1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Common lead vs radiogenic lead

  1. Dec 1, 2013 #1
    1. The problem statement, all variables and given/known data

    Learning about lead-lead dating to determine the age of things (specifically the solar system using meteorites)... I can't seem to understand what the meaning of "common lead" is. So far the best I'm getting is that it is some sort of contaminant.

    What is the relationship/difference between the common lead, radiogenic lead that was formed from decay, and initial lead abundances. Is it the same as an initial lead abundance? I'm confused.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Dec 1, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    There are several stable isotopes of lead, only one of which is not formed as the result of the radioactive decay of heavier elements. Lead isotopes which result from radioactive decay are called 'radiogenic'. Lead-lead dating uses the ratio of the amount of 'radiogenic' lead to the amount of 'non-radiogenic' lead to estimate age.

    See: http://en.wikipedia.org/wiki/Lead-lead_dating
  4. Dec 1, 2013 #3
    yes but in my equations we have COMMON 207, 206, and 204 Pb compared with radiogenic 207 and 206Pb and non-radiogenic 204Pb. So what is common lead? My reference states "common, the lead that was present in the sample at the time of its crystallization and the lead introduced by terrestrial contamination."

    So is common lead just the abundance of initial lead combined with contamination lead? Hmm.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted