Where in the hell am I?

December 29, 2009

Lab work last week

Filed under: archaeology, archeology, East Texas, Texas — Tags: , , , , , , — John @ 11:09 am

Me washing flakes

Originally uploaded by texasrobo

Never got around to blogging about Christmas week. All of the big projects were on break, so most everyone was in the office. I thought I might be working on making changes to the report from hell, but instead I got to work on artifact processing from the test excavations in East Texas.
When artifacts are collected in the field, they’re usually pretty dirty (almost goes without saying). One of the first things we do in the lab is to wash the artifacts. Different types of artifacts get cleaned in different ways, and this can change with different jobs depending on the proposed scope of analysis. Lithic debitage (ie stone flakes) is cleaned with a toothbrush and tap water. Bone is usually cleaned with distilled water, although I don’t really know why. Ceramics are either cleaned with distilled water or dry-brushed. Groundstone artifacts are generally dry-brushed. These artifacts are sometimes analyzed for residue traces, which would be washed off if water was used. Stone tools are also sometimes left uncleaned for residue analysis.
After this is done, the artifacts are put on a screen to dry. One of our drying racks is in the background of the photo. The artifact bags have identifying tags in them (or ID info written on them), which we put with the artifacts to keep from getting mixed.
After the artifacts are dry, they are counted and bagged, with the results going into a specimen inventory. This is usually done by hand in the lab, and then entered into Excel or Approach. The specimen inventory contains the data used for the basic level of analysis, such as comparing artifact counts at similar depths or locations across the site.
I should say that while the washing and counting is happening, the artifacts are being examined for possible tools or diagnostic features that were not noted in the field. This is my favorite part of the process, since it’s kind of like a second level of excavation. Something that looks like a oddly broken flake when covered in mud will be an obvious projectile point fragment after being cleaned (see note in photo).
Once all of the washing, counting, and sorting is done, the artifacts are put into clean plastic bags for future curation. New, clean tags are written in pencil with all of the locational and identification information. The artifacts are then ready for curation, or for analysis.
For this particular project, we’re sorting the lithic debitage during the processing. The criteria are material type (ie chert, petrified wood, quartzite), and presence or absence of cortex. We’re also supposed to pay really close attention for edge-modified flakes. This is not easy, as petrified wood has a wide range of looks and quality, and is difficult to tell if it’s modified. It’s also a bit tedious, as you might have a bag with 4 flakes, all of which are different, meaning you have to write out four tags and make four entries in the specimen inventory. It’s almost as boring as it sounds. (or more boring, depending on who you ask).
I’ll be spending the last day of 2009 doing this last step.


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