Hi Chris- "The C14 calibration data only goes back 24,000 years,"
Try 50,000 years - INCAL98. "and there have been no confirmed significant impacts during that time," Barringer? "and not even any well dated minor impacts. So how can spikes in the calibration curve be linked to impacts?" Actually, take a look at the INTCAL98 chart running back 50,000 YEARS. Note the spike and then the bump at 10,900 BCE. This is what is started driving Firestone - he saw a supernova at first, then a supernova injecting comets. "Even given a large impact (a big given)" Take a look at Barringer, and look at what has been found at Sheriden Cave, and by the way note the First Peoples' accounts of these multiple large comet fragment impacts at: http://forum.palanth.com/index.php/topic,1093.0.html I suppose the denial will go on for years, even after the AGU discussion/debates coming up soon. "there are plausible explanations for how this would affect C14 concentrations; far more plausible than the very unlikely production of neutrons." Yes, I know the releases energies are very high, and yes, there are multiple explanations, - sun, magnetosphere, supernova, etc. It will fall to those with more intelligence than I myself have left to sort it all out But plese note that the one spike that got to me was the spike roughly at the time of the Barringer Crater impact. Firestone is proposing multiple supenovas, from what is being sent around, but it sure looks to me like the energies in large hypervelocity impacts are indeed freeing neutrons. In the meantime, OSL dating for Odessa will be an open question for me. E.P. Grondine Man and Impact in the Americas (a pretty good book despite its flaws - write me off list for the meteorite list special.) PS - I have been wrong in the past, and reserve the right to be wrong both now and in the future. ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
