​Archaeologists love trash! Why?


Archaeologists love trash! Why?

 
Trash is the great equalizer; rich or poor, everyone creates it. Examining trash opens a window to their everyday lives and there’s no doubt that future archaeologists will analyze the contents of our trash to see just how we lived in the 21st century.

One of my favorite types of trash deposits are middens. Middens are characterized by rich, dark, organic soils that are formed in layers. Their contents provide insight into how people made their living, what they ate and what types of plants and animals were available in their local environment.

But how do archaeologists investigate a midden in order to understand all of this?  First we excavate it carefully, screening and collecting artifacts and recording what the midden looks like. This involves taking pictures, making maps and describing what each layer of soil is like.  Then, soil samples from the midden are removed and put into bags. The bags are sealed and tagged with the exact location. These locations are also identified on the map. Without recording all of this, the soil has lost its context and is just a bag of dirt lacking any particular scientific use. Though it would make great fertilizer for your garden!

Soil sample tag
Soil sample tag
Soil sample
Soil sample

Next, the samples are brought to the lab for processing and analysis. Two types of processing are water screening and flotation. Both involve using lots of water and generate quite a bit of mud that needs to be cleaned up at the end of each work day.  Needless to say, we expect to get very wet and dirty when we do this work. But that’s a small price to pay to better understand the story behind the midden and the people who created it. Water screening involves putting a portion of a soil sample into a mesh screen and using a garden hose to gently apply water.  The water carries soil particles through the screen, leaving artifacts, food remains, plant matter and rocks behind.

Water screening dirtSoil ready to be water screened
Water screening, no dirt
Soil removed

Flotation puts the rest of the same sample into water and uses flowing water to bring lighter weight items like charred seeds, shells, fish scales and charcoal to the surface.  These lighter items flow into a wedding veil type fabric.  The remaining, heavier, items are put on small mesh screens and are water screened.

Flotation
Flotation process

After everything’s dry, it’s identified, separated into groupings, counted, weighed and perhaps sent off to specialists for further analysis.

Sorting
Thousands of tiny items to be identified and sorted 

What can these smaller items tell us?

Food remains can narrow down the time of year the midden was created. For instance, peaches are typically harvested from late July to the first part of September and are very perishable. So if you found a peach pit, it was probably thrown away soon after it was eaten. Furthermore, the Spanish introduced peaches to Florida 1500s and they were found in Virginia in the early 1600s. This gives us a rough span of time the midden could have been created; a late summer/early fall between 1500 and the present.  If we wanted to get more precise, the same pit could be sent to a specialist who might be able to narrow the year range even more.

Flint flakes also tell a story. Different types of flakes are produced during different manufacturing stages.  Bigger chunks and flakes are associated with the initial artifact processing stage. Smaller flakes are from more specific or refined artifact processes, such as resharpening tool edges. The type of flint can also tell a story. Is it local to the area where the midden was found or is it more exotic?  Did people have to travel long distances to get it and how could this travel affect social situations and infrastructure?

Stories are also told through the various styles of ceramics, buttons, bottles, even nails, changes in horse shoe styles and metal can pull tabs.

All of these clues build upon themselves and crack open that window to the past, presenting the story of the land and the people who lived there.

What do you think an archaeologist from the future would discover about you by looking through your trash?

 

Posted May 25, 2021
Topics: Historic PreservationArchaeology

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