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outer lithosphere and a plastic/ductile asthenosphere. 2. Earth has a stratified atmosphere, mainly composed of nitrogen (N. 2. ) and oxygen (O. 2. ) 4. The Earth has layers: a thin silicate crust, a thick iron- & magnesium silicate mantle, and ... attracts or repels magnetically charged or moving electrically charged objects.


than the crust. • Lithosphere versus asthenosphere: While the lithosphere behaves as a rigid body over geologic time scales, the asthenosphere deforms in ductile fashion. The lithosphere is fragmented into tectonic plates, which move relative to one another. There are two types of lithosphere: oceanic and continental.


Jul 28, 2005 ... In contrast, if the asthenosphere is weak owing to volatile enrichment or the presence of partial melt, the lithosphereasthenosphere boundary could occur over a much smaller depth range. Here we use converted seismic phases in eastern North America to image a very sharp seismic velocity gradient at ...


The earth is made up of layers (crust, mantle, outer core, and inner core). Each one has a unique make-up to it. Crust. This is the outer layer of the Earth about 10 miles or so thick. Mostly made up of rock and loose material. The crust found underneath continents is 3 times thicker than the crust underneath the oceans.


Old Ocean Basins: Flattening of the Heat Flow versus Age Curve. 226 ... Other Geophysical Constraints on the Thermal Regime of the Continental Lithosphere ..... both h1 and h2. The lithosphere preserves composi- tional heterogeneities in contrast to the well-mixed asthenosphere. Thus, its thickness can be defined by.


Sep 14, 2010 ... This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle. It was less dense than the ... Continental crust is also less dense than oceanic crust although it is considerably thicker(25 to 70 km versus 7-10 km). About 40% of the Earth's surface is now covered by ...


Magma and Plate Tectonics - Magma is fluid molten rock that exists under the Earth's crust. Learn about magma and ... These plates drift very slowly over the mantle below, which is lubricated by a soft layer called the asthenosphere. The activity at the ... Some plates move against each other rather than push or pull apart.


Aug 20, 2017 ... The rock of the asthenosphere is viscous rather than rigid and deforms slowly under stress, like putty. Therefore the lithosphere can move across or through the asthenosphere under the forces of plate tectonics. This also means that earthquake faults are cracks that extend through the lithosphere, but not ...


So at the top of the asthenosphere, the hot rock flows along the bottom of the lithosphere, transferring its heat to the cold rocks by conduction. The heat then flows ... Plate tectonics is the current "paradigm," or unifying philosophy, for understanding most of the geologic features on the surface of Earth. The development of ...