the north american cascade mountains are an example of pre - tertiary rocks.
the north american cascade mountains are an example of pre - tertiary rocks.
of what are the north american cascade mountains an example?
pre - tertiary rocks
the north cascades feature some of the most rugged topography in the cascade range with craggy peaks, ridges, and deep glacial valleys. geological events occurring many years ago created the diverse topography and drastic elevation changes over the cascade range leading to the various climate differences. the history of the formation of the cascade mountains dates back millions of years ago to the late eocene epoch. with the north american plate overriding the pacific plate, episodes of volcanic igneous activity persisted. in addition, small fragments of the oceanic and continental lithosphere called terranes created the north cascades about 50 million years ago.
copper benchmark
the canadian cascade arc, also called the canadian cascades, is the canadian segment of the north american cascade volcanic arc. located entirely within the canadian province of british columbia, it extends from the cascade mountains in the south to the coast mountains in the north. specifically, the southern end of the canadian cascades begin at the canada–united states border. however, the specific boundaries of the northern end are not precisely known and the geology in this part of the volcanic arc is poorly understood. it is widely accepted by geologists that the canadian cascade arc extends through the pacific ranges of the coast mountains. however, others have expressed concern that the volcanic arc possibly extends further north into the kitimat ranges, another subdivision of the coast mountains, and even as far north as haida gwaii (formerly known as the queen charlotte islands).
canadian cascade arc