Science Chapter 6 Lesson 2 2-Column Notes
What Are Plates and How Do They Move? Pp. 240-244
Name____________________________#_____
Earth’s Plates
Fit like jigsaw puzzle
Lithosphere
Rigid upper mantle, made of plates of rock. Some plates
10,000km +, some smaller. Some mostly oceanic while others
are mostly continental
Asthenosphere
Plates sit on asthenosphere. Flows like taffy, pliable.
Plate tectonics
Plate boundaries-3 types
Theory that lithosphere is divided into plates that
are always moving Plate movements build Earth’s largest
landforms. Move, break, shrink, grow
2 or more plates move away from each other.
Divergent boundaries

Mid-ocean ridge

Rift

Sea-floor spreading
Example--Mid Atlantic Ridge
Transform fault boundaries
Example-- San Andreas Fault
Convergent boundaries

Continental>Continental
ex.

Continental>oceanic
ex.

Oceanic >oceanic
ex.
Chain of mountains that run through oceans
Deep valley where plates move apart-plates separate
and hot rock from
mantle moves up and forms new crust-new lithosphere
This process is sea floor spreading
2 plates move past each other. Crust is NOT formed
or destroyed. Plates grind against each other in opposite
directions. Causes earthquakes
2 plates push into each other.
•Plates bend and fold forming mountain ranges
Himalayas- Mt Everest
•Oceanic sinks under continental forming mountains a
nd volcanoes
and trench
•One plate sinks under the other causing a deep trench and
melting of asthenosphere
Plate Movements
Change Earth’s Surface
Evidence of movement
Pangea
Shapes of continents
Rock types along edges of continents
Same kinds of plants and animals fossils
Earth’s magnetic field in rocks
Matching rock types
Atlantic is growing; Pacific Ocean is shrinking; Af
rica is shifting north