Geological stratigraphy

Giorgio Buccellati – July 2026

Geological stratigraphy

The concept originated in geology and has remained a core feature of this discipline, with a variety of methodological approaches having arisen in recent years. Catuneanu 2026 provides a comprehensive synthesis of eight distinctive types of geological stratigraphy, two of which are particularly relevant for archaeology.

Allostratigraphy (Catuneanu, chapter 8) focuses on the interface among the constitutive elements – the term “allo” in the name referring to the discontinuities and bounding surfaces that are found among, and are thus “other than,” the building blocks of the system, i. e., the lithological elements which can be defined morphologically. This correponds to the types of contact among elements in archaeological stratigraphy.
Sequence stratigraphy (Catuneanu, chapter 9) focuses on the dynamics of events as they can be assumed on the basis of repetitive conformities especially in their surfaces as evidence of erosion and deposition. This is the most recent trend in geological stratigraphy, whereas it has been at the center of archaeological stratigraphy since the beginning, particularly in its effort at relating space and time as part of the same continuum.

Interestingly, no substantive mention is generally made, in discussions of geological stratigraphy (besides Catuneanu 2026, see. e. g., Mardon 2021). This is in effect indicative of the fact that archaeological stratigraphy differs in its essence from geological stratigraphy, even though the starting point is the same. The difference is instructive, and it needs to be brought out. A comparison is certainly useful for archaeology, as one would think it should be for geology as well.

Geological vs. archaeological stratigraphy

Archaeological stratigraphic analysis differs in three respects from its geological counterpart, and it is a radical difference. What is at stake is both the nature of the data and the method of analysis.

Natural vs. cultural build-up

The dynamics of the formation processes as can be inferred from the record as found in the ground is altogether different. The geological record reflects relatively few natural processes that affect wide geographical areas, whereas the archaeological record reflects a multiplicity of cultural (and occasionally natural) events that affect well defined and generally well contained spaces.

In particular, cultural deposition presupposes both intentional and accidental events, and in the intentional events we can infer purpose and function.

The same and the unique

The geological record is built on sameness. A given lithological element, definable in terms of distinct characteristics, is the same at different points in the record, and this implies a regional or global tectonic event.

Archaeological stratigraphic analysis, on the other hand, is built around uniqueness. Each element, however minute, has a “dignity” of its own (Buccellati & Kelly-Buccellati 2026). This does not mean that there are no similar events that can have identical effects on elements, or that there are no similar phenomena to be identified in the record. Obviously, excavation of a pit or the construction of a structure such as a wall are similar and hence “repetitive” – and so is a conical cup similar to hundreds of other conical cups found dispersed in the “strata” that have been deposited at a given site. But each event and each element must be viewed in and of itself, as specific and unique. Similarity is not sameness.

Singularity is thus a distinctive feature of the archaeological record, and we must always be mindful of the uniqueness of each and every element that is exposed. This is not to say that we cannot generalize. Chronological horizons and typological assemblages are examples of how concrete single elements presuppose wider ranges into which they may fit. But each element retains its own particularity and must be treated as such.

The index and the whole

Any given point that is exposed in the geological record is an index to a wider whole: a given sedimentary facies, partly exposed at a given location, serves as an index to both a larger whole (the full sedimentary deposit that remains unexposed) and to a given event that caused the sediment to occur.

In the archaeological record, on the other hand, every single element is a whole in itself. As such, it needs to be seen first in its relationship to any other element with which it is in contact, and second with the typological universe proper to the culture from which it originates.

References

Burgess & al 2021

Cateneanu 2006, 2026

Mardon & al. 2021 esp. p. 111f

ChatGPT 2026-420

Wikipedia: Stratigraphy; Stratigraphy_(archaeology)