Geologic Time
Earth's Interior and Plate Tectonics
The earth's interior has several layers and still has an affect on the North Cascades. Starting with the inner most layer and working out, the order is: The inner core, the outer core, the mantle, then the crust. The way in which this park is affected by the earth's structure starts with the crust. Inside the crust there are two very important layers, the lithosphere and asthenosphere. The lithosphere consists of tectonic plates that are always in motion. These plates that are constantly moving, float on the asthenosphere, a layer that is made up of a semi liquid. Also when these plates meet another plate they form a plate boundary. There are three kinds of plate boundaries. Convergent boundaries cause mountains and volcanoes because they collide. Transform boundaries occur when plates are grinding past each other and this causes earthquakes. Finally, divergent boundaries happen when tectonic plates are moving past each other; A rift valley forms.
Formation
The creation of North Cascades National Park took millions of years. It all began when the Pacific Plate hit the San Andreas fault. This changed the land significantly and also caused the formation of mountains. These mountains are still changing today and getting taller because the two plates are still colliding. Over geologic time things like erosion, weathering, deposition, and glaciers have changed the park as well.