Monday, September 30, 2013

Cheirurus niagarensis Trilobite Fragment

Previously images of an unprepped Cheirurus niagarensis trilobite pygidium was shown (see this post).  Recently, the fossil was cleaned using a sand abrasion technique.  These pictures show the results. First image fossil is photographed wet to enhance contrast. Fossil was found in the Waldron Shale of Clark County, Indiana, USA. It is dated to the Silurian Period.

The second shows a before and after cleaning images of the fossil. When cleaning I wear a respirator to keep silicate dust from getting to my lungs. Just looking at these images brings the memory of a smell of the rubber face piece. It is interesting how smells can get associated with tasks one does during the day.

Cleaning fossils takes patience and some strategy on how to approach the fossil to clean it. I was a little too ambitious on the top of this fossil thus wearing off the top thorax sections with the sand stream. Still it is nice to see more shape and detail of this fossil fragment. The Waldron Shale is easier to clean since it is soft and you can see immediate progress at removing it. During my cleaning session, I went through 3 canisters of sand while working on maybe 10 fossils before stopping. Thanks to Kenny for letting me use his cleaning equipment and help with removing matrix with an air scribe.