Plate Tectonics

When did the supercontinent Pangaea start to break up?

200 million years ago

When did the Himalayan Mountain Range begin to form?

40-50 million years ago

Volcanic Arc

A arc-shaped chain of volcanoes formed above a subduction zone.

What happens when the ocean floor cracks

A crack in the ocean floor appears and then magma oozes up from the mantle to fill in the space between the plates, forming a raised ridge called a mid-ocean ridge. The magma also spreads outward, forming a new ocean floor and new oceanic crust.

divergent boundary

A plate boundary where two plates move away from each other.

transform boundary

A plate boundary where two plates move past each other in opposite directions

convergent boundary

A plate boundary where two plates move toward each other.

Volcano

A vent in the earth's surface through which magma and gases erupt

What is the name of this tectonic plate?

African Plate

Pangea was named by which German scientist

Alfred Weagner

Which scientist is credited with proposing the ideas that led to the development of the plate tectonics theory?

Alfred Wegener

Transform boundaries and the resulting faults produce many earthquakes because edges of tectonic plates are jagged rather than smooth.

As the plates grind past each other, the jagged edges strike each other, catch, and stick, "locking" the plates in place for a time

The tectonic plates float on which semiliquid layer?

Asthenosphere

This solid layer of the earth is made of mostly iron and nickel

Inner Core

Which of the earth's layers is broken into several large tectonic plates?

Lithosphere

Which of these layers is found directly above the earth's core?

Mantle

Magma

Molten rock, gases, and solid crystals and minerals

Trench

Molten rock, gases, and solid crystals and minerals. A steep-sided depression in the ocean floor.

What is NOT likely to happen at a divergent boundary?

Mountain formation

What type of crust is found under the oceans?

Oceanic crust

What is happening at the subduction zone of the Juan de Fuca and North American Plates?

One plate is being pulled under another.

What happens when crust moves apart.

One result of huge masses of crust moving apart is seafloor spreading. This occurs when two plates made of oceanic crust pull apart.

What is the earth's only liquid layer?

Outer Core

What is the name of this tectonic plate?

Pacific Plate

Approximately 225 million years ago, the earth's continents were grouped into one landmass. What is the landmass called?

Pangaea

This animation depicts which of the following?

Rift formation

What is the name of this tectonic plate?

South American Plate

Mid-ocean ridges are places where tectonic plates are doing what?

Spreading apart

This animation depicts which of the following?

Subduction zone

Subduction Zone

The area where one plate is being pulled under the edge of another

. At transform boundaries, tectonic plates are not moving directly toward or directly away from each other. Instead, two tectonic plates move past each other in a horizontal direction. This kind of boundary results in a fault. A fault is a crack or fracture in the earth's crust that is associated with this movement.

These create earthquakes because edges of tectonic plates are jagged rather than smooth, locking the plates in, and creating stress

As the crust widens and thins, valleys form in and around the area, as do volcanoes

These volcanoes become very active

What happens when two continental plates collide?

They fold the rocks at the boundary, creating a mountain.

At some convergent boundaries, an oceanic plate collides with a continental plate. Oceanic crust tends to be denser and thicker than continental crust, so the denser oceanic crust gets bent and pulled under, or subducted, beneath the lighter and thicker continental crust.

This forms a subduction zone

At transform boundaries, tectonic plates are not moving directly toward or directly away from each other. Instead, two tectonic plates move past each other in a horizontal direction.

This kind of boundary results in a fault. A fault is a crack or fracture in the earth's crust that is associated with this movement.

Because the plates are locked together without moving, a lot of stress builds up at the fault line

This stress is released in quick bursts when the plates suddenly slip into new positions. The sudden movement is what we feel as the shaking and trembling of an earthquake.

The plates move in opposite directions building up tension until they slip causing earthquakes.

Transform

What kind of plate boundary is found where the North American and Caribbean Plates meet?

Transform boundary

Another type of boundary neither creates nor consumes crust. This type of boundary is called a _________________ boundary because two plates move against each other, building up tension, then release the tension is a sudden jerk of land called an ___________________

Transform, Earthquake

When the oceanic crust sinks, what is formed near continents?

Trenches

Mountain formation can result when which of the following occurs?

Two continental plates collide.

The place where the two plates meet is called a ____________________. Boundaries have different names depending on how the two plates are moving in relationship to each other.

boundary

When two _______________ plates diverge, a valley-like rift develops. This rift is a dropped zone where the plates are pulling apart

continental

The plates move away from each other allowing magma to create new ocean crust.

Divergent

What kind of plate boundary runs across Iceland?

Divergent boundary

Which of the following geologic events can occur at a transform boundary?

Earthquake

What is the border between two tectonic plates called?

Boundary

What leads to the creation of island arcs?

Collision of two oceanic plates

What type of crust is found under the continents?

Continental crust

Which of these statements is correct?

Continental crust is thicker than oceanic crust.

Which of these concepts is part of the theory of plate tectonics?

Continents are in slow constant motion.

The boundary where two plates meet and trenches are formed.

Convergent

What kind of plate boundary is found at the meeting point of the Philippine and Pacific Plates?

Convergent boundary

What is the earth's outermost layer?

Crust

A subduction zone is also generated when two oceanic plates collide — the older plate is forced under the younger one, and it leads to the formation of chains of volcanic islands known as ____________ ___________.

island arcs

The crust continues to be forced deeper into the earth, where high heat and pressure cause trapped water and other gasses to be released from it. This, in turn, makes the base of the crust melt, forming ________

magma