A group of scientists in the U.K. have studied anthropogenic soil formation in Orkney, a set of islands off the north coast of Scotland.
What is "anthropogenic soil"?
Just like it says, it's man-made soil.
Man-made? During the Neolithic or the New Stone Age?
Yes! It wasn't intentionally manufactured, you see. This soil is the result of collecting ash and human waste in a relatively barren area. It can be used to locate areas of human settlement, possibly deriving some information about the dates and even the diet of the inhabitants.
They did this research at Tofts Ness on the island of Sanday, in the far north-east area of the Orkney Islands. Ness means point in Orkney, where most of the geographical terms come from Old Norse. So, at Tofts Point on that outlying island.
Neolithic Orkney"Early Anthropogenic Soil Formation at Tofts Ness, Sanday, Orkney",
Journal of Archaeological Science "Organic geochemical evidence for the origin of ancient anthropogenic soil deposits at Tofts Ness, Sanday, Orkney",
The researchers are Ian Simpson of the University of Stirling, Stephen Dockrill of the University of Bradford, and Ian Bull and Richard Evershed of the University of Bristol. Their papers are aimed at different audiences, one appearing the Journal of Archaeological Science and the other in Organic Geochemistry.
Orkney is a group of islands off the northern coast of Scotland. The largest one is called Mainland, from the Old Norse name Meginland.
Yes, the island is called "Mainland". You leave the mainland of Europe and cross the English Channel to reach the island of Britain. By the time you get to the northern tip of Britain it feels like a mainland, and people refer to it that way when crossing to Orkney. Then the largest island in that group seems like a mainland in comparison to the small islands. Everything is relative.Neolithic toilets in Orkney
There are signs of human occupation going back to 6500 to 7000 BCE, and the Skara Brae settlement dates to 3500 BCE.
The local sandstone easily splits into useful sheets or plates, and driftwood and whale bones washed ashore to be used as roof beams. This cluster of homes built to a common design included a small "cell" believed to be a toilet, a very early example of an indoor toilet.
The Neolithic people left Orkney when environmental changes happened. Then the Pictish people settled the islands during the Iron Age, which was about 800-400 BC in Britain.
The Norsement made Orkney their headquarters by the 800s CE. Orkney and Shetland were formally Norse until 1468, when the Norwegian king Christian I pledged Orkney and Shetland to James III of Scotland as dowry for his daughter Margaret. Culturally, Orkney was Norse until at least 1800.
Tofts Ness is the northeastern peninsula on the northeasternmost island, so it is fully exposed to the weather. Wind-blown sands have buried the settlements, so it has one of the richest collections of archaeological sites in a group of islands known for its ancient sites.
They found a buried layer of dark loam soil, 35 to 75 cm thick and buried at various depths between wind-blown sand deposits.
Increased levels of phosphate along with distinctive sterol chemicals associated with human feces told them that these layers were the result of intentional human activity.
They believe it is the result of a mixed pastoral and crop-growing economy. Heather and grass would have been stripped from the ground and used as animal bedding and feed. The resulting composted turf and animal waste was then applied to the arable land areas as fertilizer for crop growth.
The stratigraphy (that is, analysis of the layers) and radiocarbon dating indicate that the process dates at least from the Bronze Age, and may have started during the late Neolithic.
All living creatures contain sterols, a class of chemicals of which cholesterol is one example. A variety are excreted in feces. The precise mixture depends some on what the subject ate, and more on what their body synthesizes and how their specific gut flora transforms that combination. Sterols are stable enough to be detected in soil after two millennia or more.
A high percentage of Coprostanol, also known as 5β-cholestan-3β-ol, indicates feces "of predominantly human origin". It is produced by intestinal bacteria acting on cholesterol ingested or biosynthesized by the host.Tracking Hannibal's elephants by their droppings Coprostanols in the Athens Agora The Roman Military Diet
Other similar chemicals can serve as biomarkers for other animals. For example, high levels of 5β-stigmastanol indicates ruminant animals or horses. Hannibal's elephants left a distinctive biochemical trail of their droppings on his epic passage through the Alps.
In this case, the proportions of stanols and bile acids found indicate a mix of mostly human plus maybe some pig feces in the man-made soil.