogger.com