SCIENTISTS AND INTERNAL STRUCTURE OF EARTH

• Andrija Mohorovicic (1909) - Yugoslavian scientist who discovered the Mohorovicic discontinuity, a boundary between the mantle and crust.
• Mohorvicic discovered that there is difference in density between crust and mantle
• Mohorovicic found out that the velocity of seismic waves changes.
• Beno Gutenberg - a German scientist who identified the mantle-core boundary called Gutenberg discontinuity.
• Gutenberg discontinuity - boundary between mantle and core.
• Inge Lehmann (1936) - Danish scientist who discovered that innercore is solid and outercore is liquid.
• Inge Lehmann discovered the Lehmann discontinuity, the boundary between inner and outer core.
• Inner core - 5000 degrees celsius and consist of solidified nickel and iron. 2600km diameter
• Outer core - 2000 degrees celsius and consist of molten nickel and iron. 2250km diameter
• Pressure Freezing - occurs when matter solidifies not because of low temperature but because of extreme pressure.
• Asteroids are made up of chrondite
• Chondrite - made up of elements like iron, silicon, magnesium, oxygen, and nickel.
• Earth and meteorites have almost the same densities. Thus, earth's mantle rock and meteorites minus its iron have the same density
• Mantle - intermediate zone between crust and core, consist mostly of solid rocks.
• Mantle makes up 80% of the earth's volume and 68% of earth's mass.
• Mantle's approximate thickness is 2,900km and temperature of ranging 15,000 (lower mantle) to 30,000 (upper mantle) degrees celcius.
• Mantle is mainly made up of silicate rocks
• Silicate rocks are composed of elements silicon, iron, oxygen, and magnesium
• Mantle is solid since p-wave and s-wave can travel through it
• Mantle has 3 regions: Upper mantle, transition zone, lower mantle
• Asthenosphere - low velocity zone; soft, weak top layer of the upper mantle made up of hot molten materials. Thickness of 180km and temperature of 300 to 800 degrees celcius
• Crust - thinnest and rocky outer layer of the earth. It has 2 types: continental and oceanic
• Continental crust is mainly made up of Na, O, Si, Al, K, Ca. Thickness is 35-40km.
• Oceanic crust is composed of basalt. Thickness of 7-10km
• Element composition of crust: Oxygen (46.60%), Silicon (27.72%), Aluminum (8.13%), Iron (5%), Calcium (3.63%), Sodium (2.83%), Potassium (2.59%), Magnesium (2.09%), Titanium (0.40%), Hydrogen (0.14%)