Sampling Mud Down to 13,000 Years Ago to Shed Light on Mastodon's Grave

The two volunteers in the foreground are standing in a trench that reveals some of the soil layers in the excavation site that could reveal how the site was formed over the past 13,000 years or so--and how it fits in with the nearby bog that was once a glacial lake when the dead mastodon roamed its shores.   (Photo by Don Comis)

Pieces of mastodon tusk (left) and other bones (right) collected from the surface of the ditch area on April 26.   More complete bones should show up soon as we hone in on our quarry, during a dig that is in its third week.  (Photo by Don Comis)

On September 10, Ashland University's Dr. Nigel Brush sent me and other volunteers a link to Dr. Greg Wiles' latest blog (September 7) “on the sediment cores that were taken from the bog near the Morrow County (Ohio) mastodon site last Saturday, September 6.”  

Wiles will collaborate with the soil core team, giving his Climate Change students at the College of Wooster (Ohio) the opportunity of working with the cores over the next several weeks—a wonderful way to spend the first semester back at school!

The team—Dr. Tom Lowell and  his graduate student Stephanie Allard, at the University of Cincinnati, and University of Illinois student Jacklyn Rodriguez-- found many species of snails and possibly clams in one three foot (one meter) core sample of  lime-rich mud (clay “marl”).   In answer to one of the questions I e-mailed him after the September 6 dig, which I participated in, Dr. Brush said that that “Clay marls are light gray to whitish in color and are composed of a mixture of clay and small shell fragments of various organisms, such as gastropods (snails) and pelecypods (clams) that lived in glacial lakes.”

They team took samples—in 3-foot sections--down to 21 feet (seven meters).  The last 3-foot core sample represents the late glacial period, about 13,000 years ago, about the time when mastodons roamed the shores of the glacial lake that is now the bog.

The blog includes some nice photos, including one showing the soil layers (stratigraphy) in a trench cut in the nearby mastodon excavation area to locate the path of the machine that uncovered an 8-inch long mastodon tooth and pieces of other teeth and the jaw bone as it laid drainage pipe.

The caption says that “we hope to be able to link the bog cores to this site.  It may take a backhoe pit from the excavation to the bog to really understand how the stratigraphy here {in the nearby bog] links with the former lake.”

Another caption reads, “We look forward to the analyses of the cores…”

My Post-September 6 Dig Questions Answered

In answer to other questions in my e-mail, Dr. Brush said that the large bone, about 3- by 6-inches, might be part of the mastodon’s jaw bone, based on the bone’s angle, “but we haven’t been able to verify that yet.”

He also said that the charcoal found where we were digging could have “come from an earlier land clearance by one of the farmers who previously owned this property (i.e. cutting down trees near the bog and burning them).  There is always the possibility that the charcoal might also be from Native American campsites.  However, since we are still digging in disturbed soil from the recent ditch digging activities, as well as plowing, it’s impossible to say at this point.”

Big Bones Soon

The action continues this upcoming weekend.  On Saturday, a small team will dig down to the drainage pipe to find clues as to where we should concentrate our excavation work on Sunday.   The big bones should start showing up soon!