Geol ch. 2 Plate Tectonics

lithosphere

earth's outermost solid layer, includes the crust and the uppermost part of the upper mantle. relatively strong, cooler outer, layer of the earth

transform plate boundaries

edges of two adjacent plates are parallel to the direction in which one of the plates is moving in.

Oceanic crust

found beneath the deeper seafloor of major ocean basins, covering around 63% of earth's surface.

Complete this statement: Divergence is to moving away as convergence is to _______.

moving toward

What is peridotite?

the rock making up the mantle

Which of the following best represents the relationship between earthquakes and tectonic plates?

More earthquakes are found along tectonic plate boundaries than within a single tectonic plate.Friction exists along plate boundaries, both at the surface and further down. The stress of plate motion builds strain in the rocks until the friction is overcome.

Which of the following mountain ranges are examples of continental arcs?

Andes and Cascades

What kind of tectonic boundary would be evidenced by down-dropped blocks of rock and shallow-focused earthquakes?

Divergent boundary

You are visiting Key West, Florida. Which tectonic plate are you on, and what is the nearest adjacent plate?

North American Plate; Caribbean Plate

In which of the following regions does the greatest number of people live in areas exposed to the risk of earthquakes?

On the continental portion of southeastern Asia, as well as the islands off of the coast, regions with high population density have had frequent earthquakes.

Which of the following bodies of water is associated with seafloor spreading?

Red Sea

Of the physical features listed, which is associated with the greatest earthquake hazard?

Sierra Nevada

Why is decompression melting common at mid-ocean ridges but not at subduction zones?

Tectonic plates are moving apart at mid-ocean ridges, resulting in a lowering of pressure beneath the ridge. Tectonic plates are moving together at subduction zones, resulting in an increase of pressure under new mountains.

What would happen to Earth if ocean floor were created at divergent boundaries at a faster rate than it is destroyed at convergent boundaries?

The Earth would increase in volume.

Why is water a necessary component of the melting process in subduction zones?

The addition of water lowers the melting temperature of rock.

What is the relationship between the crust and lithosphere?

The crust is part of the lithosphere.

Volcanoes

Volcanoes are commonly found along subduction zones, where continental and oceanic plates collide. Friction generated by the plate interaction, as well as internal heat from Earth (endogenic energy), produces conduits of magma along fault zones.

Where does the water involved in melting at subduction zones come from?

Water contained within minerals in the subducting plate is released during metamorphism.

What is a volcanic arc?

a row of volcanoes that forms on the overriding plate near a subduction zone

Earth has:

a thin solid crust, on top of a thick solid mantle. Over a core composed mostly of iron with a liquid outer core and a solid inner core.

Where is the youngest ocean floor found?

along the crest of mid-ocean ridges

asthenosphere

below the lithosphere, hotter and much weaker layer in the mantle. hot enough to contain some magma, almost entirely solid but is weak and able to flow like silly putty.

A pattern of earthquakes that are shallow at the plate boundary and get progressively deeper are evidence of a _____ plate boundary. An example of this is found in __________.

convergent; Western South America

Which two processes commonly generate magma?

decompression melting and wet melting (the addition of volatiles)

Which of the following could cause rock to melt?

decrease in pressure, increase in temperature, change in composition

Plates move apart at __________ boundaries, move together at __________ boundaries, and move side-by-side at __________ boundaries.

divergent/convergent/transform

Which geologic features are associated with divergent boundaries?

mid-ocean ridges and continental rift valleys

divergent plate boundary

moving away from each other, include oceanic lithosphere along mid ocean ridges.also continental rift zones.

Which geologic features are associated with convergent boundaries?

ocean trenches and volcanoes

convergent plate boundary

plates are moving toward each other. Subduction,

Which of the following evidence does NOT support plate tectonics?

presence of magnetic field

continental crust

underlies the part of earth's surface from a couple of km below sea level to the top of earth's highest peak

GPS data can be used to track the rate and direction of plate movement. If a GPS unit measures a latitude velocity of 28.2 mm/yr and a longitude velocity of 59 mm/yr, what is the velocity of plate motion?

65.4 mm/yr

Which of the following states has the greatest earthquake hazard?

California