Plate Tectonics Chapter 17
Continental Drift _________ proposed the theory that the crustal plates are moving over the mantle. This was supported by fossil and rock type evidence; also matching of coastline shapes. Wegener
Convection Currents The force responsible for plate movement is __________.
Plate Boundaries The following two slides show maps of the current major plate boundaries and their relative motions. You should be able to describe various landforms created by different plate movements.
Plate Boundaries Divergent Boundary – moving _____ Convergent Boundary – moving ________ Transform Fault Boundary – moving ________________________ apart together sideways past each other
Divergent Boundaries Boundary between two plates that are moving apart or rifting RIFTING causes SEAFLOOR SPREADING
Features of Divergent Boundaries Mid-ocean ridges rift valleys fissure volcanoes
Divergent boundary of two continental plates. Creates a __________. Example: _____________ rift valley East African Rift
Divergent boundary of two oceanic plates. Known as seafloor spreading Example: Mid Atlantic Ridge
Convergent Boundaries Boundaries between two plates that are colliding There are 3 types…
Type 1 Ocean plate colliding with a less dense continental plate Subduction Zone: where the less dense plate slides under the more dense plate VOLCANOES occur at subduction zones
Andes Mountains, South America
Type 2 Ocean plate colliding with another ocean plate The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH
Aleutian Islands, Alaska
Type 3 A continental plate colliding with another continental plate Have Collision Zones: a place where folded and thrust faulted mountains form.
Convergent boundary of two oceanic plates. Creates an ________ and a _____. Example: _____ island arctrenchJapan
Convergent boundary of an oceanic plate and a continental plate. Forms a _______ mountain range and a ______. Examples: _______ or _______ Mts volcanic trench Cascades Andes
Convergent boundary of two continental plates. Forms a ______ mountain range. Examples: ___________, Alps, ______________ folded Himalayas Appalachians
Transform Fault Boundaries Boundary between two plates that are sliding past each other EARTHQUAKES along faults
San Andreas Fault, CA
Transform-fault boundary where the North American and Pacific plates are moving ____ each other. Example: ________________ in California past San Andreas Fault
Plate Boundaries Review Places where plates move apart are called _____________ boundaries. When continental plates diverge a ___________ is formed. When two oceanic plates converge what is created? _________________ The Appalachians formed mainly from continental plate collisions and therefore are a __________ mountain range. The force moving the plates is ____________. Convection currents divergent rift valley an island arc and a trench folded