87Sr/86Sr ratio
Definition
The ratio of radiogenic strontium-87 (produced by decay of rubidium-87) to the stable reference isotope strontium-86. Values range from roughly 0.703 in young ocean basalts to above 0.800 in ancient granites. This range encodes the bedrock age and Rb/Sr chemistry of the local geology.
Related terms
- Isoscape
- A map of isotope ratio variation across a geographic area, derived from systematic sampling of soil, water, plant, or mineral material; used...
- Lead isotope triple plot
- 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...
- Mixing model
- A mathematical framework for reconstructing the proportions of two or more isotopically distinct source materials in a mixture. Required whenever a forensic...
- Radiogenic ingrowth
- The progressive increase in a daughter isotope such as 87Sr over geological time as the parent nuclide (87Rb) decays. Materials with higher...
- Strontium isoscape
- A map of 87Sr/86Sr values across a defined geographic area, built from measurements of soil, plants, or water. Used to compare the...
Explained in
- Strontium and Lead Isotopes in GeoforensicsThe ratio of radiogenic strontium-87 (produced by decay of rubidium-87) to the stable reference isotope strontium-86. Values range from roughly 0.703 in young...