What is the GEOSPHERE?

All solid parts of EarthRocks, soils, minerals, sediments, magma

The Grand Canyon, AZ

https://www.youtube.com/watch?v=WwiiOjyfvAU

What are the layers of the Earth?

Layers of the Earth

1. Crust- O, Si, Al 2. Mantle- O, Si, Mg,

Fe3. Core- Fe, Ni

• Geologists classify Earth’s layers two ways: chemically and physically• Chemical – by composition• Physical- by structureChemical Layers of the

Earth

Physical Layers of the Earth

• Lithosphere–Crust and upper mantle combined–Broken in chunks called tectonic plates–Oceanic plates are thinner and denser than continental plates

• Asthenosphere- Layer of Jello-like magma in the mantle- Tectonic plates move due to convection currents in the asthenosphere

Physical Layers, cont.Mesosphere

The rest of the mantle; molten rock

Outer CoreLiquid metalSurrounds inner core

Inner CoreDensest layerSolid metal

Theory of Plate TectonicsLithosphere (upper mantle and crust) is divided into pieces called tectonic plates.

These plates glide across the underlying asthenosphere like ice drifts across a pond.

Continents are located on tectonic plates and move around with them

Seafloor Spreading1.Magma rises from

asthenosphere2.Creates new oceanic

lithosphere3.Pushes tectonic plates

apart

Seafloor-Spreading

If new crust is being created by the process of seafloor spreading, is the Earth

growing!?

SubductionSubduction zones: A region where old crust is destroyed as it is pulled back down into the mantle

Plate BoundariesThe area where two plates meet is

called a plate boundary.Most earthquakes and volcanoes

occur at or near plate boundaries

Three main types of plate boundaries:1.Divergent- separating2.Convergent- colliding3.Transform- scraping past

Transform Boundaries

• 2 plates slide past each other

• Not smooth. Plates lock, and build up tension. After too much tension builds, the plates “snap” causing earthquakes

Divergent Boundaries

• When two plates separate

• Most common on ocean floor

• Creates Mid-Ocean Ridge

Divergence Forms New Ocean Floor

Convergent BoundariesThree Main Types:

1.Continental & Oceanic- causes deep ocean trench and land volcanoes Ex: Andes Mountains

2. Continental & Continental- causes large land mountain ranges Ex: Himalayan Mountains

3. Oceanic & Oceanic- causes deep ocean trench and island arc (chain of volcanic mountains) Ex: Mariana trench and islands

Subduction Zone Continental + Oceanic Crust

Continental + Continental Crust

Subduction Zone Oceanic + Oceanic Crust (another view)

Subduction ZoneOceanic + Oceanic Crust

Some videos for your viewing pleasure…

Plate Movement:https://www.youtube.com/watch?v=kwfNGatxUJIhttp://www.youtube.com/watch?v=ryrXAGY1d

mE&feature=endscreen&NR=1San Andreas Fault:

http://www.youtube.com/watch?NR=1&v=ZxPTLmg0ZCw&feature=endscreen

Exit Ticket1. Arrows in the block diagram below

show the relative movement along a tectonic plate boundary. What is this type of plate boundary called?

a. transform plate boundaryb. convergent plate boundaryc. divergent plate boundaryd. subduction plate boundary

Exit Ticket2. When two tectonic plates collide,

oceanic crust usually subducts beneath continental crust because oceanic crust is primarily composed of igneous rock that is:

a. thin and less denseb. thick and less densec. thin and more densed. thick and more dense

Exit Ticket3. The block diagram below shows

the boundary between two tectonic plates. Which type of plate boundary is shown?

a. divergentb. transformc. convergent d. complex

Exit Ticket4. The Himalaya Mountains were

formed in a collision at a:

a. divergent boundaryb. convergent boundaryc. transform boundaryd. fracture zone

Exit Ticket5. In which Earth layer are most

convection currents that cause seafloor spreading thought to be located?

a. crustb. outer corec. asthenosphere d. inner core

Earthquakes Worldwide

Tectonic Plates

Active Volcanoes