Earth & Space Science
Students examine the different motions of lithospheric plates and discover how the Himalayas were formed.
After completing this tutorial, you will be able to complete the following:
The Earth's interior is frequently divided into crust, mantle, and core, based on compositional differences between these layers. Another method of describing the Earth's outer layers depends on the structural properties of the layers. With this approach, the outermost part of the Earth is rigid and brittle. This layer is called the lithosphere, and it consists of the crust and the uppermost part of the mantle.
Below the lithosphere is a relatively soft layer called the asthenosphere. Although the asthenosphere is still mostly solid, it is capable of flowing slowly through internal deformation. The theory of plate tectonics states that the Earth's lithosphere is broken into large, rigid pieces called plates, which float and move on the underlying asthenosphere. Most major geologic features on the Earth, such as fold mountain belts, ocean trenches, volcanic arcs, and rift valleys, are the result of movements of the plates near the Earth's surface.
The lithosphere, which underlies the Earth's ocean basins, contains a crust that is relatively thin (approximately 7-10 km) and fairly dense, allowing oceanic lithosphere to sink into the asthenosphere without much difficulty. Thus, as long as at least one of the plates at a convergent plate boundary comprises oceanic lithosphere, subduction will occur.
|Approximate Time||20 Minutes|
|Pre-requisite Concepts||Students should be familiar with volcanoes, faults, earthquakes, and mountain belts.|
|Course||Earth & Space Science|
|Type of Tutorial||Concept Development|
|Key Vocabulary||3-D, Aleutian, Alps|