Varve Layer Chronology Counter
Count varve years on nonoverlapping sections with explicit missing/duplicate annual-layer assumptions and a supplied calendar boundary; laminae are not automatically annual.
Description
Varves are sediment layers interpreted as annual deposits.
Varves are sediment layers interpreted as annual deposits. Missing annual layers and duplicate subannual laminae require explicit corrections.
Count varve years on nonoverlapping sections with explicit missing/duplicate annual-layer assumptions and a supplied calendar boundary; laminae are not automatically annual.
When to use Varve Layer Chronology Counter
Use this tool to count varve years on nonoverlapping sections with explicit missing/duplicate annual-layer assumptions and a supplied calendar boundary; laminae are not automatically annual.
Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
How to use Varve Layer Chronology Counter and understand its results
- Prepare the fossil measurements or occurrence records and the chosen calibration parameters. Retain the stated coordinate, age and measurement conventions.
- Enter observedLayersPerSection, estimatedMissingAnnualLayers, estimatedDuplicateSubannualLayers, oldestBoundaryCalendarYear using the field table and calculation rules, then run the tool.
- Read correctedYearsPerSection, representedChronologyYears, youngestBoundaryCalendarYear. 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 |
|---|---|---|---|
| observedLayersPerSection | Observed layers per section | list of number | Required |
| estimatedMissingAnnualLayers | Estimated missing annual layers | list of number | Required |
| estimatedDuplicateSubannualLayers | Estimated duplicate subannual layers | list of number | Required |
| oldestBoundaryCalendarYear | Oldest boundary calendar year | number | Required |
Align nonnegative integer section counts and corrections. Require nonnegative corrected counts, sum nonoverlapping sections and add the represented years to the supplied oldest calendar boundary.1
Paired lists must be nonempty and have equal lengths.
corrected years = observed + missing − duplicate layers Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| correctedYearsPerSection | Corrected years per section | list of number |
| representedChronologyYears | Represented chronology years | number |
| youngestBoundaryCalendarYear | Youngest boundary calendar year | number |
{
"input": {
"observedLayersPerSection": [
10,
20
],
"estimatedMissingAnnualLayers": [
1,
2
],
"estimatedDuplicateSubannualLayers": [
0,
3
],
"oldestBoundaryCalendarYear": 1900
},
"output": {
"correctedYearsPerSection": [
11,
19
],
"representedChronologyYears": 30,
"youngestBoundaryCalendarYear": 1930
}
}Limitations and assumptions
Annual periodicity and boundary dating must already be established; laminae are not automatically years.
Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Growth Ring Lines of Arrested Growth Counter: Combine observed LAG counts with explicit resorption/double-band assumptions, taking the largest section-based minimum annual-age scenario; annual periodicity is an assumption, not automatically established skeletal age. For a complementary task, use Stratigraphic Range Extent: Summarize observed section-position span and endpoint measurement uncertainty, not true taxon duration; positions share a caller increasing chronological/section convention.
References
-
Varve Layer Chronology Counter — tool.io
Similar or alternative tools
- Growth Ring Lines of Arrested Growth Counter
Combine observed LAG counts with explicit resorption/double-band assumptions, taking the largest section-based minimum annual-age scenario; annual periodicity is an assumption, not automatically established skeletal age.
- Stratigraphic Range Extent
Summarize observed section-position span and endpoint measurement uncertainty, not true taxon duration; positions share a caller increasing chronological/section convention.