Continental Drift Theory The hypothesis that Earth’s continents move on Earth’s surface. Wegner proposed this theory Sea Floor Spreading a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out. Subduction The process by which an oceanic tectonic plate sinks under another plate into Earth’s mantle. Convection currents A circulation pattern in which material is heated and rises in one area, then cools and sinks in another area, flowing in a continuous loop.

Pangaea A hypothetical supercontinent that included all of the landmasses on Earth. It began breaking apart about 200 million years ago. Mid-Ocean Ridge A long line of sea-floor mountains where new ocean crust is formed by volcanic activity along a divergent boundary. Continental-Oceanic Convergent A boundary along which a plate carrying oceanic crust sinks beneath another plate with continental crust. C-O-C Subduction Zone Oceanic-oceanic Convergent A boundary along which a plate carrying oceanic crust sinks beneath another plate with oceanic crust. O-O-C

Continental-Continental Convergent Transform Boundary A boundary along which two tectonic plates scrape past each other, and crust is neither formed nor destroyed. Convergent Boundary A boundary along which two tectonic plates push together, characterized either by subduction or a continental collision. Divergent Boundary A boundary along which two tectonic plates move apart, characterized by either a mid-ocean ridge or a continental rift valley. Continental-Continental Convergent It is when two tectonic plates move against each other creating folded mountain ranges C-C-C Ex. Mid-ocean ridge or continental rift valley Ex. Forms a folded mountain Ex. Fault lines (where earthquakes happen)

Continental-Continental Divergent Two tectonic plates separate causing rift zones (deep cracks between the plates) C-C-D Oceanic-Oceanic Divergent Two tectonic plates separate causing magma to rise and fill the gap. The magma cools and forms a new sea floor (sea floor spreading) O-O-D Earthquake- typically occur at transform boundaries Fault-a break in the Earth’s crust Folded Mountain -formed after two plates converge (collide) Volcano- areas of Earth’s surface which magma & volcanic gases come out of (can happen along Oceanic Convergent boundaries)