Present status of the lead method of age determination

Technical Report · Sat Aug 01 04:00:00 EDT 1953

DOI:https://doi.org/10.2172/4368445· OSTI ID:4368445

Kulp, J. Laurence; Bate, George L.; Broecker, Wallace S.

The available results on the age of radioactive minerals as determined by the various isotopic ratios Pb²⁰⁶/U²³⁸, Pb²⁰⁷/U²³⁵, Pb²⁰⁷/Pb²⁰⁶, Pb²⁰⁶/Pb²¹⁰ and Pb²⁰⁸/Pb²³² are summarized. The probable sources of error are each evaluated for the range of conditions expected for these minerals. Nomographs are presented which simplify the calculation of the age of a mineral from the isotopic ratio. It is concluded that the 207/235 and 206/210 ages are the most reliable over the greater range of geologic time. The 206/238 age is generally correct to 5-10% and supersedes the 207/235 age in accuracy for young minerals. The Pb²⁰⁸/Th²³², age is considered useable for minerals high in thorium content. The 207/206 age is the least reliable of all.

• Research Organization: Columbia Univ., Palisades, NY (United States). Lamont Geological Observatory
• Sponsoring Organization: US Atomic Energy Commission (AEC)
• NSA Number: NSA-07-004120
• OSTI ID: 4368445
• Report Number(s): NYO--6200
• Country of Publication: United States
• Language: English

Related Subjects

AGE ESTIMATION
ERRORS
GEOLOGY
LEAD 206
LEAD 207
LEAD 208
LEAD 210
MINERALOGY, METALLURGY, AND CERAMICS
MINERALS
NUMERICALS
THORIUM 232
URANIUM 235