The Appalachian Mountains are a mountain range along the east coast of the North American continent stretching from Alabama to Newfoundland. Due to continental drift, there are even Appalachian-like geological formations in northwestern Europe and Africa. Plate tectonics led to the creation of the Appalachian Mountains about 500 to 420 million years ago (Ma) BC. During the closure of the Iapetus Ocean, several episodes of volcanism formed volcanic rocks such as volcanic tuffs and basalts. At the same time, sedimentary rocks (sandstone, limestone, mud rock and shale) were formed at the bottom of the Iapetus Ocean on the continental margin. All of this geological material was compressed, folded, and carted to form the Appalachian Mountains. Some sedimentary rocks show very little metamorphism, while others, of deeper origin, show green-shale metamorphism. 

In the Appalachian Mountains, from the southern Eastern Townships to the Gaspé Peninsula, we find ophiolites. Ophiolite is a complex of volcanic and magmatic rocks, some of which are serpentinized and originate from a fragment of the bottom of the ancient Iapetus Ocean (oceanic crust). Several minerals have been mined in the Appalachian Mountains, including chrysotile and chromite, which are associated with ophiolites, as well as copper, zinc, lead, silver, and gold which are associated with volcanic rocks.