 From the surface of the Earth the layers are the crust, mantle, outer core, and inner core.

 The Lithosphere is the Earth’s crust and the upper part of the mantle. This layer contains the tectonic plates on Earth.

 The Asthenosphere is the layer of liquid magma in the mantle below the Lithosphere. A convection current occurs in the asthenosphere causing the Earth’s plates to move.

 Alfred Wegener believed that all of the continents were once connected into a super continent landmass called Pangaea. Wegener believed that over time the continents drifted apart. This theory is called Continental Drift.

 Same fossils found on different continents  Continents fitting like puzzle pieces  Migration paths of animals  Rock structures

 The sea floor spreads at mid-ocean ridges.  Mid-oceans ridges are under water mountain chains.  Magma rises at mid-ocean ridges, solidifies, and new crust forms.  Older Crust is pushed farther away from the ridge closer to the continents.  Scientists discovered that the rocks farther away from the ridge were older because they were able to examine rock samples from drilling on the sea floor.

 Here is an image of how the magma flows from the mid-ocean ridges:

 This is the largest mid-ocean ridge and the longest mountain chain in the world.

 There are three main types: Divergent, Convergent, and Transform. Divergent Convergent Transform

 Boundary between two plates that are moving apart  Crustal Features=mid ocean ridges at two ocean plates and rift valleys at continental plates

Plates move away from each other

 Boundaries between two plates that are colliding  There are 3 types of convergent plate boundary collisions: Ocean-Ocean Ocean-Continent Continent-Continent

Continental-Oceanic Collisions Oceanic-Oceanic Collisions Continental-Continental Collisions

 Subduction is the process of a denser crust sinking beneath a less dense crust and back into the mantle. This occurs at Convergent Plate boundaries. This causes trenches and volcanoes. Active volcanoes are only located at plate boundaries.

 Continental plate and oceanic plate collide  The denser oceanic plate sinks (subducts) beneath the less-dense continental crust  Trenches are found at this kind of plate boundary.

 Oceanic plate collides with another oceanic plate  The denser of the 2 oceanic plates sinks (subducts)  Volcanic islands are formed at this boundary.  Trenches are found at this kind of plate boundary as well.

 A continental plate colliding with another continental plate  This collision causes mountains ranges on the middle of continents.  The Himalayas Mnts. in Asia are an example of this kind of collision.

 Boundary between two plates that slip past each other moving in opposite directions  Theses boundaries create faults, such as the San Andreas fault. Earthquakes form along these faults. San Andreas Fault

 Here is the San Andreas fault. It is an example of a transform boundary. ◦ The Pacific plate (west of fault) is moving northwest ◦ The North American plate (east of fault) is moving southeast Pacific Plate

 These maps show detailed shapes of Earth’s surface. It represents different elevations specifically on mountains.  Topographic maps contain contour lines that represent the elevations. When the Contour lines are close together, it indicates a steep slope.

 A long chain of active volcanoes and other tectonic features such as earthquakes at the plate boundaries surrounding the Pacific plate