Plate Tectonics Quiz

Where are deep sea trenches formed?

In a subduction zone, when two plates collide and one subducts under because it is more dense.

If a rock had a dark color and small crystals, how was it formed and what elements do it contain?

It had an extrusive magma placement and a fast cooling rate. It contains iron

The grayer or darker a rock is, the more... there is

There would be more iron

What are plates tectonics (where, how many plates, and actions of them)?

They are located in the lithosphere 14 plates make up Earth They move and interact at their boundaries (plate edge

A slow cooling rate= ______________ crystals and an __________________ magma placement.

A slow cooling rate= larger crystals and an intrusive magma placement.

What is a subduction boundary?

A type of convergent boundary

What rock type is found in oceanic crust and why is it more dense than the continental crust?

Basalt it is high in iron (more dense than silicon and oxygen)

What is the continental crust high in and is it less dense or more dense than the oceanic crust?

Continental crust is high in silicon and oxygen and it is less dense (granite)

What rock type is found in continental crust and why is it less dense than oceanic?

Granite It is high in silicon and oxygen (less dense than iron)

In a convection current, imagine it being C B D A What force causes the convection cell to turn down at point C?

Gravity is pulling it down

What scientist and what year was the theory of seafloor spreading discovered?

Henry Hess 1960s

What is intrusive and extrusive magma placement?

Intrusive-coming up through the lithosphere Extrusive-volcanic eruption

What is the theory of plate tectonics and around when was it thought of.

It explains *how and why* continents drift. It states that Earth's crust and the upper mantle (lithosphere) are broken up into plates and these plates move. late 1960s

If a rock has small crystals and a light color, how was it formed and what elements do it contain?

It had an extrusive magma placement and a fast cooling rate (think this because crystals are small, so they cool faster) It contains silicon and oxygen

If a rock had a light color and large crystals, how was it formed and what elements do it contain?

It had an intrusive magma placement and a slow cooling rate. It contained silicon and oxygen.

If a rock had a dark color, large crystals, how was it formed and what elements do it contain?

It had an intrusive magma placement and a slow cooling rate. It contains iron

Where is Earth's core in relation to the mantle and crust?

It is below all of it.

How do convection currents work?

It is due to the density and changes of temperature in the mantle. The core is giving off heat so the magma is heated, becoming less dense and rising up. Then it hits the crust which stops it making it go to the side and it cools, becoming more dense and going down. (cycle) The flow that transfers heat within a fluid caused by changes in temperature and density, along with the force of gravity. Convection currents in the mantle are caused by heat from the Earth's core.

What is the oceanic crust high in and is it less dense or more dense than the continental crust?

It is high in iron which makes it more dense(basalt)

What is the force that drives plate tectonics?

Mantle convection

What features are formed at transform boundaries (and what is not and why)

No land is created/destroyed, no volcanic activity because no subduction but faults and earthquakes occur when the energy is released. Example: The California Fault

What layers subduct and which do not, and WHY? (during the boundaries--transform, convergent,subduction, and divergent)

No layers subduct in transform boundaries (no volcanic activity) No layers subduct in convergent boundaries because the two plates are both less dense than the mantle. In subduction boundaries, when it is oceanic/oceanic the less older oceanic subducts. When it is oceanic/continental, the oceanic subducts because it is older. No subduction in divergent boundaries.

Explain subduction

Oceanic crust sinks under continental crust during collision due to density It forms deep sea trenches The oceanic crust subducts->higher temperatures->rocks melt->crust is destroyed

What is the difference between rocks that are formed through *slow cooling* and *fast cooling*?

Slow cooling-occurs inside of Earth (intrusive), larger crystals form because they have more time to form. Fast cooling- occurs on the surface of Earth (extrusive), smaller crystals form because there is less time for them to form

In a convection current (arrows going to the left), where is the least dense and most dense point? C . B D . A

The bottom left point (D) would be the *most dense* because it just went down. C would be the lowest temperature because it sinks down B is less dense because it just rose up A is the *least dense* because it wants to rise up, moving further apart

How do convection currents (mantle convection) drive plate tectonics?

The convection currents (circular motion) moves the plate tectonics Look at the diagram (moves in direction of arrows)

What part of the Earth's layers is broken up into plates?

The lithosphere

What features are formed at convergent boundaries? ( and what is not and why) Give example:

The main formation formed are mountain ranges. They are formed when the two continental crusts push up because they are both less dense than the mantle. There is no volcanic activity because no plates are subducted. Example: The Himalaya Mountain Range where the Indian and Eurasian plates are currently in collision. The Appalachian Mountain Range in North America

What is the asthenosphere made up of?

