Lead Isotope Triple Plot
Definition
A graphical display of 207Pb/204Pb against 206Pb/204Pb and 208Pb/204Pb against 206Pb/204Pb. Different ore deposits fall in distinct clusters on these plots, and an unknown sample can be attributed to a source region by where it plots relative to the reference data.
- Axes
- 207Pb/204Pb, 208Pb/204Pb vs 206Pb/204Pb
- Output
- Two paired scatter plots
- Interpretation
- Ore deposits form distinct clusters
- Use
- Attribute unknown sample to source region
Common questions
Why plot two ratio pairs instead of comparing a single ratio?+
A single isotope ratio can occasionally overlap between unrelated ore deposits by coincidence. Requiring an unknown sample to fall within a cluster on both plots simultaneously reduces the chance of a false regional match.
What limits the reliability of a triple plot attribution?+
It depends on having a well-populated reference database of known ore deposits; a source region absent from the reference data cannot be correctly identified, and mixed-source materials can plot between clusters rather than clearly within one.
Related terms
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- Strontium Isoscape
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