Stratigraphy Volume Calculator

A stratigraphic layer's thickness commonly varies across an excavation unit due to natural slope, differential compaction, or prior disturbance, so measuring at all four profile walls and averaging gives a more representative depth than trusting a single corner or the center point, which could be unusually shallow or deep relative to the unit as a whole. The separate depth variation figure then tells you how much that single average number is actually hiding.

A large gap between the shallowest and deepest corner measurement suggests the layer's boundary is sloped, disturbed, or irregular rather than flat and consistent, which is exactly the situation the slope correction percentage exists to compensate for. A high depth variation alongside a low slope correction setting is worth double-checking, since it may mean the correction percentage entered doesn't fully reflect how irregular this particular unit's layer actually is.

That rate reflects careful, controlled archaeological excavation with hand tools, stratigraphic documentation, and artifact recovery as work proceeds, which is dramatically slower than mechanical earthmoving precisely because the goal is preserving contextual information, not just removing soil. Actual rates in the field vary with soil compaction, artifact density, and how much documentation a given context requires, so treat this as a reasonable planning baseline rather than a fixed rule.

Screening every bit of excavated soil through fine mesh is often impractical at the volumes a full excavation produces, so many projects screen a representative sample or apply screening selectively to contexts most likely to yield small artifacts, with the other portion examined by eye during excavation instead. The 50% assumption here is a common field compromise, and a project's actual research design may call for screening more or less than that depending on what the investigation is trying to recover.