World's Oldest Rock?

A zircon is ZrSiO4, it is also the group name for tetragonal minerals with the general formula ASiO4 where "A" can only be Zr, Hg, Th, or U.Pb will not fit in this crystal structure. Suppose our little zircon has lead in it, where do you suppose it came from?

FEY, Do you work for Sunburst? If you do I know you. Would have sent you a PM but it's a PIA on this site.

FEY, I don't post here much, but I do read nearly everything. You seem like a nice kid. You need a geology job, maybe I can help you out.Let's get you in the network, on facebook I'm Martin Granica on Linkedin I'm Martin P. Granica.I know more people than you can imagine in the oil and gas industry. Sometimes they are looking for a bright kid, for the summer or maybe more.BTW I don't care if people know my name, I'm a Conservative Republican and armed, and my name and address are a matter of public record since Feb. of 1963 when I got my first Amateur Radio Callsign WB2RJR from the FCC.For Admin: Who cares if this is off topic, I don't.

I didn't realize that this was just a useless NPR article about some work T. Mark Harrison did back in 2001. (My tax dollars at work.)You can read about Mark Harrison here and down in paragraph 6 about this work on zircons.Geological Society of America - Honors & AwardsThere is however a little problem with these zircons not being the closed system Mr. Harrison thought they were back in 2001. You can read about it in this GSA abstract from 2011 here.Metamorphic replacement of mineral inclusions in detrital zircon from Jack Hills, Australia: Implications for the Hadean Earth | Geology | GeoScienceWorldIf that went over your head it's explained a bit clearer here:WordPress.comSo basically like most stuff on NPR the article in the OP is mostly bullshit.P.S. in my last link at the bottom you might like reading the first link there.Earthfs eTime Capsulesf May Be Flawed (Edited by petrophysics1, : Add PSEdited by petrophysics1, : No reason given.