Lawrence Platform occupies the lowlands where much of Quebec's urban population lives, while the Gaspe Peninsula, Anticosti Island and the Magdalene Islands are part of the Appalachian Province. Paleozoic (539-251 million years ago) During the Taconic orogeny that began the formation of the Appalachian Mountains, amphibolite, mica schist and other metamorphic rocks formed a belt running down the Gaspe Peninsula to Sherbrooke. Muscovite bearing granites and metamorphic rocks around Asbestos formed over a broad span from 468 to 379 million years ago. While slate and plutonic tonalite formed in the vicinity of Becancour and Quebec City respectively. Around 292 million years ago, volcanism deposited tuff in the Magdalene Islands. Mesozoic (251-66 million years ago) Sedimentary deposition and some volcanic activity took place during the Mesozoic, particularly in the lowlands of the St. Lawrence Platform. Central Montreal is underlain by 119 to 117 million year old plutonic basanite, lamprophyre and camptonite while to the immediate southeast amphibole gabbro and peralkaline rocks formed from 141 to 123 million years ago. Cretaceous intrusive rocks formed hills housed in the sedimentary rocks of the St. Lawrence Lowlands Platform, notably Mount St. Bruno. Cenozoic (66 million years ago-present) Quebec experienced intense erosion during the past 2.5 million years of the Quaternary, which often mobilized older rocks, such as Proterozoic granite boulders found offshore in the moraines which formed parts of the Magdalene Islands. Some of the youngest rocks in Quebec are situated along the western border with Ontario, including the Bedford Hill Rhyolite and dacites which are less than one million years old. References