Basic Newfoundland Rock Story
Geological Subdivisions of Newfoundland
The bringing together of ancient oceans and continents has given Newfoundland three geological zones: the Western, Central and Eastern zones. Each of these zones has distinct rock types and geological histories.
Rocks (Base and Precious Minerals) on the Island of Newfoundland are of Geologic and Economic importance. The Western Zone has been part of North America for at least the last billion years (1000 million), but the other two zones are relative newcomers.
Note: It has been suggested by prominent Geologist / Geo-Scientist that the Central and Western Zones have a direct correlation and possibly a stronger rock connection that has been suggested.
About 600 million years ago, North America was part of a much larger continent. Then this continent broke apart. A mid-ocean ridge developed along the break and the Iapetus Ocean began to open. By the Middle Cambrian (540 million years ago), the Western Zone lay on the eastern edge of ancient North America, a continent we now call Laurentia.
Newfoundland in the Middle Cambrian
Opening of the Iapetus Ocean and the formation of a mid-ocean ridge 540 million years ago during the Middle Cambrian period. What occurred next was the convection currents shifted and subduction began. By Early Ordovician time (about 490 million years ago), volcanic island arcs had grown above the subduction zones, as the floor of the Iapetus Ocean sank back into the mantle. Today, the remains of these island arcs are preserved in the volcanic and intrusive rocks of the Central Zone.