structure? Heavier‚ denser material sink toward the core while light less dense material rise to the surface. Their separation in layers is dependent on the density of the material. 3. Contrast the physical make-up of the asthenosphere and the lithosphere. asthenosphere – weak sphere‚ exists below a depth of about 100 kilometers; its rock is easily deformed lithosphere – sphere or rock‚ consists of the entire crust and uppermost mantle and forms Earth’s relatively cool‚ rigid outer shell 4
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Describe in basic terms how elements were/are formed during the big bang (including the reasons why only H/He formed abundantly)‚ during normal stellar operation (including why some elements such as Si and Fe were formed more abundantly)‚ and during supernova processes/explosion Big bang only thing that forms out of the big bang is the nuetrons. Protons plus electrons = hydrogen. Hydrogen fuses the helium. There are no stable atoms with 5 or 8 nucleons (hydrogen would have 5‚ helium would have
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in the first decades of 20th century. According to the Plate Tectonic theory‚ the lithosphere breaks up into the tectonic plates. Currently‚ there are seven or eight major plates in the Earth. Generally‚ the lithospheric plates remain on the asthenosphere. All the plates move in relation to one another and according to this rule‚ three plate boundaries are formed. Such as: the collisional or convergent boundaries‚ spreading center or divergent boundaries and transform or conservative boundaries
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tectonics is also referred to as the conveyor belt principle. Earlier theories proposed gradual shrinking or gradual expansion of the globe. Tectonic plates are able to move because the Earth’s lithosphere has a higher strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge and drag‚ downward suction‚ at the subduction zones. Another explanation
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The layers of Earth How do scientists know what is in the center of the earth? How can we know what the core of the earth is made of‚ if scientists have never studied any materials from a depth below 7.5 miles? Earth is approximately 4.6 billion years old‚ and over this time period‚ many things have changed inside and out. The formation of our planet is quite amazing. Earth consists of multiple layers. The three most distinct or main layers are the core‚ mantle and crust. The inner portion is
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Subductive boundaries occur where two plates (one continental and one oceanic) are moving toward each other. The denser plate‚ the oceanic‚ is forced underneath the continental. As it subducts into the asthenosphere‚ it begins to turn back into magma. This magma is light and less dense than the asthenosphere‚ so it rises and forces its way through weaknesses in the crust. This is how volcanoes are formed on subductive margins. An example‚ is the Aleutian Islands which are a chain of volcanoes formed by
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lithosphere‚ their movements and how these movements has influenced changes in the surface’s topography (Strahler‚ 2011‚ 389). The driving force that causes these plate movements is the gradual movement of the semi-molten rock that makes up the asthenosphere (Kious‚ 1996‚ 28). Features observed at these margins share some similarities but‚ also vary quite largely. These differences are caused by the different movements displayed at each boundary and the types of plates involved; oceanic or continental
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Earth Lithosphere- Strong‚ rocky‚ outer shell of the solid Earth including all the crust and the upper part of the mantle to a depth of 100 km. forms the plates Asthenosphere- weak‚ ductile layer of the mantle beneath the lithosphere; deforms to accommodate motions to the overlying plates. Deep Mantle- Mantle beneath the asthenosphere Outer Core- Liquid shell composed of mostly iron Inner Core- Innermost sphere composed primarily of solid iron. Crust: COLD‚ RIGID‚ THIN SURFACE Continental
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divergent boundaries‚ convergent boundaries‚ and transform boundaries. At a divergent boundary the lithosphere breaks apart on parallel faults that move outward from each other. The plates break apart the block between the two faults sink into the asthenosphere creating a rift and pushing magma upward to fill in the crack. With a convergent boundary the plates move toward each other with one plate subducted under another plate. At the location where the plate sinks under another plate is called the subduction
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Crust - silicate rocks‚ primarily granite and basalt * Oceanic Crust - mostly basalt * Continental Crust - igneous‚ metamorphic‚ and sedimentary rocks * The Mantle - iron and magnesium rich silicate rocks * Upper Mantle (Asthenosphere) * Lower mantle (Mesosphere) * The Core - iron nickel alloy * Outer core * Inner core The Crust The crust of the earth is very slowly growing thicker. Volcanic activity is continually adding mass to the crust. Though
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