chapter 19- plate tectonics

Divergent plate boundaries can occur where spreading occurs under a continent, for example ___. A. the Red Sea B. the Himalayan Mountains C. the Alps D. the Gulf of Mexico E. the Mediterranean Sea

A

Harry Hess proposed that the _______. A. sea floor moves B. continents drift C. magnetic field reverses D. magnetic poles wander E. the core is liquid

A

In plate tectonics, intense geologic activity occurs at ____. A. plate boundaries B. ocean floor C. continental interiors D. along coastlines E. along mountain ranges

A

The Rift Valley in East Africa is an example of a _____. A. diverging plate boundary B. converging plate boundary C. transform plate boundary D. back arc spreading center E. continental rise

A

The inner wall of a trench consists of a(n) _____ of thrust-faulted and folded marine sediment and pieces of oceanic crust. A. accretionary wedge B. subduction wedge C. large amount of sea D. active volcano consisting E. a gap

A

The isotopic ages of Hawaiian Island basalts increase regularly to the ____. A. northwest B. east C. north D. south E. northeast

A

A divergent boundary on the sea floor is associated with ______. A. submarine trenches B. mid-oceanic ridges C. transform faults D. aseismic ridges E. guyots

B

In this hypothesis the two sides of the mid-oceanic ridge are moving in opposite directions like slow conveyor belts. A. plate tectonics B. sea floor spreading C. continental drift D. continental collisions E. plate spreading

B

One kind of convergent plate boundary is ____. A. rift valley convergence B. continent-continent convergence C. transform convergence D. subduction zone convergence

B

Plate motion can be measured directly using ____. A. FBI B. GPS C. USGS D. NOAA E. GIS

B

Sea-floor spreading implies that sea-floor rocks should be ______________. A. the same age throughout B. youngest on the crest of mid-ocean ridges C. younger as water become colder D. younger toward the trench E. youngest on the continental shelf

B

These plate boundaries are marked by shallow-focus earthquakes in a narrow zone for a single fault or in a broad zone for a group of parallel faults. A. divergent B. transform C. ocean-continent convergence D. subduction E. ocean-ocean convergence

B

Wegener reassembled the continents to form the super continent _____. A. Asia B. Pangea C. Laurasia D. Gondwanaland E. Madagascar

B

During extension in divergent plate boundaries a rift valley forms as a central ____. A. horst B. strike-slip fault C. graben D. mountain range E. subduction zone

C

One possible mechanism for plate tectonic drive is ____. A. meteor impacts B. earthquake energy C. slab pull D. gravity sliding E. Benioff drive

C

The Himalayan Mountains are thought to have formed ____. A. by continent-ocean convergence B. by ocean-ocean convergence C. by continent-continent convergence D. at a spreading center E. at a transform fault

C

The Peru-Chile trench is moving over the ________ Plate as South America moves west. A. North American B. Australian C. Nazca D. South American E. Antarctic

C

The San Andreas Fault is _________ in California. A. a normal fault B. an oblique fault C. a transform fault D. a thrust fault E. a reverse fault

C

The ___ includes rocks of the crust and uppermost mantle. A. true ocean basin B. asthenosphere C. lithosphere D. ophiolites E. Moho

C

The downward plunge of cold rock at convergent boundaries accounts for the existence of _____. A. continental shelves B. submarine hot springs C. oceanic trenches D. the Earth's core E. the abyssal plains

C

The head of large plumes that form "hot spots" may cause uplift and ____. A. andesitic volcanoes B. transform faults C. vast fields of flood basalt D. spreading centers E. subduction zones

C

This type of plate boundary the two plates can consist of ocean-ocean, ocean-continent, or continent-continent crust. A. divergent B. strike-slip C. convergent D. transform E. transverse

C

____ is the idea that continents move freely over Earth's surface, changing their positions relative to one another. A. Plate tectonics B. Sea floor spreading C. Continental drift D. Continental collisions E. Plate spreading

C

____ volcanoes can be found along subducting plate boundaries. A. Shield B. Cinder cone C. Andesitic D. Basaltic E. Pegmatitic

C

A _____ plate boundary is where plates are moving away from each other. A. convergent B. shear C. transform D. divergent E. transverse

D

In the early 1900s the German meteorologist _____ made a strong case for continental drift. A. Charles Plummer B. George Bush C. Ben Franklin D. Alfred Wegener E. Diane Carlson

D

Magma heated by ocean-continent convergence may form a(n) _____ such as the Aleutian Islands. A. mantle diapir B. convection uplift C. abyssal plain D. magmatic arc E. hot spot

D

Measured rates of sea-floor spreading range from ______ cm/year. A. 0.1 to 1 B. 100 to 1000 C. 1000 to 10,000 D. 1 to 24 E. 0.01 to 0.1

D

Pangea initially separated into two parts, the southern part is called ____. A. Rodinia B. Laurasia C. Panthallasia D. Gondwanaland E. Atlantis

D

The basic idea of ______ is that the Earth's surface is divided into a few large plates that move slowly relative to one another. A. continental drift B. sea floor spreading C. mantle plumes D. plate tectonics E. isostasy

D

Young mountain belts with their associated igneous intrusions, metamorphism, and fold- thrust belts form at _______. A. divergent boundaries B. continental rifts C. transform fault boundaries D. convergent boundaries E. hot spots

D

_______ proposed an explanation for magnetic anomalies. A. Charles Plummer B. Harry Hess C. Alfred Wegener D. Vine and Matthews E. Diane Carlson

D

Alternating positive and negative polarity magnetic anomalies in the crust form a stripe- like pattern parallel to _____. A. lines of longitude B. the equator C. continental margins D. aseismic ridges E. mid-oceanic ridges

E

Evidence in support of continental drift includes ____. A. glacial striation patterns B. fossil distribution on different continents C. fit of continental margins D. matching of geologic patterns on continents E. all of the choices are correct

E

Hess's original hypothesis was that sea-floor spreading is driven by deep mantle ____. A. contraction B. spreading centers C. convergent boundaries D. transform faults E. convection

E

Marine geologists can predict the age of igneous rocks of the sea floor by measuring _____. A. the percent of iron-rich minerals in the rock B. their grain size C. the velocity of earthquake waves D. their density E. magnetic anomalies

E

Plumes form ______ that are related to areas of active volcanism such as Iceland, Yellowstone and Hawaii. A. converging plate boundaries B. trenches C. aseismic ridges D. failed rifts E. hot spots

E

The apparent movement of the magnetic poles through geologic time is called _____. A. mantle plume motion B. polar drift C. sea-floor spreading D. continental drift E. polar wandering

E

The most common type of transform faults offset oceanic ____. A. abyssal plains B. microcontinents C. continental shelves D. trenches E. ridge crests

E

The portion of a fracture zone between two offset portions of ridge crest is called a ____. A. normal fault B. strike-slip fault C. convergence zone D. Benioff zone E. transform fault

E