In this image, the purple, Star Peak basin is where the West Nevada Triassic basin sediments were deposited in the back arc environment following development of the early Andean-style continental magmatic arc. The green-gray rocks are the arc volcanics along the edge of NA. South of the Canadian border, the rocks are all forming in situ, but north of the border, island arcs continue to collide with western British Colombia through the Jurassic and Cretaceous. Localities that have a ‘t’ next to them have oceanic sediments of Tethyan origin, indicating Asiatic origin. The ‘bs’ signifies the location of high pressure and low temperature metamorphic rocks characteristic of a subduction environment. (Courtesy of Prof. Burchfiel.)