Click here to skip to the content

Glacier Rock Transcript


Dr. Randall Miller, Research Curator, Geology and Palaeontology, New Brunswick Museum

Glacial erratics are rocks, sometimes very large boulders that seem out of place. They have been dropped on the land by melting glaciers.

Glacier Rock located at McAdam Heritage Park in the Village of McAdam is a two-meter-high granite erratic, a remnant of the last ice age. Originally located just north of the village, this very unusual boulder was discovered sitting among hundreds of gray granite boulders and has come to represent and symbolize the geological history of the area around McAdam.

The boulder has rare spherical patterns that have occasionally been seen in other granite bodies  in other parts of the world. The circular features known as ‘orbicules’ began their formation some 400 million years ago when molten material from the "Pokiok" granite body intruded into the overlying sedimentary bedrock. Molten material came in contact with water in the crust that probably caused it to ‘gel’ and coat the sedimentary fragments with a rim of molten granite. The molten rim eventually cooled around the sedimentary core.