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Archive for June, 2011

Spring 2011

28 Jun

The Mammoth News

Spring 2011, Volume 23

 

Field Work

We started the term by setting out a grid of points, spaced a meter apart, on the ground surrounding our excavation site for running an earth resistivity survey, one remote sensing method that could possibly help us find where some of the missing bones are located. Dr. John Sexton from Southern Illinois Carbondale and a few of his students taking a class in geophysics brought their equipment on the first Saturday of the term to run the survey. Unfortunately the resistivity equipment did not function properly, so we ran a magnetic survey. Since Benny’s bones don’t appear to have iron minerals in them, we didn’t expect to get usable results with this method, but it showed my students the process involved in careful data collection in the field. They also learned how challenging it can be as equipment failure is an unfortunate part of field work at times. Laying out the grid was a good exercise too.

We decided to dig to the south this term, taking the entire wall back half a meter. We had our Facilities crew remove the upper terrace of dirt, then we proceeded with pick axes and shovels to remove the lower 1m to near the bone level. We moved right through the bone level without finding any bones for the first time this term. Next term we’ll try a different direction.

Lab Work

Postcranial Bones

After finishing the south wall without finding any new bone, we moved into the lab, where the students were guaranteed to find bone as they worked on two clusters of bones removed from the pit in 2004. They learned how to remove the plaster field jackets and then worked from the underside of each piece removing matrix to expose the bone. One cluster revealed two of our best preserved and longest ribs found to date. The other cluster contained two smaller and not so well preserved ribs, a couple of rib pieces, and a poorly preserved thoracic vertebra. We also cleaned an isolated thoracic vertebra.

Exhibiting Benny

I have been getting quotes for mounting and displaying the skull block in the atrium of the Science Center and building a display of the rest of the mammoth upstairs where the mammoth lab currently is in the Interpretive Center. We will need to have a major fundraising effort before we can begin the first task of mounting the skull block. If any of you are interested in contributing to this effort, please contact me. Many decisions are yet to be made regarding the best way to proceed with this phase of the project. I’ll keep you posted.

Outreach

Visitors

We had 217 visitors come for tours of the excavation site, lab, and skull block. These included Principia College parents, families from St. Clair County Christian Home Educators, a group of the Newcomers and Neighbors of Edwardsville/Glen Carbon, IL, Wolf Scout Den #2 Pack #31 in IL, various senior citizen groups touring the campus, and occasional drop-ins.

Talk

Janis Treworgy gave a talk about our mammoth project to the St. Louis Rock and Gem Society in March 2011.

Summer News Flash!

An alert outside contractor, Don Lewis, working on the water main project on campus found an unusual white rock-like specimen with a very well preserved spruce branch imbedded in it while they were removing Peoria loess, a uniform silt deposit, from one of the trenches. The spruce needles are incredibly fresh for being encased in this indurated material, indicating that they must have been buried quickly, like our mammoth. The white matrix may be a relatively hard clay with some dolomite (slow fizz with dilute HCl), and may be a deposit in an ancient (ice age – Quaternary) small pond present in the area. The trench is right next to the road and just down slope of the women’s softball field (3rd base line) so it seems unlikely that the loess is in place, but we haven’t ruled that out yet. That would make the sample much more valuable to us.

My husband, Colin, and I met the contractor and his family the next day, Saturday, at the college to look at the specimen and figure out what it was. We scraped a vertical section in one wall of the trench to get a fresh surface of the loess in order to sample it at various measured depths. We found a couple of lenses of soft clay in the loess, which is unusual to find in the Peoria loess, suggesting that the loess is fill material. The contractor and his family all participated in helping us measure the depths, sample the loess, and take notes. It was a great educational opportunity! I then gave them a tour of the mammoth site, lab, and skull block, which they loved. We are grateful to Don for his alertness.

I have contacted experts at the Illinois State Museum and Illinois State Geological Survey to determine interest in the specimen. Eric Grimm, a palynologist (studies ancient plants) at the ISM, and Dave Grimley, a Quaternary geologist at the ISGS, are excited by the photos I sent them of the specimen, but concerned about whether the loess is in place. If it is in place, we will get a radiocarbon date from the spruce needles. It also may be possible to get DNA from the specimen so my colleague Chrissy McAllister has taken the sample to Saint Louis University where it is being stored in a freezer that maintains a constant temperature of -20° C. If we decide the loess is in place, I will likely have my fall mammoth class help auger a hole adjacent to the trench to determine exactly where the specimen was found stratigraphically – where in the Peoria loess it occurred. This will help us know if it was from the same time period as our mammoth. I’ll keep you posted as we learn more.

-Janis Treworgy

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