* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Earth`s Layers
Survey
Document related concepts
History of geomagnetism wikipedia , lookup
Geochemistry wikipedia , lookup
Deep sea community wikipedia , lookup
Post-glacial rebound wikipedia , lookup
History of geology wikipedia , lookup
Tectonic–climatic interaction wikipedia , lookup
Abyssal plain wikipedia , lookup
History of Earth wikipedia , lookup
Age of the Earth wikipedia , lookup
Future of Earth wikipedia , lookup
Plate tectonics wikipedia , lookup
Transcript
Earth’s Layers (2015) 7th Grade Earth Science Unit Earth is made of 4 layers • Crust- thin outermost layer – Continental crust is oldest, thickest, less dense and made of granite – Oceanic crust is younger, thinner, denser and made of basalt • Mantle- 80 % 0f the volume of the earth. – Upper mantle is rigid, below is the asthenosphere which is a plastic like layer on which the tectonic plates float. – There is a huge difference in temperature between the outer mantle and the inner mantle. – This difference in temperature sets up a convection current which is responsible for the cracking and moving of the tectonic plates. • Outer Core- liquid layer directly below the mantle (Fe, Ni) • Inner Core- solid innermost layer of earth( Fe, Ni) – Inner core is solid because the pressure is too great to allow it to be liquid Andrija Mohorovicic • Yugoslavian scientist, discovered in 1909 that earthquake waves near the surface moved slower than ones passing through the interior. • Discovered that P-waves were deflected in the interior. • Decided the crust was less dense then the mantle due to the fact that waves move faster through denser material. • Boundary b\w mantle and crust named Moho discontinuity. Lithosphere • Made of the crust and upper layer of the mantle • Broken into 12 large pieces called Plates Crust • Where we live • Made of basalts and granites • 2 types– Oceanic b\w 3-5mi. Thick • Is youngest, thinnest, more dense and made of Basalt – Continental ~25mi. Thick • is oldest, thickest, less dense and made of granite Temperature ranges b\w air temp. – 1600*F Mantle • • • • • Largest layer 1800mi. thick Very hot dense rock (mostly S,O,Fe,Mg) 1600*F @ top and 4000*F @ bottom. Consistency of asphalt Convection Currents- are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over. (responsible for movement of the plates) Asthenosphere • Layer below the lithosphere, zone of asphalt like consistency (part of mantle that flows) Outer Core • Made of iron and nickel in the liquid state • 1800mi. under crust and is 1400mi. thick • Temp. range b\w 4000*F and 9000*F. Inner Core • Pressure so great that metal core stays solid. • Starts @ 4000 mi. under crust, 800 mi. thick • Temp. may reach 9000*F • Pressure ~ 45,000,000 pounds per sq. in.