Radar

Friday, June 8, 2012

Four members of Team Mammoth left Iowa City at 1:30 PM and arrived at the mammoth site at 2:45. Frank Weirich and David Brenzel went to the dig area immediately and began preparing a grid for the Ground Penetrating Radar (GPR) survey while Holmes Semken waited for the land owner to return from work and Sarah Horgen who came from Ottumwa.  A film crew from William Penn University arrived shortly thereafter and all were onsite by 3:30.

We laid out a 12 meter by 12 meter grid (approx.) and Frank surveyed the site three times with a Mala ProEx ground penetrating radar system. The grid on each survey was crisscrossed, first E-W then N-S, at 1 meter intervals, using 250 MHz, 500 MHz and 800 MHz antennas. The 250 MHz antenna penetrates further but 800 shows more detail.The GPR yielded some interesting anomalies but the raw data cannot separate mammoth bones from logs, cache pits, rocks or graves. Frank will process the raw data using several radar data processing software packages in order to filter, amplify and otherwise clarify the images as well as proceed to generate 2 and 3 D images of the mapped areas. We hope to have some pictures and a preliminary analysis in time for our next dig Saturday, June 15. Information from Art’s cores will help correlate the different lines with stratigraphic breaks in the core samples. Frank plans to return during the next dig to field check the results and refine data levels. We're fortunate to have Frank Weirich donating his time to the project.

The camera crew from William Penn University’s Communication Research Institute said that their organization specializes in documentary film. Holmes asked if they would like to document the dig and they were most interested and agreed. They are aware that reporters from other organizations will visit the site.

The survey was complete about 7:00 PM.