This image shows where a drill was reportedly used to destroy carvings that were once on the Glenwood Erratic.

Aboriginal Petroglyphs Destroyed By Vandals Armed With Acid and a Drill

A rock drill, acid and a power washer; it’s not the beginning of a joke about a hardware store—it’s what was used by cultural vandals to destroy aboriginal pictograms and petroglyphs on a boulder in Alberta, Canada.

The damage was discovered when historian Stan Knowlton, Piikani First Nation, went to photograph and test the markings on the Glenwood Erratic near Pincher Creek in southern Alberta on September 9.

“It seems a little coincidental that the night before I was planning to go in with a high definition camera to record the markings, someone in a truck brings in a generator or compressor, a large hammer drill, maybe lights and a ladder and decimates the very thing I was hoping to preserve,” Knowlton said a report, titled “Desecration of Glenwood Erratic,” which the Pincher Creek Voice published with its story.

Knowlton pointed out in his report that this is just the latest in a string of vandalized pictogram and petroglyph sites in Alberta and thinks someone is out to destroy evidence that could prove the Blackfoot First Nations had a written language before European migration.

“I suspect the link to this destruction is to nullify my long held claim that the Blackfoot had a written language before missionaries arrived, which could force archeologists to rewrite history,” Knowlton wrote in his report.

The writings on the erratic—a rock that differs in size and shape from the rock surrounding it, having been transported from its place of origin by glacial action—were highlighted and preserved using red ochre.

“Blackfoot/Cree Blackfoot is the older version of syllabic writing,” he told the Pincher Creek Voice. “This glacial erratic was dropped here about 10,000 years ago. It’s hard to date the writings. It would have been possible to carbon date the oils in the red ochre.” With the ochre washed away, Knowlton may not be able to date it at all.

Knowlton said the use of the red ochre is what tipped him off that the rock had at one time been a sacred site for ceremonies. He explained to the National Post how about five years ago he oversaw tobacco ceremonies and other rites to prepare for his thorough examination of the symbols in a culturally sensitive way.

When the lichen covering the symbols on the top of the erratic started to come off after summer, Knowlton knew that it was time to start his examination.

But when he climbed his ladder to scale the 16-foot vertical rock, the subject of his study had been wiped away in the night.

Glenwood Erratic Discoloration

The dark discoloration spots show where petroglyphs and pictograms were reportedly destroyed by vandals. (Chris Davis/Pincher Creek Voice)

“To my absolute horror, I could see what kind of damage had been done,” he told the National Post. “I just couldn’t believe it.”

The vandals used a truck to get to the rock—Knowlton saw the tire tracks as he arrived on September 9—and he suspects they used a power washer to remove the lichen covering the symbols before spraying acid on the paintings and drilling away the carvings with a rock bore or hammer drill.

“We have been violated, future generations have been robbed and the world has been deprived of the ancient knowledge contained within these artifacts,” Knowlton wrote in his report. “This urgent matter must follow a formal plan of action at all levels.”

Knowlton said in his report that very few people knew there was writing on the top of the erratic since the lichen covering it was so thick.

“Unfortunately, the culprit’s drill bit has now reduced the artifacts to dust. What the wind and rain could not wash or blow away is now a painful memory,” Knowlton said in his report. “The objective was total destruction and as the culprit had to carry a large hammer drill up a 16-foot ladder at night, this was a deliberate act to erase history and definitely not accidental.”

Related article:

Alberta Mounties Will Investigate Aboriginal Petroglyph Damage

To give you an idea of how tall the Glenwood Erratic is, here's an image taken before the damage was done in December 2010 from


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Aboriginal Petroglyphs Destroyed By Vandals Armed With Acid and a Drill