Thursday, April 7, 2011

Processing

Now everyone who hears about an excavation (dig) has the fantasy of BIG treasures! Gold! King Tut and all his belongings!

Sadly, and profoundly wonderful there is little of that, at least here in the Southwest! Digs bring forth human detritus that archaeologist study for past human behaviors.

For prehistoric digs we are talking broken ceramic pots, broken stone tools, broken pieces of shell, left over dinner in the form of bones. Sometimes there maybe something whole, which is a thrill especially if it is different such as a Hohokam finely etched shell amulet.

For every hour of excavation I think there are about 5 hours spent in the lab. Long hours!

To give you an idea of what happens to the ‘finds’ let’s follow an artifact from soil to report.

The site has been given a datum and it is ‘ground zero’ so to speak. All measurements are taken from the datum.

In your excavation pit you find a painted (decorated) sherd. This item is provenienced in-situ by you. In other words, it is placed within the world in its exact location: northing, easting, and elevation. Once this is done your sherd is given its own identifying number and placed in its own bag that has its own inventory number (field number).

On the bag you place site, item number, field number, date and again the provenience information-- northing-easting-elevation. And don’t forget your name or at least your initials. The bag is entered onto the log (inventory).

The bag goes into the lab right along with all the others for the day or days.

Your item is removed from the bag, carefully washed with a soft brush (usually a tooth brush) and water; rinsed then placed on a rack to dry. The bag is kept with the sherd. After the sherd is dry, about 24 hours, it and the outside of the bag go into a new clean, acid free, plastic bag.

Multiply those simple steps by 10,000, as that could be the number of artifacts removed during an excavation. One small dig I was on, we removed 27,000 artifacts and each one had to be handled separately.

Actually, the next steps are rather more involved as each artifact has to be labeled. We use a lazer printer to make the numbers on acid free paper --tiny numbers about font size 6-8. The tiny number is glued onto the artifact with Rhoplex. We use fine watercolor paint brushes to do this. The item is allowed to dry again before returning it to its bag.

Then comes the analysis. I can tell you it is a long process done by experienced and well trained/educated archaeologists. Items are looked at with a lens or a microscope. Some artifacts are sent out for separate analysis; an example would be Obsidian, that is sent to a laboratory for sourcing. Sourcing will tell you where the peoples you are studying got the material - how far they traveled or traded for the material.

Your decorated sherd may have the temper checked - petrographic analysis. The design will be looked at and matched with other decorated sherds from the site. Design matches will give a time frame (date) for the site. Petrographic analysis may tell you were your vessel was made.

Are you tired or bored yet?

I have spent hours processing artifacts, which includes: washing, tagging, re-bagging and correcting/doing the inventory and sometimes, data entry.

You start getting a ‘feel’ for the site - Hmmm lots of decorated pottery and it all looks alike - or Hmmm where did that come from? - that is different. Sometimes you make a discovery while processing. Sherds may refit together, or one that I had that was a thrill, 2 pieces of worked stone fitted together and formed a small, decorated breastplate. Each piece was from a different bag and area of the site!

At the end of a processing/washing day you will have shriveled hands, aching back and a fine tale or two to tell.

Or, as in my recent case, very orange nail beds from the red Georgia clay!

The archaeologist PI (Principal Investigator) then takes all the information that has been received/reviewed from other specialists and writes up the report. The report is usually VERY technical in that it may have charts, comparisons of artifacts from other sites, dating mechanisms and the list can go on.

If the site gets the News media attention the newspaper article may say, “Decorated sherd discovered and points to long term travel between x & y.”

You, although unmentioned, are a discoverer!

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