Operations Center Staff Directory. Administration Org Chart. Instructional Services Org Chart. Public Information Logo and Guidelines. Technical Services Org Chart. A cross section of Earth showing the following layers: 1 crust 2 mantle 3a outer core 3b inner core 4 lithosphere 5 asthenosphere 6 outer core 7 inner core.
This animation shows the layers by composition and by mechanical properties. The crust is very thin, relative to the radius of the planet.
There are two very different types of crust, each with its own distinctive physical and chemical properties, which are summarized in Table below. Oceanic crust is composed of mafic magma that erupts on the seafloor to create basalt lava flows or cools deeper down to create the intrusive igneous rock gabbro Figure below. Gabbro from ocean crust. The gabbro is deformed because of intense faulting at the eruption site. Sediments, primarily muds and the shells of tiny sea creatures, coat the seafloor.
Sediment is thickest near the shore where it comes off the continents in rivers and on wind currents. Continental crust is made up of many different types of igneous, metamorphic, and sedimentary rocks.
The average composition is granite, which is much less dense than the mafic rocks of the oceanic crust Figure below. Because it is thick and has relatively low density, continental crust rises higher on the mantle than oceanic crust, which sinks into the mantle to form basins.
This granite from Missouri is more than 1 billion years old. The lithosphere is the outermost mechanical layer, which behaves as a brittle, rigid solid. The lithosphere is about kilometers thick. Look at the figure above. Can you find where the crust and the lithosphere are located? How are they different from each other? The definition of the lithosphere is based on how earth materials behave, so it includes the crust and the uppermost mantle, which are both brittle.
Since it is rigid and brittle, when stresses act on the lithosphere, it breaks. This is what we experience as an earthquake. Mantle The two most important things about the mantle are: 1 it is made of solid rock, and 2 it is hot. Scientists know that the mantle is made of rock based on evidence from seismic waves, heat flow, and meteorites.
The properties fit the ultramafic rock peridotite, which is made of the iron- and magnesium-rich silicate minerals Figure below. Peridotite is rarely found at Earth's surface. Peridotite is formed of crystals of olivine green and pyroxene black. Scientists know that the mantle is extremely hot because of the heat flowing outward from it and because of its physical properties. Convection in the mantle is the same as convection in a pot of water on a stove. Convection currents within Earth's mantle form as material near the core heats up.
As the core heats the bottom layer of mantle material, particles move more rapidly, decreasing its density and causing it to rise. When the geotherm crosses the solidus, partial melting starts to occur in the asthenosphere at the depths indicated on the diagram. If this magma escapes to the surface, it will erupt and form a volcano.
If the lithosphere thins sufficiently, the geotherm can cross the solidus and partial melting occurs. Asthenosphere —The asthenosphere is made of very viscous, ductile, semi-solid material on which the lithosphere moves. It is a solid that can behave like a liquid, and it is about km thick. There are three basic ways that rocks melt to form the lavas that erupt from volcanoes: decompression, addition of volatiles, and conduction.
Below the lithosphere is the asthenosphere layer, a much hotter and malleable portion of the upper mantle. The asthenosphere begins at the bottom of the lithosphere and extends approximately km into the Earth. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Psychological disciplines What are 3 ways the asthenosphere is different from the lithosphere?
Psychological disciplines. Ben Davis February 9, What are 3 ways the asthenosphere is different from the lithosphere? What is the difference between the lithosphere and the asthenosphere quizlet? What is the difference between lithosphere asthenosphere and mesosphere? What is an interesting fact about the asthenosphere? What are the similarities and differences between the asthenosphere with the lithosphere? Something that appears to be solid on a short time scale can, in fact, be liquid.
Over long periods of time glass can flow, forming for example windowpanes with thick bottoms and thin tops in old buildings. The mantle is like this. When it is under stress for long periods of time, it can flow. Due to the incredibly high temperatures and pressures near the center of the Earth, the outer core is liquid iron and nickel, while the inner core is solid.
The motion of the liquid outer core is what gives Earth its magnetic field. Take a look at how temperature in the earth change with depth. The image above of the layers of the Earth is very simplified.
Much in the way that we can use a stick figure to represent a person but lacks all of the detail, a wealth of information is missing in order to highlight the general distinctions between the layers of the Earth. Skip to main content. The Structure of the Earth Since we humans live on the very surface of the Earth, we do not tend to think too much about what is beneath the basements of our homes and workplaces.
Layers of the Earth. Temperature with depth in the Earth.
0コメント