Strontium Isoscape
Definition
A map of 87Sr/86Sr values across a defined geographic area, built from measurements of soil, plants, or water. Used to compare the ratio of an unknown sample against a spatial database to identify the most probable origin region.
- Output
- Map of 87Sr/86Sr values by region
- Built from
- Soil, plant, and water samples
- Use
- Compares unknown sample against database
- Field
- Geoforensics
Common questions
How precise is an origin assignment made from an isoscape?+
Precision depends on how densely the underlying region has been sampled and how much its geology varies; well-mapped areas can narrow origin to a specific district, while sparsely sampled or geologically uniform regions only narrow it to a broad zone.
What limits the reliability of isoscape-based provenance?+
Different regions can share similar bedrock ages and therefore similar ratios, producing overlapping candidate areas, so isoscape results are normally reported as a probability surface across several possible regions rather than a single confirmed location.
Related terms
- 87Sr/86Sr Ratio
- 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...
- 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...