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mLine 183:
Line 183: − +
→Zircon Dating
::::The sample taken for measurement was taken form an area of the crystal that was free of cracks. Let me make sure we're both clear on this: the total minimum age of the crystals was determined using <sup>207</sup>Pb/<sup>206</sup>Pb dating. The U/Pb dating I was talking about earlier was from another project published in ''Nature''. You're saying that because the two isotopes of the lead existed in different ratios over time, one isotope may have leached out (meaning more of one isotope left the crystal) at one time.
::::The sample taken for measurement was taken form an area of the crystal that was free of cracks. Let me make sure we're both clear on this: the total minimum age of the crystals was determined using <sup>207</sup>Pb/<sup>206</sup>Pb dating. The U/Pb dating I was talking about earlier was from another project published in ''Nature''. You're saying that because the two isotopes of the lead existed in different ratios over time, one isotope may have leached out (meaning more of one isotope left the crystal) at one time.
::::Even if the lead was somehow leaving the crystals (and there is no evidence that it is), there is no natural process which removes <sup>207</sup>Pb at a faster rate than the <sup>206</sup>Pb. Even if a lead-removing process started recently, it would still remove the two isotopes at the same rate leaving the ratio unchanged. Also, if the lead-removing process started and ended a long time ago, it would also remove the two isotopes at teh same rate leaving the ratio unchanged.--[[User:MichaelK|MichaelK]] 21:01, 15 May 2008 (EDT)
::::Even if the lead was somehow leaving the crystals (and there is no evidence that it is), there is no natural process which removes <sup>207</sup>Pb at a faster rate than the <sup>206</sup>Pb. Even if a lead-removing process started recently, it would still remove the two isotopes at the same rate leaving the ratio unchanged. Also, if the lead-removing process started and ended a long time ago, it would also remove the two isotopes at the same rate leaving the ratio unchanged.--[[User:MichaelK|MichaelK]] 21:01, 15 May 2008 (EDT)