Mount St. Helens, How It Was Formed, Plains, Pleat us, And Three Different Types Of Mountains Mount St. Helens stands on eroded remains of an earlier volcano active between 2, 500 and 40, 000 years ago. The upper part of the cone was built around 400 years ago. Mount St. Helens is composed of lava flows and fragmented material consisting of debris.
A cross-section would show alternating layers of lava, ash, and rock debris. Lava Caves form when a crust develops on the surface of fresh streams of lava. When the lava flow stops the molten drains away leaving hollow caves. Many faces including the Ape Cave were formed this way. Mount St. Helens was active until 1857.
Eyewitness accounts have recorded that the volcano was very active in the 1830 s and 1840 s. We do not know if this can be linked with the 1980 eruption. Information from web Plains: A land form that is a large relatively flat area. Characteristics of Plains: -Endless flat fields of grass.
-Many are used for farming. -Cows also graze on plains. -The Plains found near oceans are Coastal Plains. -The Plains found everywhere else are known as Interior Plains. -Plains makeup one-half of the U. S.
Coastal Plains: Broad areas along the oceans shore. Characteristics of Coastal Plains: -Costal Plains are often called lowlands. -Atlantic Coastal Plains go up the East coast and contain low rolling hills, swamps, and marsh. Interior Plains: -Extend from the Appalachian Mountains, to the Rocky Mountains, then to the Appalachian Mountains -Contain rolling hills and the Central Lowlands.
The Essay on Mount St Helen Topinka Page
Mount St. Helen is a volcano located along the Cascade range which is a volcano chain stretching from Northern California to British Colombia. It now stands at a height of 8, 364 feet above sea level. Mount St. Helen was on of the smaller eruptions of five major ones in Washington State. Its elevation before the eruption was 9, 677 feet high. On March 29, 1980 after a period of one-hundred and ...
-Large portions of the Interior Plains are known as the Great Plains. -Theyre flat, grassy, dry, and have few trees. -The Interior Plains are also referred to as High Plains. Plateaus: Landforms create next to mountains, when forces with in Earth raised high, relatively flat areas of nearly horizontal rocks. Characteristics of Plateaus: -Plateaus rise steeply from the land around them. The Colorado Plateau: -The Colorado Plateau lies west of the Rocky Mountains.
-It has only a few permanent rivers due to the plateaus dryness. -The Colorado Plateau has a desert landscape. -The Colorado River cut into the plateau and created the Grand Canyon. Fault Block Mountains: Jagged Mountains formed from huge tilted blocks of rock that are separated from surrounding rock by faults. The Grand Tetons: -When the Grand Tetons formed one block was tilted and pushed up.
The other block pushed down. -Landscape includes sharp jagged peaks. Volcanic Mountains: Created when magma with in Earth Escapes to the surface, building cones of lava and ash. Mauna Loa in Hawaii: -The Hawaiian Islands are peaks of huge volcanoes that stick out of the Pacific Ocean. Up warped Mountains: Mountains formed when Earths crust is pushed up and eroded forming sharp peaks and ridges. The Rocky Mountains: -The Rocky Mountains sedimentary rock on top of crust eroded leaving behind igneous and metamorphic rock underneath.
-Igneous and Metamorphic rocks eroded and formed sharp peaks. Anticlines: Folds that have the oldest rock in the core or middle, and the youngest rocks on the outside layers. Sync lines: Folds that have the youngest rock layers on the inside and the oldest rock layers on the outside.
