Midden - An Archaeological Garbage Dump

Why is an Ancient Trash Pit an Archaeologist's Favorite Discovery?

Stone axe and chip found in a midden in New South Wales
Stone axe and chip found in a midden in New South Wales. Auscape / Getty Images

A midden (or kitchen midden) is the archaeological term for trash or garbage heap. As an archaeological feature, middens are localized areas of dark-colored earth and concentrated artifacts, that resulted from the deliberate discard of refuse, food remains and domestic materials such as broken and exhausted tools and crockery. Middens are found everywhere humans live or have lived, and archaeologists love them.

The name kitchen midden comes from the Danish køkkenmødding (kitchen mound), which originally referred specifically to coastal Mesolithic shell mounds in Denmark. Shell middens, primarily constructed of the shells of molluscs, were one of the first types of non-architectural features investigated in 19th century pioneering archaeology. The name "midden" stuck for these hugely informative deposits, and it is now used globally to refer to all kinds of trash heaps.

How Does a Midden Form?

Middens had multiple purposes in the past, and still do. At their most basic, middens are places where rubbish is placed, out of the way of normal traffic, out of the way of normal sight and smell. But they are also storage facilities for recyclable objects; they can be used for human burials; they can be used for building material; they can be used to feed animals; and they can be the focus of ritual behaviors.

Some organic middens act as compost heaps, that improve the soil of an area. Chesapeake Bay shell middens on the Atlantic coast of the United States (Cook-Patton et al.) have been found to have significantly enhanced local soil nutrients, especially nitrogen, calcium, potassium and manganese, and to have increased soil alkalinity.

These positive improvements have lasted for at least 3,000 years.

Middens can be created at the household level, shared within a neighborhood or community, or even associated with a specific event, like a feast. Middens have different shapes and sizes: size is a direct reflection of the length of its use-life, combined with how much material in it is organic or can be recycled. In historic farmsteads midden deposits are found in thin layers called "sheet middens", the result of the farmer throwing out scraps for the chickens or other farm animals to pick over. But they can also be enormous: modern middens are known as "landfills".

What's to Love about a Midden?

Archaeologists love middens, because they contain the broken remains from all kinds of cultural behaviors. Middens hold food stuff and broken pottery; exhausted stone and metal tools; organic matter including charcoal suitable for radiocarbon dating; and sometimes burials and other ritual behaviors. In some cases, midden environments have excellent preservation of organic materials like wood, basketry, and plant food.

A midden can allow the archaeologist to reconstruct past human behaviors, particularly things such as relative status and wealth and subsistence behaviors.

What a person throws away is a reflection of both what they eat and what they won't eat.

Types of Studies

The study of middens are sometimes a source of indirect evidence for other forms of behavior. For example, Braje and Erlandson compared abalone middens in the Channel Islands, comparing one for black abalone, collected by historic period Chinese fishermen, and one for red abalone, collected 6,400 years ago by Archaic period Chumash fishermen. The comparison highlighted different purposes for the same behavior: the Chumash were specifically harvesting and processing a wide range of edible foods, focused on the abalone; while the Chinese were solely interested in the abalone.

Another Channel Island study (by Ainis et al.) looked for evidence of the use of sea kelp. Kelp were incredibly useful to prehistoric people, as cordage, nets, mats and basketry, as well as edible wrappings for steaming food--in fact they are the basis of the Kelp Highway Hypothesis--but kelp just doesn't preserve well.

Ainis and colleagues found tiny gastropods in a midden that are known to live on kelp, and used those to argue that the kelp was being harvested.

Paleo-Eskimo in Greenland, Late Stone South Africa, Catalhoyuk

A Paleo-Eskimo midden at the Qajaa site in western Greenland is an amazingly well preserved midden protected by permafrost. Studies of that midden (Elberling et al.) revealed that in terms of thermal properties such as heat generation, oxygen consumption and carbon monoxide production, the Qajaa kitchen midden produces 4-7 times more heat than natural sediment in a peat bog.

Lots of studies have been conducted on the Late Stone Age shell middens on the coast of South Africa, so-called megamiddens. One (Helama and Hood) has looked at molluscs and corals as if they were tree rings, using variations in the growth rings to yield the rates of midden accumulation. Jerardino looked at micropaleoenvironments in the shell middens, to identify sea level changes.

At the Neolithic village of Çatalhöyük in Turkey, Shillito and colleagues used microstratigraphy--detailed examination of the layers in a midden--to identify fine layers interpreted as hearth rake and floor sweeping; seasonal indicators such as seeds and fruits; and in situ burning events associated with pottery production.

Sources

This glossary entry is a part of the About.com Guide to Archaeology Site Types and part of the Dictionary of Archaeology.

Ainis AF, Vellanoweth RL, Lapeña QG, and Thornber CS. 2014. Using non-dietary gastropods in coastal shell middens to infer kelp and seagrass harvesting and paleoenvironmental conditions. Journal of Archaeological Science 49:343-360.

Braje TJ, and Erlandson JM. 2007. Measuring subsistence specialization: Comparing historic and prehistoric abalone middens on San Miguel Island, California. Journal of Anthropological Archaeology 26(3):474-485.

Cook-Patton SC, Weller D, Rick TC, and Parker JD. 2014. Ancient experiments: forest biodiversity and soil nutrients enhanced by Native American middens.

Landscape Ecology 29(6):979-987.

Elberling B, Matthiesen H, Jørgensen CJ, Hansen BU, Grønnow B, Meldgaard M, Andreasen C, and Khan SA. 2011. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland. Journal of Archaeological Science 38(6):1331-1339.

Gao X, Norwood M, Frederick C, McKee A, Masiello CA, and Louchouarn P. 2016. Organic geochemical approaches to identifying formation processes for middens and charcoal-rich features. Organic Geochemistry 94:1-11.

Helama S, and Hood BC. 2011. Stone Age midden deposition assessed by bivalve sclerochronology and radiocarbon wiggle-matching of Arctica islandica shell increments. Journal of Archaeological Science 38(2):452-460.

Jerardino A. in press. Water-worn shell and pebbles in shell middens as proxies of palaeoenvironmental reconstruction, shellfish procurement and their transport: A case study from the West Coast of South Africa. Quaternary International: in press

Koppel B, Szabó K, Moore MW, and Morwood MJ. in press. Isolating downward displacement: The solutions and challenges of amino acid racemisation in shell midden archaeology. Quaternary International: in press.

Koppel B, Szabó K, Moore MW, and Morwood MJ. in press. Untangling time-averaging in shell middens: Defining temporal units using amino acid racemisation. Journal of Archaeological Science: Reports in press.

McNiven IJ. 2013. Ritualized Middening Practices. Journal of Archaeological Method and Theory 20(4):552-587.

Shillito L-M, Matthews W, Almond MJ, and Bull ID. 2011. The microstratigraphy of middens: capturing daily routine in rubbish at Neolithic Çatalhöyük, Turkey. Antiquity 85(329):1027-1038.