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Archive for June, 2005

Spring 2005

28 Jun

The Mammoth News

Winter and Spring 2005, Volume 8

Lab Work

Chrissy Wakeling, my teaching assistant, continued working in the lab during the winter and basically finished cleaning the right scapula (shoulder blade) and the left humerus (upper arm bone). At the end of the term, Jeff Saunders of the Illinois State Museum, Chrissy and I made the storage jacket for the humerus.

Field Work

Prior to the term, the Facilities Department extended the shelter over our excavation another sixteen feet to the west, the area that we think still has mammoth bones. This area will likely be the focus of the fall and future classes.

On the first day of Spring term, the class uncovered Benny and found him to be in good condition after his third winter of being buried by insulation and Styrofoam peanuts.

One of our goals this term was to take down a small section of the west wall so that we had a straight wall across the pit. This involved pick-axe work until we got near the bone level. Once there, we switched to scraping the dirt with trowels keeping a sharp eye out for bone, but finding a lot of decayed roots that look like bone at first glance. Eventually we did find two small, not well preserved bones – possibly a cervical (neck) vertebra and a podial (foot or hand bone). This was exciting and gave us a chance to pedestal and plaster jacket bone! By the eighth week we had completely leveled this area.

Our BIG GOAL the year is to get the skull block out of the ground and into the lab. The skull block includes the two tusks, the two upper teeth, and the skull that is still buried. We estimate that the block, with the enclosing dirt (loess) and the plaster jacket that we will add, could weigh several tons (one cubic yard of loess weighs about 1.5 tons, according to the engineering geologists who visited the site early this summer). We have 3-4 cubic yards of loess and bones.

The class dug a one-yard wide trench down (about a yard) around the skull block. The bottom of the trench is five feet below the top of the tusks. That is about 7 cubic yards of loess – or at least 10 tons. That’s how many tons of dirt we carried out of the pit by the bucket load this term! (Students: “I think we should get PE credit for this class!”)

At the end of the term, we started to tunnel under the skull itself in preparation for plaster jacketing that area. We have this great new tool – an 8″ long auger that is on a rod 25″ long that fits in an electric drill. It is designed for digging holes in soil to plant bulbs in, but it is very effective in tunneling under mammoth bones!

The rest of the skull block work is going to take place this summer because of the need for uninterrupted blocks of time, especially as staff from the Facilities Department get involved.

Lab Work

While our emphasis has been on the field work this term, we did get some lab work done as well. Stacey Wallace, my teaching assistant, supervised students in the lab. We finished cleaning and consolidating the one side of the left femur (upper leg bone), a slow and tedious job, and then we made the storage jacket for it – this was the first class to get to participate in this activity. We also worked on removing the second half of the field jacket from the left humerus and starting to clean the bone.

Grain-Size Analysis

We had a special project going on this term as well. Two students who are geology minors sampled a vertical section of the loess from 50 cm below the level (paleosol) on which the bones are found to 110 cm above the bone surface. They then did a grain-size analysis of the samples. The procedure is quite detailed and took most of the term. We are still analyzing the results. We are grateful to Dr. David Grimley of the Illinois State Geological Survey for guiding us in this project. Our hope is to see if there is an increase in grain size directly above the paleosol in the interval that represents the sediment that buried Benny. This might suggest that there were stronger winds during that period of time. If there is a correlation, stronger winds could explain (1) his demise (buried food source, breathing difficulties, … cf. to the Dust Bowl era) and (2) the rapid burial that would help explain the fairly good bone preservation for burial by wind-blown sediment.

Outreach

Visitors

During the spring term we hosted tours for nearly 1200 people, including 500 one Sunday when the college had a campus-wide Open House for the surrounding communities. The other 700 were mostly students from area schools as well as some parents and Prin Club officers.

-Janis Treworgy

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