Workshops in Archaeology 2015

the process and results of water separation at an archaeological site

Much of what we know about Native American plant husbandry is the result of many years of specialized investigation through the archaeological recovery process of separating carbonized debris from pit soil via water immersion. This process is called flotation the principal method used by archaeologists and paleo-ethnobotanists to recover plant parts, especially seeds and other small fragile remains from archaeological contexts. Through flotation, specimens are recovered, identified and studied to better understand the subsistence behaviors of the people who consumed them. Additionally, starch and pollen grains and phytoliths are minute residues associated with prehistoric diet. Thus, through a careful detailed study of these plant related components, hidden information is revealed relating to human diet.  On a regional, level this research has broad implications that have the potential to greatly enhance our understanding of cultural adaptations and plant use/consumption of prehistoric native groups who once occupied the Pennsylvania landscape.

various starch grains from archaeological sites

At first blush growing crops from weeds may seem a weird concept but cultures around the world have been doing just that for thousands of years. Take for example the food patterns of early Meso-American societies where various strains of grass, by way of eco-human modification and natural selection developed into the primitive form of maize called tseosinte. Over time this crop food, became the flint and dent varieties of maize. Along with beans and other Mesoamerican derived plant foods likely spread into the Mississippi Valley and on to other parts of North America at an early period where they became valuable food products in the Native American and Euro-American diet.

squash phytoliths

Gourds were grown in the central Mississippi valley around 4500 years ago and gourd rinds dating approximately to this period have been recovered from archaeological contexts in the central Susquehanna valley at the Memorial Park Site. Certain weed seeds carefully selected for their robustness and nutritional qualities were replanted setting the stages for incipient Eastern North American horticulture. Though archaeologically unknown or rarely identified for much of Pennsylvania other weed crops were Amaranthus a.k.a. pigweed ,Chenopodium a.k.a. goosefoot, Iva a.k.a. marshelder and Helianthus a.k.a. sun flower among others.

multiple pollen grains imaged under SEM scope

Horticulture or garden farming played a significant role in the sustainment of a dependable food base. Climate fluctuations occurring at certain periods in human prehistory/history, caused by uncontrollable rises and declines in solar activity, volcanic eruptions and trade wind temperatures, bore directly on ocean current patterns. Some or all of these factors were contributory to the Little Ice Age and the Neo-boreal climatic period between 1350-1850 AD. Their lasting effects were felt in many parts of the world until the early 19^th century when conditions again improved.

Until the arrival of domesticates with modifications in the environment human plant food consumption likely did not change much though some plant foods were only available seasonally. Foods such as berries and a wide range of nuts only ripened during certain times of the year (i.e. the fruiting season of summer and the nutting season of late autumn). In their absence edible parts of soft stemmed plants that emerged in early spring were processed and eaten along with roots and tubers from mud banks and wetlands. The latter of which were accessible over much of the year. Some of these plant products thus harvested were eaten directly or stored for later consumption added variety to the daily menu of native people.

The appearance of maize (circa 800 AD) and beans (circa 1300 AD) on Pennsylvania’s prehistoric landscape significantly contributed to changes in Native American demographic patterns. Small habitation sites grew into large fortified settlements supporting many people. Surrounding many of these settlements were extensive agricultural fields where corn, beans and pumpkins were grown. For much of Pennsylvania this subsistence strategy lasted until the system collapsed and many groups were dispersed in the mid-17^th century when foreign diseases arrived and Europeans focused their economic pursuits on land acquisition and the extraction of native resources. By the early 17^th century elements of the native diet were adopted by European immigrants and their presence can still be seen on the modern day dinner plate.

This has been a brief introduction on the use of plant foods in the Keystone State from “weed seeds to garden seeds”. The 2015 Annual Workshops in Archaeology Program is only a week away. This year’s theme is a topic of wide interest to many Pennsylvanians beyond the archaeo-botanical community. Experts with special fields of interest will be presenting and you can view the program by clicking on the program banner to the right at the top of this post. We hope to see you at the workshops on November 14^th.

For more information, visit PAarchaeology.state.pa.us or the Hall of Anthropology and Archaeology at The State Museum of Pennsylvania .