Amino Acid Racemization Age
Infer symmetric reversible amino-acid racemization age from D/L using caller effective rate and initial ratio; assumes a closed system/fixed kinetic history, not a generic biological age.
Description
A reversible racemization model transforms a measured D/L ratio into an age under a supplied effective rate.
A reversible racemization model transforms a measured D/L ratio into an age under a supplied effective rate. The initial ratio and kinetic history are part of that scenario.1
Infer symmetric reversible amino-acid racemization age from D/L using caller effective rate and initial ratio; assumes a closed system/fixed kinetic history, not a generic biological age.
When to use Amino Acid Racemization Age
Use this tool to infer symmetric reversible amino-acid racemization age from D/L using caller effective rate and initial ratio; assumes a closed system/fixed kinetic history, not a generic biological age.
Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.
How to use Amino Acid Racemization Age and understand its results
- Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.
- Enter measuredDRatio, initialDRatio, symmetricRacemizationRatePerYear using the field table and calculation rules, then run the tool.
- Read racemizationAgeScenarioYears. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| measuredDRatio | Measured d ratio | number | Required |
| initialDRatio | Initial d ratio | number | Required |
| symmetricRacemizationRatePerYear | Symmetric racemization rate per year | number | Required |
Enter a positive symmetric racemization rate per year and ratios satisfying 0≤initial≤measured<1. Use log1p(r)−log1p(−r) for the transform, subtract the initial transform and divide by twice the rate. Return years; equal ratios yield zero.
age = {ln[(1+r)/(1−r)]−ln[(1+r0)/(1−r0)]}/(2 rate) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| racemizationAgeScenarioYears | Racemization age scenario years | number |
{
"input": {
"measuredDRatio": 0.5,
"initialDRatio": 0,
"symmetricRacemizationRatePerYear": 0.01
},
"output": {
"racemizationAgeScenarioYears": 54.930614433405474
}
}Limitations and assumptions
Closed-system symmetric kinetics and a fixed effective rate are assumed. Thermal history, composition and open-system changes are not fitted, and this is not a generic biological age.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Obsidian Hydration Rind Age: Evaluate a caller calibrated squared-rind hydration age subtracting inherited squared growth, not rind width linearly; effective hydration rate is environment/composition-specific. For a complementary task, use OSL Age: Infer residual-corrected OSL age with independent dose/rate uncertainties, retaining signed residual nondetections; assumes full resetting and constant effective dose rate, not a validated burial age.
References
-
Amino Acid Racemization Age — tool.io
Similar or alternative tools
- Obsidian Hydration Rind Age
Evaluate a caller calibrated squared-rind hydration age subtracting inherited squared growth, not rind width linearly; effective hydration rate is environment/composition-specific.
- OSL Age
Infer residual-corrected OSL age with independent dose/rate uncertainties, retaining signed residual nondetections; assumes full resetting and constant effective dose rate, not a validated burial age.