4.1-Plate Tectonics

4.1-Plate Tectonics

Concept Check

Objective

• Describe the geological changes and events that occur at convergent, divergent and transform boundaries.

Multiple Choice

Which layer of the Earth consists of dense mass of solid nickel, iron, and radioactive elements that release massive amount of heat

• Crust

• Core

• Mantle

• Lithosphere

• Asthenosphere

The Earth's core is the part of Earth in the middle of our planet. It has a solid inner core and a liquid outer core. The temperature of the outer core ranges from 8,000 °F in the outer regions to 11,000 °F near the inner core.

Multiple Choice

Which statement best describes the asthenosphere?

• very outer layer of the lithosphere, earth’s surface

• Liquid layer of magma surrounding core, kept liquified by intense heat from core

• thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

• solid, flexible outer layer of mantle, beneath the lithosphere

Asthenosphere, zone of Earth’s mantle lying beneath the lithosphere and believed to be much hotter and more fluid than the lithosphere. The asthenosphere extends from about 100 km (60 miles) to about 700 km (450 miles) below Earth’s surface.

Earth's Structure

Core-

Mantle: liquid layer of magma surrounding core, kept liquified by intense heat from core

Asthenosphere:

Lithosphere: thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

Crust: very outer layer of the lithosphere, earth’s surface

Multiple Choice

Which of the following best describes the action at a divergent boundary?

• Plates move away from each other

• Plates move towards each other

• Plates slide past each other in opposite directions

Multiple Choice

Which of the following best describes the action at a convergent boundary?

• Plates move away from each other

• Plates move towards each other

• Plates slide past each other in opposite directions

Divergent: Rising magma from mantle forces plates apart and forms mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

Transform: Earthquakes

Convergent: Leads to subduction and forms mountains, island arcs, earthquakes, and volcanoes

• Magma heated by earth’s core rises towards lithosphere

• Rising magma cools & expands, forcing oceanic plates apart mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”

• Magma cools, and solidifies into new lithosphere

• Spreading magma forces oceanic plate into cont. Sinking oceanic plate melts back into magma Also forces magma up, creating, coastal Mtns. & volcanoes on land

Tectonic Map Can Predict...

Hotspots: areas of esp. hot magma rising up to lithosphere

Mid-ocean Islands (iceland, Hawaii)