Analysis of Plant Remains

Lab 7Introduction to Environmental Archaeology

Environmental Reconstruction

Botanical remains offer clues to diet, environment, seasons, and changes in biotics

When combined with landscape studies (and ethnographies) botanical information can provide evidence of past environment

Terms

Linnaean taxonomic system Archaeobotany, paleobotany Macro-plant remains Micro-plant remains Chemical remains

Goals

Archaeologists seek remains of plants at sites through careful collection of soil samples

Techniques vary but the most common approach is flotation or washing soils. Both methods allow processing of large volumes of soil (pounds rather than ounces)

Identification

Difficult Soil separation allows sorting of

botanicals from insect, mineral, and other soil components.

Use of reference collections Online reference collections

Special data sets Phytoliths Pollen Both can yield

significant information about past environments. Although not indestructible they are very durable until brought to the lab.

Phytoliths

Procedures Teams of four (5 teams) Teams will be assigned a flask or bag of

soil. Record the flask/bag number The soils will be wet-screened through

standard mesh separation sieves. [Small mesh retains smaller sized botanicals, etc., allowing larger material to pass through to next screen size. Process can be run in reverse].

The goal is to collect material graded by size and to examine the material under a microscope for basic identification (see page 279-80 in text. We will use the same form. The team will be responsible for the forms. Individual write-ups should be collected as a packet and attached to the lab forms.

You will need to make microscope slides or review material in petrie dishes.

Weigh your sample

Dry sieving in a stack.

Wet sieving in a single screen.

In this exercise it will not be required to identify actual family, genus, species but you will have a chance to try by using a variety of online reference collections. Bonus points for successful IDs.

If we can get the high power digital microscope to work we will also capture images.

Procedural notes Washed soils will need to be air dried. Use

the coffee filters for small samples. Trays for team samples will be available in

the Lab Do not discard anything. Soils that pass

through all sieves can be collected for drying.

A known quantity of a reference seed will be included in your sample to evaluate recovery efficiency.

Final note Each team will have a designated time to

carry out the soils washing. The expectation is two teams for each lab period will complete their sample. You do not have to use all sieves I the set. Three or four should be enough.

We will discuss interpretation and sample storage in a future class period.