##  [Stratigraphic Thickness](/stratigraphic-thickness-0) 

 Definition

The vertical distance measured from the base to the top of a stratigraphic unit or archaeological layer, expressed in linear units and referenced to a specified local vertical datum; it records the layer's present vertical extent at the point of measurement.

 

 

 

 

 

 





## Principle

Principle

Measured thickness, when combined with plan measurements, determines the unit's contribution to deposited volume; because thickness commonly varies across a unit, representative sampling or integration is required for volumetric estimates.

 

 

 

 

 





## Demonstration

Demonstration

Illustrative scenario — Situation: In a trench, the recorded top of Layer A is 0.30 m below the site datum and the base is 1.20 m below datum. Recognition: The archaeologist identifies a coherent layer bounded by those surfaces. Action: Compute thickness = base depth − top depth = 1.20 m − 0.30 m = 0.90 m. Consequence: That thickness value enters calculations of Layer A's volume when multiplied by its plan area or used in three‑dimensional models.

 

 

 

 

## Misapplication

Misapplication

Treating a single point measurement as the layer's uniform thickness across the site; this ignores lateral variation and can misestimate volume and deposition history.

 

 

 

 

 





## Consequence

Consequence

An inaccurate thickness estimate causes proportional errors in volume calculations, artifact density estimates, and interpretations of depositional rate or sequence; those downstream analyses therefore depend on explicit sampling strategy and datum.

 

 

 

 

## Reversal

Reversal

When strata are tilted, folded, or laterally truncated, vertical thickness (measured parallel to the site vertical) differs from geological 'true thickness' measured perpendicular to bedding; in those conditions vertical measurement may not represent original depositional thickness.

 

 

 

 

 





## Boundary

Boundary

Clearly within: a horizontally bedded occupation deposit with consistent top and base in a trench. Boundary case: an irregular lens whose top and base pinch out rapidly across short distances. Clearly outside: a point elevation measurement (datum) or the depth to an isolated artifact unrelated to a defined stratigraphic unit.

 

 

 

 

 





## Semantic Tension

Semantic Tension

Practical vertical measurement (ease, archaeological convention) ↔ geological accuracy of true (perpendicular) thickness when structural deformation exists.

 

 

 

 

 





## Synthesis

Synthesis

Stratigraphic thickness is an operational, datum‑dependent measurement whose interpretive value requires explicit recording of reference surface, sampling locations, and awareness of lateral variability and post‑depositional deformation.