Table 3.

Summary of lithostratigraphical criteria applied to anthropogenic deposits

Lithostratigraphical criteriaSatisfied by Anthropogenic deposits?Examples of effective situationsExamples of exceptions/challenges
Law of SuperpositionYes – mostlyMost terrestrial deposits, resulting from the sequential emplacement of made ground including heritage depositsDeposits related to subsurface engineering and storage including back-filled cavities and injected material (i.e. anthropogenic ‘intrusives’ or ‘anthroturbation’); lithodemic classification may be appropriate
Original lateral continuityRarely – although ‘yes’ if broad scales consideredDeposits related to large-scale urban or industrial expansion (e.g. deposits associated with coalfield development); deposits associated with major socioeconomic or environmental drivers including conflict and climate change adaptation (e.g. flood defences)Most deposits related to site-scale processes; deposits that result from the infilling of surface excavations. NB: in all cases, lateral continuity is a function of the scale of the study and the lithostratigraphical resolution used
Lithological distinctionYesDeposits imported from diverse supply areas; deposits incorporating characteristic (ideally time-varying) novel materials; deposits composed of contrasting proportions of natural sediment, novel materials and reworked natural depositsMultiple deposits composed of locally derived natural material; deposits sourced from lithologically similar supply areas; deposits composed of reworked anthropogenic deposits
Definable type section/areaRarelySpatially extensive surficial deposits encountered in subsequent ground investigation boreholes; deposits classified as heritage deposits for which exposures are preserved. NB: type section definition of anthropogenic deposits may be simpler in the geological futurePoor natural exposure of deposits; restricted spatial extent may limit access to type sections/areas; extensive reworking and remodelling of deposits may prevent long-term preservation of type sections/areas
Hierarchical framework and namingYes – if broad scales consideredDeposits exhibiting broad lithological and stratigraphical characteristics that are indicative of particular novel environments, and may be grouped accordingly (see Table 2 for examples)Anthropogenic units require broader ranges of thickness and lithological variability than natural units of equivalent status; anthropogenic deposits do not satisfy stipulation for original lateral continuity