Shapes of Dawn
The Mt. Rainier stratovolcano rises to an elevation of 14410 ft (4392 m). The mountain is young as it exists for less than a million years although first volcanic activity in the Cascade Range already begun 40 million years ago. At that time the area was a shallow sea. The colliding plates lifted the young range above the sea level. Repeated lava flows and explosive volcanism piled up numerous rock layers. Additionally, large volumes of upwelling magma solidified underground forming a large pluton of coarse-grained granodiorite 12 million years ago. Erosion of the overlying mountains unroofed the pluton. The area glaciated in the Pleistocene Epoch while young Mt. Rainier began to form as a low and broad volcano on top of the mountainous terrain. Numerous eruptions lifted the volcano to lofty 16.000 ft (4900 m) 75.000 years ago. One third of the mountains volume was eroded by glaciers. 6000 years ago, violent eruptions blasted away the eastern part of the mountain and the summit leaving a caldera that filled with ice. 2500 years ago the volcano reconstructed its summit with a new cone. The last minor ash eruption was in 1850.
August 2008
Canon 20D, Canon 10-22mm, f/16, 1 sec, ISO 100, tripod