Chapter 27 Review

The supercontinent that broke up at the start of the Mesozoic Era to form the continents we have today.

The theory that the ocean floor widens as the mid-ocean ridge separates.

An extinct group of seed plants that arose during the Permian through the Triassic Period.

Magnetism preserved or fossilized in rocks. It can often tell us about changes in the orientation of rock bodies after their formation.

The study of ancient life preserved as fossils in the rocks.

The orientations of major geologic features such as mountain belts, continental shields, stable platforms, and areas of folded and deformed rocks.

An ocean island that has no remaining central volcanic edifice, but exists only as a coral reef almost completely at or below sea level.

A curved line of volcanic islands all (or almost all) of which contain active volcanoes

A straight line of islands of volcanic origin where only the largest island contains an active volcano.

A line of underwater volcanic vents that marks a diverging plate boundary.

When two continents collide, the denser continent is subducted.

True False

Faults like the San Andreas form when two continents diverge.

True False

Pangaea was the first and only time all of the continents have been together.

True False

Island arcs colliding together form into continents over time.

True False

Scientists widely accepted the theory of continental drift when Wegener proposed it.

True False

Opposition to scientific theories can make theories more concrete.

True False

All questions about the breakup of Pangaea have been answered.

True False

Basalt can lose its magnetic orientation if it is heated above the Curie temperature.

True False

Guyots are rounded seamounts found on the ocean floor.

True False

The geometric fit of the continents is seen by matching the continents'

shorelines ages continental shelves

The magnetic "stripes" on the seafloor are explained by which of the following ideas?

Glossopteris flora Reversals of Earth's magnetic field Compressional folding and erosion of the ocean floor

Plate boundaries are clearly indicated by the location of which of the following?

Earthquakes Coastlines Mountain ranges

An example of a transform boundary is which of the following?

The Mid-Atlantic ridge The San Andreas fault The Himalayas mountains

Divergent plate boundaries may occur in which of the following?

Only oceanic lithosphere Only continental lithosphere Both oceanic and continental lithosphere

The occurrences of the Glossopteris flora in Permian rocks of South America, Africa, Antarctica, India, and Australia is evidence that:

these plants lived in the southern hemisphere since the Permian Period. these plants can survive in a wide variety of climates. the southern landmasses have separated since the Permian period. the southern landmasses have become closer since the Permian period.

Which of the following is not evidence for continental drift?

Changes in Paleozoic trilobites in North America and Europe. The presence of glossopteris on several continents. Glaciated Permian rocks on several continents. The geometrical fit of North America and Australia.

The alternating stripes of strong and weak magnetism found in rocks of the seafloor

parallel the oceanic ridges. are perpendicular to the ocean ridges. are oblique (at an angle to, other than perpendicular) to the ocean ridges. are too far for the oceanic ridges to judge their relationship.

Convergent plate boundaries do not involve

subduction zones. mountain-building events. creation of new oceanic lithosphere creation of linear island chains.

Among the following choices, an earthquake would least likely occur

in a young fold mountain belt. in a continental shield. at a transform fault. along the ocean ridge system. along an ocean trench.

In the figure below the magnetic field of the basalt on either side of a mid-ocean ridge is indicated with shading. The light areas have magnetic fields that point north, and the dark areas have magnetic fields that point south. These patterns were important in evidence that helped develop the plate tectonic model. Why?

The reverse polarity (grey) bands are all older than the normal polarity (white) bands, giving alternating stripes of young and old rock. The bands occur symmetrically to each side of the ridge where new ocean crust is slowly being made. The Earth's magnetic field flips, and the field in the basalt points the same direction as the Earth's field when the rock formed. As rocks age, their magnetic fields change directions, so measuring the strength and direction of the magnetic field in the basalt allows us to accurately date the age of the rock. The magnetic field indicates the direction that the plate was moving. Alternating bands prove that the ocean alternately spreads and closes. The bands only occur in regions where the ocean crust is coming together to form a ridge, and temperatures and pressures are high enough to force the magnetic field in the rocks to change direction

The least amount of plate tectonic activity would be found in which of these locations?

The California coastline area The Canadian shield Iceland Japan

How does a study of earthquakes and seismic waves provide evidence in favor of the plate tectonic theory?

The pattern of earthquake activity corresponds to plate boundaries. Wave velocities are related to plate motion. Seismic studies have determined the boundary between the mantle and the core. Seismic waves power continental drift. Earthquakes are regarded as the energy source for tectonic plate motion.

A converging plate margin bisects the Mediterranean Sea. What will be the probable outcome of this situation?

The Mediterranean will shrink A mid-ocean ridge will soon begin to emerge within this area. The water body will grow longer as a result of shear transform faulting. The water body will grow wider. A rift valley will appear in the middle of the Mediterranean.

Which of the following features are most commonly associated with converging plate boundaries between two continental plates?

Oceanic ridges Island arcs Fold mountain belts Hot spots More than one of the above

How does the plate tectonic model account for the movement of continents?

The continents float on the surface of the liquid core of the earth. The continents move/cut through the rock of the lithosphere, albeit very slowly. The continents rest on plates which move on top of a layer of mechanically weak (plastic) rock in the earth. The continents have a layer of liquid rock underneath them that allows them to slide over the ocean crust. Plate tectonics is unable to explain continental drift.

A divergent plate margin runs through the middle of the Atlantic Ocean. What happens to the Atlantic as a result of the presence of this diverging plate boundary?

The Atlantic will shrink. Folded mountains will soon begin to emerge as islands in the middle of the Atlantic. Atlantic will grow wider. The Atlantic will grow shorter as a result of shear transform faulting. Volcanic island arcs will emerge in the middle of the Atlantic.

The picture below shows the plates. The Andes mountain range is found on the west coast of South America. What direction is the Nazca plate moving assuming that the South American Plate is stationary?

North South East West It is not moving.

Why does a transform boundary typically form?

To connect a divergent and convergent boundary To connect segments of a spreading center ridge To provide a means for subduction to occur To release pressure built up from mantle plume activity

Which of the following data does NOT play a major role in the evidence for the plate tectonic theory?

Geologic "fit" of adjacent continents. The age distribution of the rocks of the sea floor. Orientation of paleomagnetic fields in ancient lava flows. The percentage of the total continental area that is taken up by stable platform. Fossil record on adjacent continents.

Chapter 27 Review

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