Archaeomagnetic Date Lookup

Sampled archaeomagnetic direction compatibility against independently site/frame/edition-calibrated vectors; retains multi matches, not extrapolated dates, direction sign reversal or continuous age interval. Caller independently establishes sample/context/calibration applicability; not definitive chronology, provenance, taxonomy, disease or human identity.

Description

Archaeomagnetic matching compares directions under a common frame and dated reference.

Archaeomagnetic matching compares directions under a common frame and dated reference.^[1]

Sampled compatible dates can be multiple and are distinct from a continuous calibrated age interval. Use Archaeomagnetic Date Lookup to evaluate the supplied inputs under the model explained below.

When to use Archaeomagnetic Date Lookup

Use Archaeomagnetic Date Lookup to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.

How to use Archaeomagnetic Date Lookup and understand its results

Establish the units, measurement scope and model assumptions before entering values.
Enter Observed direction unit vector, Caller calibrated dates years, Caller calibrated direction vectors, Caller angular tolerance degrees using the field table and validation rules below, then run the tool.
Read Compatible caller sampled dates years, Sample angular differences degrees; interpret the units, signs, ordering and unknown-value placeholders described below.
Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.

Input field	Meaning	Value type	Requirement
observedDirectionUnitVector	Observed direction unit vector	array of number	Required; constraints below
callerCalibratedDatesYears	Caller calibrated dates years	array of number	Required; constraints below
callerCalibratedDirectionVectors	Caller calibrated direction vectors	array of array	Required; constraints below
callerAngularToleranceDegrees	Caller angular tolerance degrees	number	Required; constraints below

Enter a finite nonzero three-component observed direction, nonempty aligned sampled dates and nonzero three-component reference directions in one frame, and nonnegative tolerance in degrees. Normalize both vectors, clamp dot products to [−1,1], convert acos to degrees and select differences≤tolerance. Return all sampled angular differences and compatible dates in caller order. Dates need not be ordered or unique; tolerance is not capped at 180. No curve interpolation, installed regional history or age distribution occurs.

angle[i]=acos(clamp(dot(unitObserved,unitReference[i]),−1,1)); compatibleDates=angle≤callerTolerance

Use the field order, units and branch conditions described above.

Output field	Meaning	Value type
compatibleCallerSampledDatesYears	Compatible caller sampled dates years	array of number
sampleAngularDifferencesDegrees	Sample angular differences degrees	array of number

json

{
  "input": {
    "observedDirectionUnitVector": [
      1,
      0,
      0
    ],
    "callerCalibratedDatesYears": [
      100,
      200
    ],
    "callerCalibratedDirectionVectors": [
      [
        1,
        0,
        0
      ],
      [
        0,
        1,
        0
      ]
    ],
    "callerAngularToleranceDegrees": 10
  },
  "output": {
    "compatibleCallerSampledDatesYears": [
      100
    ],
    "sampleAngularDifferencesDegrees": [
      0,
      90
    ]
  }
}

Limitations and assumptions

Sampled compatible dates can be multiple and are distinct from a continuous calibrated age interval. Apply the exact scope and assumptions explained above.

All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.

Alternative or Complementary methods

Use C14 Age From Activity Calculator for a related task: Radiocarbon activity supports an exponential age under a chosen half-life convention.

Use Uranium-Series Speleothem Age Calculator for a related task: Uranium-series dating relates activity ratios to decay under a closed-system model.

References

Archaeomagnetic Date Lookup — tool.io

Similar or alternative tools

C14 Age From Activity Calculator
Radiocarbon activity supports an exponential age under a chosen half-life convention.
Uranium-Series Speleothem Age Calculator
Uranium-series dating relates activity ratios to decay under a closed-system model.