Within a few kilometers of the Manor Park Elementary School, one can see many interesting examples of the geological development of this region of Canada. According to an article (2004) from W.K. Fyson, a professor of geology at the University of Ottawa and a long-term resident of Manor Park, he had described the geological makeup of the Manor Park community and explanations of these geological formations.
Two groups of sedimentary deposits are present in our region: (1) sediments which were laid down in a shallow sea some 450 million years ago, and which have since been consolidated to form bedrock; (2) unconsolidated sediments which were deposited on the bedrock roughly 1.8 million years ago.
Within a broad region that encompasses Ottawa, the Precambrian rocks are older than 1 billion years. Included are granites and similar igneous or intrusive rocks that crystallized and solidified from a molten state. Also included are sedimentary and other rocks which, when deep in the crust, were transformed by high temperatures and pressure into minerals such as mica.
Shales and fine-grained sandstones of the Rockcliffe formation are best exposed in cliffs along escarpments. Many of the sandstones contain, in addition to quartz grains, mica flakes that provide surfaces of parting parallel to the layering. The sandstones are thus readily split and have been used as flag stones for garden paths in Manor Park.
Limestones with thinner beds of shale predominate throughout the Ottawa group. The limestones are partly exposed along escarpments. Near Manor Park they are best seen in road-side cuts and quarry walls.
Fossils clearly displayed only in the Langs Road quarry include stromatolites, which are curved laminations in the limestone, believed to be of calcareous algal origin. Stromatolites are also present in Precambrian limestones, many examples being older than 2 billion years. They are the most readily recognizable evidence for early life on earth.
During the last maximum glaciation, the Laurentide ice sheet extended from the New England coastline to the Great Lakes. In the Ottawa region, the ice was probably over 2,000 metres thick, its great weight depressing the bedrock at least 200 metres. Consequently, the till resisted erosion and occupies high ground, for example in Rockcliffe and the Beechwood Cemetery.
After the glacial retreat and the removal of the ice overburden, the crustal rebound and uplift slowed down. As a result, the Ottawa valley remained depressed at least 200 metres, which was below sea level, and about 12,000 years ago it was inundated by the Champlain Sea.
Clays were deposited offshore away from the beaches fringing the inland sea. Glacial movement and streams brought coarse to fine-grained material to the shoreline, where waves reworked the debris, principally ground-up rock flour, carried in suspension offshore, then slowly deposited to form a clay locally known as Leda clay, which underlies most of Manor Park.
Perhaps the most interesting fossils in the Leda clay are whale bones that have been recovered from up the Ottawa valley as far as Pembroke. A whale bone from a depth of 91 metres in the clay near the Ottawa airport was determined to be about 10,500 years old. Evidently, at this time before the end of clay deposition, the sea was deep enough and had enough food for whales.
As glaciers retreated and as the overburden of ice diminished, the Ottawa valley rose towards and above sea level, and the Champlain Sea was replaced by fresh water. Large volumes of fresh water from rapid melting of the ice flowed down a swollen Ottawa River, which in the north and west drained lakes much larger than the subsequent Great Lakes.
Mer Bleue, southeast of Blackburn Hamlet, is the most extensive modern marshland in the Ottawa area. The organic material found at depths of about 70 metres at two sites within the marsh is about 7,600 and 6,700 years old.
