24. Amabel formation dolostone

Amabel dolostone, sedimentary rock, from Wiarton, Ontario. Paleozoic, Silurian 400 million years old. The amabel dolostone forms the caprock of the Niagara Escarpment. This rock is quarried for building stone, crushed stone, flux stone and dolomitic lime products. Stone from the Adair Marble Quarries was used to build the new Canadian embassy in Washington, District of Columbia (D.C.), U.S.A.

This rock formed in a warm, salt sea in the area known as the Michigan Basin. Limestone is formed by the accumulation of the skeletons and shells of small sea life. This material was changed by dolomitization. Magnesium is added to the limestone causing it to recrystalise. This destroys the microscopic fossils and makes the larger ones difficult to identify. Holes are also formed during this process. These holes sometimes fill with other minerals. In the Wiarton area these holes, known as vugs, fill with sphalerite (zinc sulphide) and other minerals.

Location of Wiarton in Ontario
Close up of the Amadel Dolostone