Range Mountains of Newfoundland. Other exposures include the Shenandoah and French Broad massifs, which comprise the Blue Ridge province of Virginia. Blue Ridge rocks consist of various gneisses of upper amphibolite and granulite facies, intruded by charnockites and granitoid rocks. These igneous rocks were intruded in three intervals: c. 1160–1140 Ma, c. 1112 Ma, and c. 1080–1050 Ma, and are massive to weakly foliated in texture. Adirondacks This region consists of a massive dome of Proterozoic rock on the New York-Canada border. Both the Elzevirian (c. 1250–1190 Ma) and Ottawan (c. 1080–1020 Ma) orogenic pulses are recorded in the Adirondacks, producing high-grade metamorphic rock. A northwest-trending high-strain shear zone separates the dome into the Highlands to the southeast and the Lowlands to the northwest. It is believed that the shear zone (the Carthage-Colton) was a transpressional boundary during the Ottawan, when the Highlands were thrust over the Lowlands. Grenville province The Grenville province is named for the village of Grenville in Quebec, and constitutes the youngest portion of the Canadian Shield. Since the area has not undergone any regional metamorphic overprinting since the orogeny, it is considered an ideal study area for Grenville and pre-Grenville age tectonics. Hence, most of what is known about the orogeny and its processes is derived from the Grenville Province. See also Adirondack Mountains in New York State Blue Ridge Mountains in Appalachia Laurentian Mountains in Quebec Llano Uplift in Central Texas Supercontinent cycle References External links The Grenville The Crustal Structure of The Grenville Front Himalayan-type syntaxis in the Grenville orogen Tectonic evolution of the southern Laurentian Grenville orogen THE FIRST SUPERCONTINENT Metamorphism of the Grenville Orogeny Orogenies of North America Neoproterozoic orogenies Mesoproterozoic orogenies Proterozoic North America Precambrian United States