what plate is the sierra nevada mountains on
Sierra Nevada (U.S.) In the Cretaceous, a subduction zone formed at the edge of the continent.[20] This means that an oceanic plate started to dive beneath the North American plate. Magma formed through the subduction of the ancient Farallon Plate rose in plumes (plutons) deep underground, their combined mass forming what is called the Sierra Nevada batholith. These plutons formed at various times, from 115 Ma to 87 Ma.[21] The earlier plutons formed in the western half of the Sierra, while the later plutons formed in the eastern half of the Sierra.[18] By 66 Ma, the proto-Sierra Nevada had been worn down to a range of rolling low mountains, a few thousand feet high.
Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwestâ€“southeast through Northwestern and Western Mexico, and along the Gulf of California. The Sierra Madre is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica.