chapter 2 section 3

what role do transform boundaries play?

transform boundaries connect other segments of plate boundaries.

what is the relationship between transform plate boundaries and mid-ocean ridges?

transform boundaries connect segments of mid-ocean ridges

why are volcanoes not found at transform boundaries?

transform boundaries do not cause changes to pressure, temperature, or composition to the mantle

when do new oceans form?

when a continent is broken apart by a divergent boundary

where do most divergent boundaries originate?

within continents

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

earth would increase in volume

what is an example of modern-day mantle plume volcanism?

hawaiian islands

what about about nemataths and volcanic arcs is true?

in a volcanic arc, any of the volcanoes can be active at any time; volcanic arcs are associated with convergent plate boundaries; nemataths and volcanic arcs are both the result of volcanic activity

the east pacific rise separates which two tectonic plates?

the nazca plate and the pacific plate

what do all plate boundaries have in common?

they are all associated with zones of earthquakes

what do ridges and rises have in common?

they are both associated with divergent plate boundaries; new seafloor is created at each

what is the rate of spreading at the east pacific rise? is this considered fast or slow?

16 centimeters (6.4 inches) per year; it's considered fast

what is the rate of spreading at the mid-atlantic ridge? is this considered fast or slow?

2.5 centimeters (1 inch) per year; it's considered slow

what is a mantle plume?

a circular column of magma that rises from deep within earth

the red sea is an example of what kind of plate boundary?

a continental-continental divergent

what often forms after continental rifting?

a new ocean basin

what is a volcanic arc?

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

what are examples of modern-day island arcs?

aleutian islands, mariana islands

where is the youngest ocean floor found?

along the crest of mid-ocean ridges

the east african rift is a divergent plate boundary that is splitting the continent of africa into two pieces. what will eventually form around this divergent boundary?

an ocean

which mountain ranges are examples of continental arcs?

andes and cascades

numerous small, shallow earthquakes tend to occur where?

at divergent plate boundaries

in general, where do both earthquakes and volcanic eruptions occur?

at divergent plate boundaries and convergent plate boundaries

in general, where do volcanoes form in subduction zones?

on the overriding plate, away from the convergent boundary

how are island arc and continental arc magmas similar?

both are formed near subduction zones

how are continental rift magmas and continental arc magmas different?

continental arc magmas are more vicious than continental rift magmas

the gulf of california is an example of what kind of plate boundary?

continental-continental divergent

what causes melting of material under divergent plate boundaries?

decompression of rock

iceland is located on what type of plate boundary?

divergent

what accurately describes a segment of the mid-ocean ridge spreading at a rate of 3 centimeters per year?

it would have a prominent and deep rift valley; it would be classified as an oceanic ridge

list of common tectonic settings associated with volcanic activity

mantle plumes, continental arcs, continental rifts, island arcs

where are most divergent plate boundaries found?

mid-ocean ridges

which geologic features are associated with divergent boundaries?

mid-ocean ridges and continental rift valleys

what forms at divergent plate boundaries?

new oceanic lithosphere

do fracture zones near transform boundaries play a role in plate motion?

no; fracture zones play no role in plate motion

which type of faulting is associated with the development of new ocean floor?

normal faulting

which geologic features are associated with convergent plate boundaries?

ocean trenches and volcanoes

the andes mountains is an example of what kind of plate boundary?

oceanic-continental convergent

the peru chile trench is an example of what kind of plate boundary?

oceanic-continental convergent

the mariana trench is an example of what kind of plate boundary?

oceanic-oceanic convergent

where are continental volcanic arcs found?

on the overriding plate near a subduction zone

how do plates move at divergent plate boundaries?

plates move apart

how do plates move at transform plate boundaries?

plates move side by side in opposite directions

how do plates move at convergent plate boundaries?

plates move together

how do ridges and rises differ?

rises are broader and more gently sloped than ridges

transform boundaries are classified under what type of fault?

strike-slip

a trench and chain of volcanoes known generally as a volcanic arc are always present when there is what?

subduction

what is the relationship between the crust and the lithosphere?

the crust is part of the lithosphere

what is a present-day example of a continental rift?

the east african rift valley