Bob Hunter Memorial Park in Rouge Park
Site Interpretive Panels – copy
Meet nature’s great bulldozer – the glacier
Imagine this site buried under a sheet of ice 1km thick. Great forces have sculpted the
undulating landscape of Bob Hunter Memorial Park. During the last ice age, lobes of great ice
sheets advanced and retreated across the southern Ontario landscape several times, scouring
out the Great Lakes and leaving behind the debris carried south from the Canadian Shield.
About 13,000 years ago, a small gap opened between the lobe covering Lake Ontario and the
main sheet to the north. As melt water poured through this gap on its way south, the sands and
gravel it dropped formed the Oak Ridges Moraine. Then as the Lake Ontario lobe fanned out, it
carved great grooves running from the southeast to the northwest across what has now
become the Greater Toronto Area. One of these grooves later formed the valley of the Rouge
River. Bob Hunter Memorial Park lies in the midst of the Peel Plain, an undulating tract of clay
soils which overlies a thick layer of glacial till, clay particles and broken shale and limestone.
A souvenir of the ice age
During the last ice age, great chunks of granite, basalt and other ancient rock were broken from
the Canadian Shield and dragged south by the glaciers. Polished smooth during their travels,
these “erratics” range in size from small pebbles to large boulders and are scattered throughout
Bob Hunter Park. Geologists can track the paths of the glaciers by tracing the distinctive
mineral make-up of erratics back to their parent bedrock.