Earths Internal structure When a meteorite impacts a planet or moon, its energy of motion(called kinetic energy) is transformed into heat energy. As earth grew larger and larger from continual impacts its temperature increased a Radioactive decay of materials like uranium thorium and potassium also added heat
Earth’s Internal Structure ◼ When a meteorite impacts a planet or moon, its energy of motion (called kinetic energy) is transformed into heat energy. ◼ As Earth grew larger and larger from continual impacts, its temperature increased. ◼ Radioactive decay of materials like uranium, thorium and potassium also added heat
Earth's Internal structure Because Earth became partly fluid, less dense molten materials(silicon, aluminum, sodium, and potassium) were freed to migrate toward the surface a Denser melted materials. such as molten iron, sank toward the center of the planet
◼ Because Earth became partly fluid, lessdense molten materials (silicon, aluminum, sodium, and potassium) were freed to migrate toward the surface. ◼ Denser melted materials, such as molten iron, sank toward the center of the planet. Earth’s Internal Structure
TThe earth’ s Interior Planet Earth has three main parts: At the center is the densest part the core (metallic iron, nickel). Surrounding the core is the mantle Surrounding the mantle lies the thinnest and outermost layer the crust
The Earth’s Interior ◼ Planet Earth has three main parts: ◼ At the center is the densest part, the core (metallic iron, nickel). ◼ Surrounding the core is the mantle. ◼ Surrounding the mantle lies the thinnest and outermost layer, the crust
Ocean Crust Oceanic crust Moho Asthenosphere Mantle 150 Liquid Lithosphere Continental outer core crust Solid Vertical scale is 10x Inner the horizontal scale 0 km Continental crust thickness Temperature and pressure Mesosphere: hot but stronger Increase due to high pressure with depth 350km 100km Asthenosphere hot, weak, plastic rfac osphere cool, rigid, brittle Inside earth
Inside Earth
TThe earth’ s Crust a The crust is not uniform a The oceanic crust on average is about 8 km thick The continental crust on average is a bout 45 km thick
The Earth’s Crust ◼ The crust is not uniform. ◼ The oceanic crust on average is about 8 km thick. ◼ The continental crust on average is about 45 km thick
Investigating the Earths Interior a How do we know anything about the composition of the core and the mantle? By measuring the time required for earthquake waves to travel through earth by different paths, we can determine the composition of the materials through which they move. a Iron meteorites are believed to be fragments from the core of a small terrestrial planet that was shattered by a gigantic impact
Investigating the Earth’s Interior ◼ How do we know anything about the composition of the core and the mantle? ◼ By measuring the time required for earthquake waves to travel through Earth by different paths, we can determine the composition of the materials through which they move. ◼ Iron meteorites are believed to be fragments from the core of a small terrestrial planet that was shattered by a gigantic impact
The Layers of the Earths Interior ( 1) The inner core Pressures are so great that iron is solid, despite its high temperature. a The outer core a Iron is molten and exists as a liquid. The Mesosphere The mantle between the bottom of the asthenosphere to the core-mantle boundary. The temperature at the core-mantle boundary is about 500000
The Layers of the Earth’s Interior (1) ◼ The inner core ◼ Pressures are so great that iron is solid, despite its high temperature. ◼ The outer core ◼ Iron is molten and exists as a liquid. ◼ The Mesosphere ◼ The mantle between the bottom of the asthenosphere to the core-mantle boundary. ◼ The temperature at the core-mantle boundary is about 50000C
The Layer of the Earth's Interior(2) The asthenosphere: The region of the mantle where rocks become ductile, have little strength, and are easil deformed. It lies at a depth of 100 to 350 km below the surface The Lithosphere The outer 100 km of the solid earth where rocks are harder and more rigid than those in the plastic asthenosphere
The Layer of the Earth’s Interior (2) ◼ The Asthenosphere: ◼ The region of the mantle where rocks become ductile, have little strength, and are easily deformed. It lies at a depth of 100 to 350 km below the surface. ◼ The Lithosphere: ◼ The outer 100 km of the solid Earth, where rocks are harder and more rigid than those in the plastic asthenosphere
Plate Tectonics (1) The earth gets rid of heat and keeps a nearly constant internal temperature through convection in the mesosphere and asthenosphere ■ Plate tectonics theory says that earth’s outermost100km“ eggshell”(the lithosphere) is cracked in about a dozen large pieces
Plate Tectonics (1) ◼ The Earth gets rid of heat and keeps a nearly constant internal temperature through convection in the mesosphere and asthenosphere. ◼ Plate tectonics theory says that Earth’s outermost 100 km “eggshell” (the lithosphere) is cracked in about a dozen large pieces
Plate Tectonics(2) In the 1960s research by many geologists and oceanographers melded into the revolutionary hypothesis of plate tectonics. Plate tectonics is a group of processes by which large fragments(plates) of lithosphere move horizontally across the surface of the earth Through their movements and interactions they generate: ■ Earthquakes. Volcanism Mountain-building Other geologic processes
Plate Tectonics (2) ◼ In the 1960s, research by many geologists and oceanographers melded into the revolutionary hypothesis of plate tectonics. ◼ Plate tectonics is a group of processes by which large fragments (plates) of lithosphere move horizontally across the surface of the Earth. Through their movements and interactions, they generate: ◼ Earthquakes. ◼ Volcanism. ◼ Mountain-building. ◼ Other geologic processes
