Saturday, August 24, 2013

Earth Discovery Day - August 2013

Today was Earth Discovery Day at the Falls of the Ohio State Park in Clarksville, Indiana. It is an event that focuses on educational activities for public. I have been volunteering over the last several years and it is a good feeling helping young students learn more about the mineral world around them while teaching about the fossil world of the past. Even though I have been really busy teaching, it is good to help out at an event like this.

The fossil pile was sparse in finds this year but the mineral pile while very dusty was a mountain of exploration for those willing to search for buried mineral treasure. The material is from a fluorite processing mill in southern Illinois that processed minerals from that area. Normally one sees four types of minerals: fluorite, barite, calcite, and sphalerite. The fluorite is usually purple, yellow or clear. Occasionally, green and blue fluorite will be found. A child found a nice fluorite cube corner shown in the first picture above. It has some nice purple phantom cubes that show through when held up to a light source.

Another child found a greenish-blue fluorite fragment while another found several aqua blue fluorite pieces. My challenge to visitors is to find pieces like this and usually about 4-6 specimens are found during my volunteer shift.

I was also told some material from China was processed there as well. So I am not sure what that might look like. A red or crimson colored rock was being found this year that was not seen in past years. It might be something from China. It is thought to be some type of reddish fluorite.

Fossils found were a number of brachiopods, corals, and snails from the Devonian fossil pile. The Silurian pile was being a bit more stingy. It did yield some nice brachiopods, a trilobite fragment, and a cephalopod fossil. Silurian Period Waldron Shale fossils are as shown: probably the tail (pygidium) of an Arctinurus sp. trilobite (I think it is upside down), next a fragment of a shell of a Dawsonoceras cephalopod, third is the index fossil of the Waldron Shale Eucalyptocrinus crassus crinoid calyx cup, and last an uncompressed Leptaena sp. brachiopod that has Cornulites sp. worm tubes on it.