2 Earth’s InteriorEarth’s interior is divided into layers: the crust, mantle, & core, based on composition. Although the Earth’s crust seem stable, the extreme heat of the Earth’s interior causes changes that slowly reshape the surface.
4 The CrustOutermost layer of earth made of rock that forms earth’s outer skin5 to 100 km thick, average thickness is 35 kmthinnest layerless than 1% of Earth’s massComposition of crust: oxygen, silicon, aluminum, calcium, iron, sodium, potassium, magnesium
5 The Crust Oceanic Crust Continental Crust crust beneath the oceans consist mainly of dense rock (basalt - dark in color)5-8 km thickContinental Crustcrust that forms the continentsconsist mainly of less dense rock (granite - lighter in color)30 km average thickness
6 Crust to MantleThe upper part of the mantle and the crust together form a rigid layer called the lithosphere.Lithos is greek for stone, 100 km thickmade of pieces called tectonic plates
7 Tectonic PlatesThe tectonic plates are pieces of the lithosphere that fit like pieces of a jigsaw puzzle and move on top of the asthenosphereMay Consist of both Continental and Oceanic Crust
8 Major tectonic plates: Pacific plate North American plate Cocos plate Nazca plate Antarctic PlateSouth American Plate Eurasian Plate Indian Plate Australian Plate
9 Crust to MantleThe asthenosphere is a soft layer of the mantle on which pieces of the lithosphere moveasthenes is Greek for soft or weakmaterial is like warm tar and can flow slowlyThe rigid crust and lithosphere float on the hot, plastic material of the asthenosphere.
10 The Mantle layer of rock between crust and core 2900km thick, 67% of Earth’s massComposition - silicon, oxygen, iron and magnesiumphysical conditions in mantle change because pressure and temperature increase with depthtemp ranges from 870 ºC to 2,200ºC
11 Convection Currents inside the Mantle Hot columns of mantle material rise slowly through the asthenosphere
13 The Core Innermost layer of the Earth 6800 km in diameter (3,400 km from outside edge of core to center of core)1/3 of Earth’s mass, 15% of its volumeTemperature ranges from 2,000 ºC to 5,000ºCConsist of 2 parts; Inner Core and Outer Core
14 The Outer Corelayer of molten metal (iron and nickel) beneath the mantlesurrounds the inner core2,200 km thick
15 The Inner Core dense ball of solid metal (iron and nickel) extreme pressure from layers above1200 km, from outside edge of inner core to center
16 Earth’s Magnetic Field Currents in the liquid outer core force the solid inner core to spinThe inner core spins inside the Earth at a slightly faster rate than the rest of the planetThis movement creates the Earth’s magnetic field
17 Earth’s Magnetic Field The earth acts as a giant bar magnetEarth’s magnetic fields have reversed more than 177 times in the last 85 million years