Anthropogenic Soils in Archaeological Settings

Abstract

In addition to the Plaggic and Pretic Anthrosols discussed in Chap. 7, four other types of anthropogenic soil can be distinguished at archaeological sites: (1) Midden, (2) European Dark Earth, (3) Cemetery, and (4) Burial mound. Midden soils are classified as Hortic Anthrosols whereas burial mound soils are Spolic Technosols. Cemetery soils are Anthrosols, but they require a unique qualifier which has yet to be defined in the WRB. European Dark Earth refers to a type of buried soil (pa-leosol). All contain artifacts and are often black as a result of elevated levels of humin or black carbon (charcoal). Kitchen midden and midden-mound soils characterize archaeological sites where organic (food) wastes from human occu-pation were deliberately dumped. They have P-rich topsoils which were the inspiration for the anthropic epipedon as originally defined in U.S. Soil Taxonomy. Shell-midden and other types of midden soils may or may not be P-rich. Midden soils are typically the overthickened *A horizon of a natural soil, and often have elevated levels of pH, exchangeable bases, and carbonate content such that they are classified in a different soil order from that of local natural soils. European Dark Earth paleosols probably represent the buried *A horizon of one or more soils, found beneath the oldest parts of London, England, and other European cities dating from the late Roman or Medieval periods (5th to late 11th century). European Dark Earth resembles a Hortic Anthrosol, and was formed partly at archaeological sites of human occupation, and partly as the result of agricultural (plaggen?) activities. Grave soils are distinguished by a unique type of subsurface horizon formed by the residual accumulation of organic matter derived from the decomposition of a corpse, accompanied by an artifact assemblage comprised of grave goods. This (" necric ") horizon has not yet been defined in the WRB, hence classification of grave soils remains problematic. Studies of burial mound soils in North America showed that cambic horizons were well expressed in anthropogenic soils *500–2000 years old, proto-argillic horizons were evident after *2000– 2500 years of pedogenesis, and argillic horizons were formed in approximately 2500–3000 years.