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