Stones of Canada Ep 4: Limestone’s of Canada

Stones of Canada Ep 4: Limestone’s of Canada

Venu Gopal

Sedimentary rock - Limestone

 Limestone is a SEDIMENTARY ROCK largely or wholly composed of calcium carbonate (CaCO3). Carbonate rocks, and in some cases marble, the metamorphosed near-equivalent of limestone, are important to the construction industry as building stone and aggregate, and as the primary component of Portland CEMENT and lime.

(Limestone Barrens of Newfoundland, Canada)

Limestone is quarried in the Northwest Territories, British Columbia, Alberta, Manitoba, Ontario, Nova Scotia, and Newfoundland. Lime plants have been established near industrial centers where reserves of suitable limestone are available and where major consumers are situated. 

Ontario and Québec produce over 70% of Canada's total lime. About 3% of all stone quarried in Canada is used as dimension stone or ornamental building stone. Most prominent are the granites of Québec and the limestones of Ontario, Québec, and Manitoba. Perhaps the best known of the latter is Manitoba Tyndall Stone, an attractively mottled dolomitic limestone quarried near Winnipeg.

Tyndall stone

It is the national building stone of Canada. It is a form of mottled cream-colored limestone. Tyndall is quarried near Garson, Manitoba which is about 45 kilometers from central Winnipeg. This stone is typical of the visible presence of fossilized nautiluses, trilobites, coral, and other ancient animal life. 

(Tyndall Stone - Limestone of Canada)

Tyndall stone’s historical character is also attributable to its deep historical roots in the famous Manitoba construction. The stone has been a common building material in the province’s architecture since the earliest days of European settlement. The lower fort Garry of 1832 is one of the first examples of its usage. In recent years  Tyndall stones found its home on tall apartment blocks, schools, and office buildings. At the same time, the use of this unique stone has found popularity beyond Manitoba that are the Canadian parliament buildings in Ottawa and the Canadian Museum of Civilization in Quebec. Tyndall stone is a registered trademark name by Gillis Quarries Limited. It is the dolomitic limestone that is quarried from the Selkirk member of the Ordovician red river formation of Manitoba Canada. This stone has a pervasive mottling of darker dolomite that gives the rock a tapestry-like effect. This makes this stone popular as a building and ornamental stone. This stone quarry is operated by Gillis Quarry Ltd that has owned the quarry since 1910. 

The most striking thing about this stone is its decorative feature. They look like they are riddled with thalassinoides trace fossils. These are branching burrows with T or Y-shaped junctions made by creatures tunneling through the soft sediments. The following are examples of natural fossil designs. 

Thalassinoids burrows a wall cladding on the Terminal City Club Vancouver, weathered thalassinoides burrows at the Fairmont Banff Springs Hotel, Fisheries burrows at the Terminal City Club Vancouver, large orthoceras  sections on book-matched slabs at the Fairmont Chateau lake Louis, Orthoceras on the terrace of the Fairmont Banff Springs hotel, Rugose coral on the Terminal City Club Vancouver, a fragment of stromatoporoid at the Fairmont Chateau lake Louis 

The Gillis Quarry Story of Tyndall stone

The Gillis Quarry Ltd., on its web page, narrates the story of the formation…… 

450 million years ago it was the Palaeozoic era and the age of Pangea. Southern Manitoba was part of the warm shallow inland sea located south of the equator. Organisms such as corals, sponges, Gastropods, trilobites, and algae burrowed through the bottom of a soft Limey, muddy sea, seeking food and refuge from predators; traces of their passage left behind. 

The more tightly packed surrounding sediments, primarily calcium carbonate, lithified first, leaving the many burrows untouched. Later magnesium-rich water percolated through the rock depositing dolomite in the burrows, but it could not penetrate the tightly cemented limestone. 

It is the preserved, complexed branches of burrows or trace fossils of these magical sea creatures that created Tyndall stone's beautiful markings which gives Tyndall stones their unique appearance.

Canada is the only source in the world for this stone, geologically referred to as the upper bottled limestone of the red river formation of the Ordovician system.