Cesium 137 Peak Year Marker Lookup

Locate actual unique core Cs137 activity maximum and annotate explicit externally justified marker year; not universally assigning 1963/1986, hemispheric fallout timing or asserting unmixed sediment chronology.

Description

A measured Cs-137 peak can mark a core depth only when it is uniquely resolved.

A measured Cs-137 peak can mark a core depth only when it is uniquely resolved. The calendar assignment needs independent justification.^[1]

Enter at least two nonnegative strictly increasing depths, aligned nonnegative activities and integer assigned year 1900–2199. Reject absent/tied maxima; return peak depth and supplied year.

When to use Cesium 137 Peak Year Marker Lookup

Use Cesium 137 Peak Year Marker Lookup when you need to evaluate the supplied records under the calculation and evidence rules below. No universal1963/1986 date, hemisphere fallout history or unmixed chronology is assumed.

Prepare the observed lake or sample measurements and explicit calibration, reference values or thresholds requested. Keep depth coverage, units, dates and sampling conditions consistent.

How to use Cesium 137 Peak Year Marker Lookup and understand its results

Prepare the observed lake or sample measurements and explicit calibration, reference values or thresholds requested. Keep depth coverage, units, dates and sampling conditions consistent.
Enter coreDepthsCm, measuredCs137Activities, callerAssignedMarkerYear using the field table and calculation rules, then run the tool.
Read uniqueObservedPeakDepthCm, callerAssignedPeakYear. 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
coreDepthsCm	Core depths cm	list of number	Required
measuredCs137Activities	Measured cs137 activities	list of number	Required
callerAssignedMarkerYear	Caller assigned marker year	number	Required

Enter at least two nonnegative strictly increasing depths, aligned nonnegative activities and integer assigned year 1900–2199. Reject absent/tied maxima; return peak depth and supplied year.

index=unique positive activity maximum; markerDepth=depth[index]

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
uniqueObservedPeakDepthCm	Unique observed peak depth cm	number
callerAssignedPeakYear	Caller assigned peak year	number

json

{
  "input": {
    "coreDepthsCm": [
      0,
      1,
      2
    ],
    "measuredCs137Activities": [
      1,
      5,
      2
    ],
    "callerAssignedMarkerYear": 1963
  },
  "output": {
    "uniqueObservedPeakDepthCm": 1,
    "callerAssignedPeakYear": 1963
  }
}

Limitations and assumptions

No universal1963/1986 date, hemisphere fallout history or unmixed chronology is assumed.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Sediment Accumulation Rate MM Year Calculator: Two independently dated sediment markers define an interval-average thickness accumulation rate. This does not establish a continuous deposition history. For a complementary task, use Sediment Focusing Factor Calculator: Core radionuclide inventory may differ from an independently justified atmospheric reference. Their ratio is an apparent focusing measure.

References

Cesium 137 Peak Year Marker Lookup — tool.io

Similar or alternative tools

Sediment Accumulation Rate MM Year Calculator
Two independently dated sediment markers define an interval-average thickness accumulation rate. This does not establish a continuous deposition history.
Sediment Focusing Factor Calculator
Core radionuclide inventory may differ from an independently justified atmospheric reference. Their ratio is an apparent focusing measure.