Unit 4 Plate Tectonics and the Rock Cycle Study Guide:
Rock Cycle:
 Know what determines whether a rock is igneous, metamorphic, or sedimentary.
 Know the two different general categories of each rock (i.e. plutonic/volcanic, contact/regional,
detrital/chemical).
 Be able to describe features which would help you identify whether a rock is igneous, sedimentary or
metamorphic.
 Be able to draw a rock cycle, showing ALL of the pathways.
Structure of the Earth and Isostasy:
 Know the definition of lithosphere, crust, asthenosphere and mantle.
 Understand why earthquakes occur.
 Be able to explain why continental crust is generally higher in elevation than oceanic crust, and why
ocean crust can subduct.
 Be able to explain why continents have thick “roots,” while oceanic crust does not.
 Be able to describe and/or draw a labeled diagram for the deformation lithosphere/asthenosphere
boundary under large mountains and mid-ocean ridges.
 Be able to explain and/or draw a labeled diagram explaining and showing why adding sediment in a river
delta, such as the Mississippi delta, will not raise the elevation above a certain level.
 Be able to explain why mountains can rise as they erode.
 Understand what isostatic equilibrium is.
Development of the Theory of Plate Tectonics:
 Know who Hutton and Wegener were, approximately when they lived, and what their ideas were. \
 Know what uniformitarianism and catastrophism are.
 Be able to explain evidence for plate tectonics, including
o Distribution of fossils, mountain chains, glacial flow patterns
o Shapes of continental margins
o Ocean floor bathymetry
o Ages of continental and ocean crust
o Paleomagnetic data for ocean floor and continental rocks
o Distribution of volcanoes and earthquakes
Forces and Processes Behind Plate Tectonics:
 Know what the driving forces are behind plate motions (i.e. sources of heat, sources of convection,
isostasy, slab push, ridge pull)
 Be able to explain the distribution of earthquakes and volcanoes as a result of plate motions and margin
types.
 Be able to explain the distribution and depth of Earthquakes for divergent, convergent, and transform
plate margins. How do they differ? Why do they occur at the depths they do?
 Know what decompressional melting is.
 Know why and where volatiles get added to a magma and what this does to the magma.
 Know how scientists measure rates of plate motion through the use of
o Hot spot tracks (see below)
o Orientation (including inclination) of iron-bearing minerals in igneous rocks (Paleomagnetism)
Divergent Plate Boundaries:
 Be able to draw a labeled diagram of a divergent margin, including features found there (rift valleys, midocean ridges (mountain chains), basalt flows, new ocean crust. Know what general type of igneous rocks
usually occur at divergent margins, and how and where they form. Know several examples of divergent
plate boundaries.
 Know what a triple junction is, where one occurs on Earth, and describe the motion of plates (with a
labeled diagram) that produces a triple junction.
Convergent Plate Boundaries:
o Oceanic-oceanic
o Oceanic-continental
o Continental-continental
 Be able to draw a labeled diagram of each of the types of convergent margins, including major features
found at each (such as island arcs, trenches, volcanoes, mountains, accretionary wedge, etc.).
 Be able give an example of where at least one of each occurs on Earth, and be able to recognize a
convergent plate margin based on its features. Also, know what kinds of igneous rocks typically form at
each of these places, if any, and how and where they form.
 Use quantitative data, as we did in lab, to determine the angle of subduction of a subducting slab. How do
we know where the slab is located beneath a plate?
Transform Plate Boundaries:
 Be able to describe the plate motion along a transform margin, features found at transform boundaries,
and where they usually occur.
 Be able to give an example of a transform plate boundary.
 Be able to tell which direction each plate is moving on each side of the boundary.
Hot Spots:
 Know what a hot spot is, the features found at hot spots, and where at least two hot spots occur on Earth.
 Know how to tell the difference between a chain of volcanoes formed by a hot spot, vs. a chain of
volcanoes formed at a convergent plate boundary.
 Know what type of igneous rocks erupt at hot spots, and evidence for where those magmas form in the
mantle.
 Know the differences in features between hot spots erupting through oceanic crust (i.e. Hawaii) vs.
continental crust (i.e. Yellowstone).
 Know how to calculate rates of plate movements by dividing the distance an extinct volcano (or caldera)
is from the current location of the hot spot (active volcanism) by the age of the extinct lava flows.
Examples of Plate Boundaries: For the following locations, know what type of plate boundary they represent. If
it’s converging, know whether it is continent-continent, continent-ocean, or ocean-ocean.
Aleutians
Alps
East Pacific Rise
Fractures between mid-ocean ridges
Great Rift Valley in Africa
Hawaii
Himalayas
Iceland
Island Arcs in the “Ring of Fire”
Japan
Mid-Atlantic Ridge
Pacific Northwest
San Andreas Fault
Yellowstone
Vocabulary: Here is a list of vocabulary terms you should be familiar with, in no particular order:
Island arc
lithosphere
hydrothermal circulation
viscous
Hot Spot
asthenosphere
flood basalt
uniformitarianism
Accretionary wedge
isostasy
plate margin
catastrophism
Seamount
bathymetry
converging
Pangea
Magma
rift valley
diverging
convection
Lava
mid-ocean ridge
transform
Paleomagnetism
triple junction
subduction
Igneous
trench
suture zone
Metamorphic
andesite
upwelling
Sedimentary
basalt
extrusive
Plutonic
caldera
intrusive
Volcanic
aseismic creep
magma
Detrital
shield volcano
silica