| The Earth is composed of a number of shells: atmosphere, hydrosphere, biosphere, lithosphere, asthenosphere, mesosphere, liquid core and solid core. Through the interaction between plate tectonic processes and deep mantle dynamic, these shells interact with each other. For example, cold (therefore dense) lithospheric material plunges into the asthenosphere at subduction zones, and accummulates at its bottom. The floor of the asthenosphere may collapse flushing large volumes of cold material into the mesosphere. |
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| The movie from M. Gurnis (CalTec) shows how slabs break through the asthenosphere-mesosphere boundary and plunge into the mesosphere squeezing out the core/mantle boundary triggering the rise of hot mantle plumes. As they reach the Earth's surface, plumes produce massive volcanic activities, releasing large volumes of greenhouse gases that impact on the biosphere. For more: http://www.gps.caltech.edu/~gurnis/ |
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