PLATE TECTONICS- Chapt.17 Flashcards
Two theories for plate tectonics.
Continental Drift, Seafloor Spreading
Name evidences that can help support the continental drift.
- Similarity of the Atlantic coastlines of Africa and South America.
-Antarctica and Australia had nearly identical late Paleozoic rocks and fossils -German Scientist Alfred Wegener’s Works.
Who is the German meteorologist and geophysicist who formulated the first complete statement of the continental drift hypothesis.
Alfred Wegener
What supports Wegener’s observations?
-Wegener reassembled the continents to form one supercontinent, Pangaea.
-Wegener thought that the similar rocks and fossils were easier to explain if the continents were joined together, rather than in their present positions.
It is a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.
Seafloor Spreading
It is a continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers (40,390 miles).
The Mid-Ocean Ridge
These are long, narrow depressions on the seafloor. These chasms are the deepest parts of the ocean.
Oceanic Trenches
Plates that move away from each other/ Magma rises from the mantle creating new crust/ Often associated with mid-ocean ridges.
Divergent Boundaries
-Plates move towards each other/ Subduction zones occur when an oceanic plate sinks beneath a continental plate.
Convergent Boundaries
Plates slide past each other horizontally/ Tectonic plates grind, causing earthquakes along transform faults/ No creation or destruction of crust occurs at transform boundaries.
Transform Boundaries
What are some of the causes of plate motion? List a few.
-Mantle Convection
-Gravity
-Slab Pull and Ridge Push
-Mantle Composition
-Basal Drag
-Trench Suction
-Mantle Plumes
-Paleomagnetic Evidence
