There are three main types of mountains: volcanic, fold, and block. Movements of tectonic plates create volcanoes along the plate boundaries, which erupt and form mountains. A volcanic arc system is a series of volcanoes that form near a subduction zone where the crust of a sinking oceanic plate melts. Most volcanoes occur in a band encircling the Pacific Ocean the Pacific Ring of Fire , and in another that extends from the Mediterranean across Asia to join the Pacific band in the Indonesian Archipelago.
The most important types of volcanic mountain are composite cones or stratovolcanoes Vesuvius, Kilimanjaro and Mount Fuji are examples and shield volcanoes such as Mauna Loa on Hawaii, a hotspot volcano.
A shield volcano has a gently sloping cone due to the low viscosity of the emitted material, primarily basalt. The relation between slope and viscosity falls under the topic of angle of repose.
Stratovolcanoes associated with a subduction left and a spreading ridge volcano right. A hotspot volcano is center. When plates collide or undergo subduction that is — ride one over another , the plates tend to buckle and fold, forming mountains.
Most of the major continental mountain ranges are associated with thrusting and folding or orogenesis. Examples are the Jura and the Zagros mountains. Two processes creating mountains: Top:delamination by intrusion of hot asthenosphere; Bottom: Subduction of ocean crust. Fault-block mountain of tilted type.
When a fault block is raised or tilted, block mountains can result. A spreading apart of the surface causes tensional forces. When the tensional forces are strong enough to cause a plate to split apart, it does so such that a center block drops down relative to its flanking blocks.
An example is the Sierra Nevada Range, where delamination created a block km long and 80 km wide that consists of many individual portions tipped gently west, with east facing slips rising abruptly to produce the highest mountain front in the continental United States. The Mountain Environment by Mandy Barrow. Mountains are formed by slow but gigantic movements of the earth's crust the outer layer of the Earth. The Earth's crust is made up of 6 huge slabs called plates, which fit together like a jigsaw puzzle.
When two slabs of the earth's crust smash into each other the land can be pushed upwards, forming mountains. Many of the greatest mountain ranges of the world have formed because of enormous collisions between continents. Sometimes the crust has folded and buckled, sometimes it breaks into huge blocks. In both cases, great areas of land are lifted upwards to form mountains.
Other mountains are formed by the earth's crust rising into a dome, or by volcanic activity when the crust cracks open. What different types of Mountains are there? Fold Mountains. Fold mountains are the most common type of mountain. These ranges were formed over millions of years. Fold mountains are formed when two plates collide head on, and their edges crumbled, much the same way as a piece of paper folds when pushed together.
Most of them were able to guess that it was becoming a mountain. They took turn moving the boxes towards each other and saw that the outcome was always the same, though sometimes a slightly different shape was formed.
Our kids have seen the Rockies as we drive through them nearly every year, so they were able to easily picture what those mountains look like. If your children or students are not as familiar with fold mountains, I would suggest showing them some images of what fold mountains look like. If you are looking for other ways to make science come alive for kids, you will want to check out our Simple Science board on Pinterest or check out some of our other science experiments.
Layers of the Earth Science Experiment. Earthquake Experiment. Liquified rock is called magma when it is within the earth and lava when it flows onto the earth's surface or is blown into the air.
Ash and cinders ejected during an eruption of a volcano are called pyroclastics. The interlayering of lava and pyroclastics around a vent forms the cone we call a volcano. Volcanoes range in size from small cones several hundred feet in diameter and a hundred or so feet high to gigantic features like the Hawaiian Islands.
Locations mentioned are shown in Figure 6. While there are no volcanoes in West Virginia today, they may have been present in the western part of the State more that million years ago.
Ash deposits from ancient volcanoes to the east are found in the State. Fault-block mountains are formed by the movement of large crustal blocks along faults formed when tensional forces pull apart the crust Figure 3. Tension is often the result of uplifting part of the crust; it can also be produced by opposite-flowing convection cells in the mantle see Figure 1. Fault-block mountains are present in the Great Basin of the southwestern United States.
They may have been present in the western and central parts of West Virginia about million years ago. Complex mountains are formed when the crust is subjected to very large compressive forces Figure 4. Under large compressive forces and moderately high temperatures and pressures, parts of the crust are bent into large folds and broken into slices that slide over underlying rocks.
The slices of the rock slide away from the source of compression. Such complex mountains are present in West Virginia's eastern panhandle. In those parts of complex mountains where the crust is subjected to large compressive forces and very high temperatures and pressures, the original rocks change to metamorphic rocks.
Also, igneous rocks formed from magma may be injected into the complex mountains. The Appalachian Mountains, the Alps, and the Himalayas are examples of complex mountains formed in this manner.
Erosional mountains are formed by erosion of uplifts like the Black Hills in western South Dakota and extensive plateaus like the Appalachian Plateau in the eastern United States which includes western West Virginia. In both of these areas, rivers have carved complex systems of hills and mountains in the uplifted rocks Figure 5.
Location of Mountains To understand why mountains occur where they do, we must first understand continental drift, sea-floor spreading, and plate tectonics. During the 19th century, people began to speculate about the "fit" of the eastern coastlines of the Americas with the western coastlines of Africa, Europe, and Greenland Figure 6. In time, it was suggested that continents might break apart and drift about the surface of the earth. Around World War I, the German meteorologist and geophysicist Alfred Wegener proposed a theory of continental drift, including a mechanism to explain how continents move.
Many geologists working in the southern hemisphere accepted this theory of continental drift, or a modification of it, because it explained many geological features in the southern hemisphere that were otherwise unexplainable.
However, many geologists working in the northern hemisphere rejected the theory, in part because the earth's crust is not strong enough to do some of the things required by the theory. For example, one proposed mechanism required continents to plow through the mantle like ships through the seas.
The crust is not strong enough to do that. Other mechanisms were advanced to meet these objections, but for various reasons they too were rejected by many geologists. Since World War II, mapping of the ocean floor has revealed that all oceans contain at least one set of parallel ridges separated by a rift valley, collectively called a mid-ocean ridge see Figure 7.
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