The middle mantle

Where does mantle convection occur?

The middle mantle/asthenosphere

Why does the oceanic crust sink under the continental crust?

The oceanic crust sinks under continental crust during collisions due to density since it is more dense than the continental crust.

Where is the oldest and youngest seafloor found?

The oldest seafloor is found furthest away from the mid-ocean ridge. The youngest is the closest to the mid-ocean range.

What happens at transform boundaries (actions of plates, what type of plates, describe diagram (draw on paper if you can)?

The two plates could either slide past each other in opposite directions or go in the same direction but at a different rate. Oceanic/oceanic Continental/continental It is unlikely for it to happen in continental. Plate edges are jagged, not smooth and when they slide past each other, they might stick or catch on at certain points and this puts stress on the plates. When the stress is released and plates slide past each other, this sudden movement is felt as an earthquake (releases energy).

What is the lithosphere made up of?

The upper mantle, oceanic crust, and continental crust

What features are formed at divergent boundaries? (and what is not and why) Give example:

There is volcanic activity because magma comes through the rift. Volcanoes form at the sides of the rift when the magma flows up. Rift can fill with water and become a lake. Divergent boundaries can separate plates and also break them up. Rifts can widen into valleys that collect water and then form lakes or seas. Crust can eventually separate into 2 separate continents as widening continues. O/O plates pull apart-forms mid ocean ridges (seafloor spreading ) C/C plates pull apart--forms ridges

The more pink a rock is, the more ..... there is

There would be more silicon and oxygen (less dense)

What happens at divergent boundaries (actions of plates, what type of plates, describe diagram (draw on paper if you can)?

They are created when two plates move apart, creating a rift valley. Over time, they may get bigger and become mid ocean ridges. Magma comes up from where the plates separate. Two plates are moving apart from each other Continental/continental oceanic/oceanic The plates do not subduct, they pull apart and form rifts (dropped zone where crust widens and thins) Can occur in any type of place but mostly in oceanic

What are the mid-ocean ridges and what are they detected by?

They are long chains of mountains on the ocean floor and are detected by sonar

What do the plate tectonics float on top of?

They float on top of the asthenosphere

What happens at convergent boundaries (actions of plates, what type of plates, describe diagram (draw on paper if you can)?

Two plates collide and they push up to form a mountain chain. Continental/continental When two continental plates collide, neither one can be subducted into the mantle because both of them have a density that is much lower than the mantle's density. Since neither plate can be subducted, they have to go up, creating large mountain chains

What happens at subduction boundaries (actions of plates, what type of plates, describe diagram (draw on paper if you can)?

Two plates come together (converge), one plate goes UNDER the less dense plate, magma rises at subduction zones (where denser plate sinks and melts into magma Oceanic/oceanic oceanic/continental Two oceanic crusts collide and create deep sea trenches which are the deepest part of the ocean. An oceanic plate colliding with a continental plate creates mountains and volcanoes on top of the continental When it is o/c, the oceanic is denser so it subducts. When it is o/o the older plate subducts because it is denser.

What happens to the oldest oceanic crust?

Two plates come together (converge), one plate goes UNDER the less dense plate, magma rises at subduction zones (where denser plate sinks and melts into magma)

What features are formed at subduction boundaries? ( and what is not and why) Give example:

When part of the crust melts from magma, it will come back and cut through the crust making volcanic islands in chains called island arcs. It creates deep sea trenches, mountains, and volcanoes Example: Ring of Fire O/C collisions: deep sea trench volcanoes mountains tsunamis O/O collisions: island arcs deep sea trenches earthquakes (tsunamis)

What is igneous rock?

cooled magma

Cooling rate

how fast magma cools, crystal sizes depend on how fast cooling took place

Magma placement

location where magma cools/solidifies

What is seafloor spreading?

magma rises from inside of Earth up to mid-ocean ridges magma flows sideways and spreads, creating new seafloor hot less dense material below Earth's crust rises up to surface at mid-ocean ridges

*NOTE*-- the color of a rock determines the elements it contains the crystal sizes of the rock determine the magma placement and cooling rate

the color of a rock determines the elements it contains the crystal sizes of the rock determine the magma placement and cooling rate

What are the three main layers of the Earth?

the crust, the mantle, the core