Proposal to add anthrostratigraphic and technostratigraphic units to the stratigraphic code for classification of anthropogenic Holocene deposits

Anthropogenic surficial deposits are formed from Holocene and older deposits that have been so modified by human activity that their original form is unrecognizable. Because their characteristics are fundamentally different from those of natural origin, the creation of special stratigraphic categories seems justified. Two new material categories are proposed for the stratigraphic classification of anthropogenic deposits. An anthrostratigraphic unit (ASU) is defined as a stratiform or irregularly shaped body of anthropogenic origin in the sedimentary record distinguished and delineated on the basis of lithologic characteristics and/or bounding disconformities. An anthropogenic origin is indicated if the deposit (1) lies beneath an anthropogenic landform, (2) contains artifacts, (3) shows evidence of artificial mixing or other human disturbance, and/or (4) was imported from offsite and is allochthonous. The basic ASU is the anthrostratum, defined as a mostly stratiform body of artificially mixed earth (rock...