E ARTH ’ S I NTERIOR AND P LATE T ECTONICS Chapter 19, Section 1 Planet Earth

O BJECTIVES Identify Earth’s different geologic layers Describe the movement of Earth’s lithosphere using the theory of Plate Tectonics Identify the three types of plate boundaries and the principle structures that form at each of these boundaries Explain how the presence of magnetic bands on the ocean floor supports the theory of plate tectonics

K EY T ERMS Crust Mantle Core Lithosphere Plate tectonics Asthenosphere Magma Subduction fault

T HE E ARTH ’ S I NTERIOR Remember the model of the egg – The shell – The white – The yolk Different types of crust – Oceanic – Continental, (land) The mantle is a liquid – Magma below – Lava at the surface

T HE E ARTH ’ S T EMPERATURE The deeper you move through the crust, the warmer it gets, (-100 degree F in the coldest spot on Earth), up to 347 degrees F The mantle is 2280 degree F The Core is degrees F due in part to radiation

P LATE T ECTONICS Alfred Wegener pieced together, (just a little joke), evidence for the movement of the lithosphere over the liquid mantle. – The coast-line of the continents look like puzzle pieces – Fossil evidence suggests similar animals/plants on both continents across the oceans Structures on the ocean floor give evidence of a mechanism for movement or “continental drift” (magnetic rock bands)

H OW DO THE PLATES MOVE ? H EAT RISING !

T HE P LATE B OUNDARIES Divergent – the crust separates because the tectonic plates are pulling away from each other exposing new lava that cools to rock Convergent – plates are being pushed together so the boundaries collide, (earthquakes) – Forming mountains, sub-duction zones & volcanoes Transform Fault, (earthquake zones) – Can happen anywhere the forces are strong enough to break rock, (faults)

S UMMARY The layers of the Earth are the crust, mantle, and core Earth’s outer layer, (lithosphere), is broken into several pieces called plates The plates ride on top of the soft, liquid mantle, (asthenosphere), beneath the plates Plates spread apart at divergent boundaries, collide at convergent boundaries, and slide past each other at transform fault boundaries

S UMMARY The entire landscape of our planet has been shaped and re-shaped by these processes The alignment of iron and other magnetic minerals in oceanic crust near divergent boundaries supports the theory of plate tectonics.

D EFINITIONS Crust is the outermost and thinnest layer of Earth Mantle is the layer of (liquid) rock between the crust and the core Core the center of a planetary body The core of the Earth is semi-solid to liquid Lithosphere is the thin outer shell of the Earth Consisting of the crust and rigid upper mantle

D EFINITIONS Plate tectonics is the theory that the Earths lithosphere is made of large moving plates Asthenosphere is the part of the mantle that is moving due to convection currents in the mantle Magma molten, melted rock within the Earth Subduction is a process where one tectonic plate goes beneath another tectonic plate into the mantle A Fault is a crack in the Earth created by stress and fracture of the rock, (may be anywhere)