Advanced sulfur isotope calculator for fieldwork and laboratories. Convert ratios and deltas with ease instantly. Explore mixing and fractionation using transparent exports and notes.
| Sample | R_sample (³⁴S/³²S) | R_std | Calculated δ³⁴S (‰) |
|---|---|---|---|
| Gypsum A | 0.0445200 | 0.0441626 | +8.09 |
| Pyrite B | 0.0439500 | 0.0441626 | −4.81 |
| Seawater Sulfate | 0.0450100 | 0.0441626 | +19.18 |
Values are illustrative for demonstrating calculations and formatting.
Delta notation
δ³⁴S (‰) = ((R_sample / R_std) − 1) × 1000
Back-conversion
R_sample = R_std × (δ³⁴S/1000 + 1)
Fractionation (small approximation)
α = R_A / R_B, then ε ≈ (α − 1) × 1000
Mixing is shown using both a linear δ approximation and a ratio-exact method, because isotope mixing is fundamentally linear in ratio space.
Sulfur isotope results are commonly expressed as δ³⁴S in per mil relative to a reference material. The calculator uses a reference ratio (R_std) to convert measured ³⁴S/³²S ratios into δ values. Keeping R_std consistent across projects prevents artificial offsets when comparing sulfate, sulfide, and elemental sulfur datasets from different laboratories.
When you enter a measured ratio, δ³⁴S is computed from the relative deviation of R_sample from R_std and scaled by 1000. The reverse conversion is equally useful when modeling or when a publication requires ratios. Both directions help reconcile instrument outputs, data archives, and geochemical models that may store results in different formats.
Fractionation is summarized with the fractionation factor α = R_A/R_B and the small-approximation enrichment ε ≈ (α − 1) × 1000. This is convenient for interpreting biological sulfate reduction, sulfide oxidation, or mineral precipitation where one phase is systematically heavier or lighter. Report which phases define A and B, and keep sign conventions explicit.
Two-endmember mixing is often discussed in δ space, but strict mass balance is linear in isotope ratios. The calculator therefore shows a ratio-exact mixing outcome by converting δ endmembers to ratios, mixing by fraction, then converting back to δ. The linear δ mix is also shown as a quick approximation, highlighting where curvature can emerge at larger contrasts.
For dependable results, check that ratios are positive and that fractions range from 0 to 1. Choose an appropriate rounding level and preserve raw measurements for traceability. In reporting, include the reference standard, the measurement method, any corrections, and the final δ³⁴S values with uncertainty so readers can compare across studies and time.
Data reviewers often check consistency across standards and replicates. Use one R_std for every conversion and document any drift corrections. For duplicate runs, compute δ³⁴S for each measurement and compare the spread with expected precision. Large deviations can signal carryover, peak interference, or preparation issues. For modeling, keep ratios at full precision and round δ only for display. When comparing sites, report mean, median, and range, and state the phase and redox context. Export results for traceable records. Include uncertainty when available, since small differences can be meaningful in interpretation decisions. too.
It expresses the relative difference between a sample’s ³⁴S/³²S ratio and the chosen reference ratio, scaled by 1000. Positive values are enriched in ³⁴S relative to the reference.
Use the ratio that matches your reporting standard and laboratory calibration. Keep it consistent across a dataset to avoid introducing offsets when comparing samples or combining studies.
Isotope mass balance is linear in ratios, not in δ. Converting δ endmembers to ratios, mixing by fraction, then converting back avoids bias when endmembers differ strongly.
α is the ratio of isotope ratios between two phases. ε is an approximate per mil enrichment derived from α. State which phase is A and which is B so the sign has clear meaning.
Use enough decimals to reflect analytical precision without overstating certainty. Keep unrounded values for calculations and archives, then round δ or ε values for tables and figures.
Yes. Use the CSV export for spreadsheets and the PDF export for lab notes or reports. Exports include the selected mode, inputs, and computed outputs for traceability.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.