Quarter 2 (Plate Tectonics, Layers of Earth) Flashcards
(25 cards)
What is the theory of Plate Tectonics?
The theory of Plate Tectonics is a scientific theory that describes the large scale motions on Earth’s lithosphere; theory of continental drift.
What causes the plates to move?
Plates at our planets surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move due to convection currents.
What is a convergent boundary?
Convergent Boundaries
• Occurs where plates push together
• Can be Continental to Continental, Continental to Oceanic, & Oceanic to Oceanic
Continental to Continental
• Same Density
• Forms Mountains
Oceanic to Oceanic
• One plate subducts beneath one another
•Forms Deep Ocean Trenches & Island Archs
Continental to Continental
• Occurs when ocean crest sinks under Continental crust
• Forms deep ocean trenches & coastal mountains
What features are found along a convergent boundary?
Mountains, Deep Ocean Trenches, & Island Archs, Volcanos
What is a divergent boundary?
Divergent Boundaries
• Occurs where plates move apart
• Most of these boundaries are found in the ocean
• Mid Ocean Ridges are a good example of divergent boundaries
What features are found along divergent boundaries?
Mid-Ocean Ridges
What is a transform boundary?
Transform boundaries occur when plates scrape past each other. Occurs on sea-floors near mid-ocean ridges. A land example is the San-Andreas fault in California
What is the only feature of transform boundaries?
Crust is neither made nor destroyed
What is a fault?
A fault is a fracture in Earth’s lithosphere
The San Andreas Fault in California is an example of what type of plate boundary?
Transform Boundary
What is subduction?
When one plate sinks beneath another
Along which type of plate boundary does subduction occur?
Convergent Boundary
Where do most earthquakes occur?
On the edges of the Pacific Ocean
What type of boundary creates new oceanic crust?
Divergent Boundaries
What type of boundary destroys oceanic crust?
Convergent Boundaries
What type of boundary neither creates nor destroys oceanic crust?
Transform Boundaries
In your own words state the theory of plate tectonics?
Plates that make up Earth’s lithosphere move over Earth’s surface
Describe what happens when two plates carrying oceanic crust collide.
The older plate carrying oceanic crust sinks because it is denser
Describe what happens when 2 plates carrying continental crust collide.
Both crust don’t sink because they have the same density.If they keep moving, the edges crumple & fold. In some cases this creates mountains.
Describe what happens when a plate carrying oceanic crust collide with a plate carrying continental crust.
The oceanic crust sinks because it is colder & denser than the continental crust.
Explain what force caused the movement of the continents from one supercontinent to their present conditions.
Convection Currents in the Asthenosphere cause the plate tectonics to move.
Breaks in the Earth’s Crust where rocks have slipped past each other are called __________.
faults
The lithosphere is broken into separate sections called ______________.
Tectonic Plates
A ___________ is a deep valley on land that forms along a divergent boundary.
Rift Valley
