Slide Mountain Ocean
Plate tectonics of the Intermontane Islands arc 195 million years ago
The Slide Mountain Ocean was an ancient ocean that existed between the Intermontane Islands and North America in the Triassic time beginning around 245 million years ago. Its name comes from the Slide Mountain Terrane, a region made of rocks from the floor of the ancient ocean. There was a subduction zone on the Slide Mountain Ocean's floor called the Intermontane Trench where the Intermontane Plate was being subducted under North America. The floor of the Slide Mountain Ocean was pushed up onto the ancient margin of North America.