Geology Final Exam

Front 1

The most important concentration of earthquakes by far

Back 1

Circumpacific belt

Front 2

Compressional waves in which the rock vibrates back and forth in the direction of wave propagation

Back 2

P-wave

Front 3

The type of faults generated at the top of the bend as a dense oceanic plate begins to sink down into a trench

Back 3

Normal faults

Front 4

If the measured amplitude of vibration of a rock is 1 cm for a magnitude 4 earthquake then the rocks will move ______ during a magnitude 5 earthquake

Back 4

10cm

Front 5

One suggested cause of deep focus earthquakes

Back 5

Collapse of minerals into denser forms

Front 6

The composition of the upper mantle

Back 6

The ultramafic rock peridotite

Front 7

Rising or sinking of crust requires a _____ mantle

Back 7

Ductile or plastic

Front 8

Seismic wave velocities generally ______ with depth

Back 8

Increase

Front 9

The presence of an S-wave shadow zone implies that the earth's outer core is _______

Back 9

Liquid

Front 10

The rise of the surface of the crust after removal of glacial ice

Back 10

Isostatic rebound

Front 11

Ocean water originated mainly from degassing of ______

Back 11

Earth's interior

Front 12

A deep narrow rift parallel to the crest of a mid-oceanic ridge

Back 12

Sea-floor spreading center

Front 13

Circles of reefs that rim lagoons

Back 13

Atolls

Front 14

This island appears to be an exposed section of the Atlantic mid-oceanic ridge

Back 14

Iceland

Front 15

All rocks on the sea floor are less than _____

Back 15

200 million years old

Front 16

Wegener's theory of continental drift proposed that continents plowed through ______

Back 16

Oceanic crust

Front 17

The downward plunge of cold lithosphere accounts for the existence of ______ as well as their low heat flow

Back 17

Oceanic trenches

Front 18

As a descending plate reaches depths of ______, magma is generated in the overlying atmosphere

Back 18

100 km

Front 19

This supercontinent initially separated into two parts, a northern supercontinent and a southern supercontinent

Back 19

Pangaea

Front 20

The head of large plumes that form "hot spots" may cause uplift and _______

Back 20

Vast fields of flood basalt

Front 21

True or false: Mountain belts are characterized by sedimentary sequences that show little or no deformation

Back 21

False

Front 22

Mountain belts that are young and active are characterized by frequent _________

Back 22

Earthquakes

Front 23

On the North American continent, the ______ mountains extend along the east coast of the U.S.

Back 23

Appalachian Mountains

Front 24

Parts of Alaska originally formed south of the ________ and moved many thousands of kilometers to become part of the cordillera

Back 24

Equator

Front 25

Some accreted terrians were ______, similar to today's New Zealand

Back 25

Micro continents

Front 26

The higher content of _______ in coal, the more combustible (economically desirable) it is

Back 26

Carbon

Front 27

Common oil traps are created by ________

Back 27

Anticlines and domes

Front 28

_________ is derived from dense plant vegetation that grew in swamps

Back 28

Coal

Front 29

Naturally occurring materials that can be mined profitable are referred to as _________

Back 29

Ores

Front 30

True or false: Aluminum ore is the product of direct chemical precipitation from sea water

Back 30

False

Front 31

A _______ is a seismic sea wave

Back 31

Tsunami

Front 32

The first wave to arrive at a recording station following an earthquake

Back 32

P-wave

Front 33

The most famous example of a right-lateral transform fault

Back 33

San Andreas Fault

Front 34

The minimum number of stations needed to determine the location of an earthquake epicenter

Back 34

Three

Front 35

Richter scale values above 7 are not accurate. The ________ scale is a more objective method of measuring the energy of a large earthquake

Back 35

Moment magnitude

Front 36

As lava cools below the _______ point, a record of the earth's magnetic field is permanently trapped in the rock

Back 36

Curie point

Front 37

A cavity (cave) or body of low-density material causes a _______ pull on a gravity meter relative to average crust

Back 37

Weaker

Front 38

The P-wave shadow zone can be explained by the refraction of P-waves at the _____ boundary

Back 38

Core-mantle

Front 39

The earth's magnetic field is created by electric currents in this layer of the earth

Back 39

Liquid outer core

Front 40

The return of some of the energy of a seismic wave to the earth's surface after it bounces off a rock boundary

Back 40

Seismic reflection

Front 41

Margins found on the edges of most of the landmasses bordering the Atlantic ocean

Back 41

Passive

Front 42

True or false: Oceanic crust is very similar to continental crust

Back 42

False

Front 43

The flattest features on earth

Back 43

Abyssal plains

Front 44

Most seamounts are _________

Back 44

Extinct volcanoes

Front 45

A great mass of sediment-laden water that is pulled downward by gravity along the continental slope

Back 45

Turbidity current

Front 46

Yellowstone, Iceland, and Hawaii are areas of active volcanism related to plumes and are called ___________

Back 46

"Hot spots"

Front 47

True or false: In the Paleozoic Era the North American continent grew westward because of the accumulation of the Cordillera

Back 47

False

Front 48

Rocks of the crust and the uppermost mantle make up this layer of the earth

Back 48

Lithosphere

Front 49

Mid-oceanic ridges on the sea floor are associated with this type of tectonic boundary

Back 49

Divergent

Front 50

Seafloor spreading implies that seafloor rocks should be _________ on the crest of the mid-ocean ridges

Back 50

Youngest

Front 51

The region of a continent that has been structurally stable for a prolonged period of time

Back 51

Craton

Front 52

Most bodies of ultramafic rock are regarded as _______ material that has been faulted into the crust during orogeny

Back 52

Mantle material

Front 53

Of the two major mountain belts in Northern America, the western mountains are called _________

Back 53

The North American Cordillera

Front 54

The Himalayan Mountains formed as the result of __________ convergence

Back 54

Continent-continent

Front 55

Major mountain belts with higher mountain ranges tend to be geologically _________ relative to those where the mountains are lower

Back 55

Younger

Front 56

Streams concentrate heavy minerals into these economic ore deposits

Back 56

Placer deposits

Front 57

True or false: Because natural gas is denser than oil it accumulates on the bottom of the oil

Back 57

False

Front 58

Hydrothermal fluids are the most important source of _______ ore deposits

Back 58

Metallic

Front 59

Hydrocarbons must be ________ to break down into simpler molecules useful to humans

Back 59

Heated

Front 60

Most of the easily recoverable uranium in the U.S. is found in this type of rock in New Mexico, Utah, and Colorado

Back 60

Sandstone

Front 61

List three geophysical properties that change greatly at the boundary between the core and mantle

Back 61

Seismic velocity, density, temperature