Billion Year Old Boulder Calls Ashland University Home

Billion Year Old Boulder Calls Ashland University Home

  • 10/19/2018 7:24:59 PM
  • Jenna Ramolt
  • Local News

ASHLAND, OH – A billion-year-old boulder has found its home on campus at Ashland University, where a plaque has been placed to honor its historic significance.

The boulder was uncovered in 2017 by the Kinder Morgan Company during construction of the Utopia East Pipeline. A neighborhood man found the boulder on the Keener family property and reported his finding to the State Historic Preservation Office in Columbus. Since then, several historians and curators have been contacted in reference to the boulder, but Ashland University was given the opportunity to display it thanks to the campus’s proximity to the location of the discovery.

According to Dr. William Reinthal, an adjunct faculty member in Geology at Ashland University, the boulder is over a billion years old. The igneous boulder was formed deep underground on the Precambrian Shield in Canada, probably near the base of an ancient volcanic mountain range. Dr. Reinthal says it went through quite the journey to get to Ashland, Ohio.

“This rock, quite literally, speaks of the Earth, and deep time,” Reinthal said. “The oldest, black portion of this boulder is a mafic-rich, hornblende-biotite, quartz monzonitic. This rock was later subjected to compressional stresses that yielded a characteristic 60/120 degree set of joint fractures that were often terminated, perpendicular to the angular intersections, by horizontal fractures. This produced a repeating trapezoidal pattern.”

At some point a pink granitic magma came into contact with the black quartz monzonite and flowed into those joint fractures, aiding in the creation of the unique shapes and colors on the boulder.

What finally brought the boulder to Ohio is likely the same source that carried a lot of rock, sediment, and debris across large land masses: the glaciers.

Dr. Nigel Brush, professor of Geology at AU, explained, “Some of these rock fragments, including this boulder, became embedded in a Canadian glacier during the Ice Age and were carried south into Ohio where they were deposited as glacial till when the ice sheet melted. The boulder may have been deposited in this manner during the most recent glacial stage – the Wisconsin, some 70,000 to 100,000 years ago. Notice the large, shallow, polished glacial groove running from left to right across the front of this boulder.”

Finally, buried in a glacial till deposit near Nankin, erosion wore away at the mafic minerals in the older quartz monzonite in this boulder faster than it did the felsic minerals in the younger granite, resulting in the final unique appearance of this piece of natural history.

“Ashland University would like to thank the family of John Keener for donating this boulder, Kinder Morgan for loading the boulder and Simonson Construction Services for providing a truck to transport the boulder to campus and a large forklift for unloading the boulder,” Dr. Brush said.

 

Ashland University officials have installed a plaque in front of a boulder that has found a new home on the east side of the Arthur and Maxine Sheets Rybolt Greenhouse on the AU campus. A ceremony to recognize the boulder and plaque will be held on Oct. 31 at 1 p.m. 

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