another sample is analyzed by a different geologist using different isotopes. he determines there is 75% Pb daughter product in the sample. he suspects some error and decides to reanalyze the sample. what led him to conclude there was a problem with his initial result?
2007-12-09 14:28:52 · 2 answers · asked by PublicSUD 2 in Science & Mathematics ➔ Earth Sciences & Geology
What U-Pb system are you using? U 238 or U 235?
U 238 has a half life of 4.5 billion years. U 235 has a half life of 713 million years.
If there's 75% of Pb 2 half lives have passed.
Define "greater than 1 million". Perhaps I am being daft, but this question seems to be vague.
2007-12-09 14:41:06 · answer #1 · answered by Lady Geologist 7 · 0⤊ 0⤋
Because the breakdown of Uranium into Lead takes a very long time, after only 1 million years, the amount of Uranium would have changed by such a small amount that it would be very difficult to measure properly.
The half-lives of Uranium are as follows:
235U: 703.8 million years
238U: 4468 million years
2007-12-09 22:50:16 · answer #2 · answered by Geologist Greg 5 · 0⤊ 0⤋