Geology Exam 1

Front 1

From choices below, the best estimate of the age of the Universe is ____________ old.
a. 5 million
b. 6 billion
c. 14 billion
d. 100 billion

Back 1

14 billion years

Front 2

Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant galaxies appears to be ____________.
a. red shifted
b. blue shifted
c. green shifted
d. none of the above

Back 2

red shifted

Front 3

Atoms that are heavier than iron are generally produced by ____________.
a. fission reactions within stars
b. fusion reactions within stars
c. explosion of supernovas
d. the Big Bang

Back 3

explosion of supernovas

Front 4

Chemically, the Moon is quite similar to ____________.
a. sea water
b. Earth’s crust
c. Earth’s mantle
d. Earth’s core

Back 4

Earth’s mantle

Front 5

Differentiation of the core from the mantle early in Earth’s history was possible because the planet was ____________ at the time.
a. very cold
b. very hot
c. very small
d. the only planet in the Solar System

Back 5

very hot

Front 6

Heat transfer that occurs through the movement of a fluid, driven by temperature differences within the fluid, is called ____________.
a. radiation
b. conduction
c. convection
d. adhesion

Back 6

convection

Front 7

In the whole Earth, the four most common elements are oxygen, silicon, magnesium, and ____________.
a. copper
b. lead
c. iron
d. zinc

Back 7

iron

Front 8

The most common minerals within Earth are ____________.
a. silicates
b. carbonates
c. oxides
d. hydroxides

Back 8

silicates

Front 9

Earth’s magnetic field is generated by ____________.
a. the flow of the liquid inner core
b. the flow of the liquid outer core
c. the convective flow of the mantle
d. magnetic minerals within the crust

Back 9

the flow of the liquid outer core

Front 10

10.The densest layer of Earth is the ____________.
a. crust
b. mantle
c. outer core
d. inner core

Back 10

inner core

Front 11

TThe distinction between the crust and mantle is primarily on the basis of a difference in ____________; the distinction between the lithosphere and asthenosphere is primarily on the basis of a difference in ____________.
a. chemistry (mineral content); degree of physical rigidity
b. color; chemistry (mineral content)
c. degree of physical rigidity; chemistry (mineral content)
d. chemistry (mineral content); chemistry as well

Back 11

chemistry (mineral content); degree of physical rigidity

Front 12

The lithosphere is composed of the ____________.
a. crust only
b. crust, mantle, and outer core
c. top 100 m of sediments and sedimentary rocks
d. crust and the uppermost part of the mantle

Back 12

crust and the uppermost part of the mantle

Front 13

The two most common elements in the crust of Earth are ____________.
a. iron and calcium
b. magnesium and manganese
c. oxygen and hydrogen
d. oxygen and silicon

Back 13

oxygen and silicon

Front 14

Marine magnetic anomaly belts (the magnetic “stripes” on the ocean floor) are widest when and where ____________.
a. continents are joined to form supercontinents
b. sea-floor spreading rates are relatively rapid
c. sea-floor spreading rates are relatively slow

Back 14

sea-floor spreading rates are relatively slow

Front 15

Wegener’s evidence for continental drift was so compelling that virtually all geologists agreed with the idea of continental drift when he first proposed his idea.
a. true
b. false

Back 15

false

Front 16

The oldest ocean crust is about ____________ years old.
a. 50 thousand
b. 4 billion
c. 200 million
d. 2.5 million

Back 16

200 million

Front 17

Under the theory of plate tectonics, the plates themselves are ____________.
a. discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another
b. discrete layers of lithosphere that are vertically stacked one atop the other
c. composed only of continental rocks, which plow through the weaker oceanic rocks
d. very thick (approximately one-quarter of Earth’s radius)

Back 17

discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another

Front 18

Within the terminology of plate tectonics, an active margin is ____________.
a. synonymous with “subduction zone”
b. a 5 mile radius surrounding an active volcano
c. a continental coastline that coincides with a plate boundary
d. anywhere on Earth where earthquakes are especially frequent

Back 18

a continental coastline that coincides with a plate boundary

Front 19

Tectonic plates move at rates that are approximately ____________.
a. 1 to 5 cm every 1,000 years
b. 1 to 15 cm/year
c. 1 to 15 m/year
d. 10 to 100 m/year

Back 19

1 to 15 cm/year

Front 20

Mid-ocean ridges are ____________.
a. convergent plate boundaries
b. divergent plate boundaries
c. transform plate boundaries

Back 20

divergent plate boundaries

Front 21

As compared to a slowly spreading mid-ocean ridge, a rapidly spreading ridge is ____________.
a. wider
b. narrower
c. more felsic in lava composition

Back 21

wider

Front 22

At a subduction zone, the downgoing (subducting) plate ____________.
a. is always composed of continental lithosphere
b. is always composed of oceanic lithosphere
c. may be composed or either oceanic or continental lithosphere

Back 22

is always composed of oceanic lithosphere

Front 23

23.Hot spots are caused by ____________.
a. friction due to the lithosphere sliding atop the asthenosphere
b. unusually dense concentrations of radioactive isotopes at various points in the crust
c. hot plumes of mantle material that rises up through cooler, denser surrounding rock
d. factors that remain completely unknown at this time

Back 23

hot plumes of mantle material that rises up through cooler, denser surrounding rock

Front 24

The San Andreas Fault Zone in southern California is an example of a ____________ plate boundary.
a. convergent
b. divergent
c. transform

Back 24

transform

Front 25

The silicate tetrahedron that forms the building block of all the silicate minerals is composed of silicon and what other element?
a. magnesium
b. oxygen
c. iron
d. carbon

Back 25

oxygen

Front 26

Minerals are classified into groups primarily on a basis of ____________.
a. chemistry, specifically the cations within the chemical formula
b. chemistry, specifically the anions within the chemical formula
c. hardness; hard, soft, and medium are the three primary classes
d. number of cleavage directions present

Back 26

chemistry, specifically the anions within the chemical formula

Front 27

The difference between lava and magma is that ____________.
a. magma is light in color and lava is dark
b. magma usually has mafic composition and lava usually has felsic composition
c. magma is found beneath the Earth’s surface, whereas lava has reached the surface
d. magma flows more quickly than lava

Back 27

magma is found beneath the Earth’s surface, whereas lava has reached the surface

Front 28

When magma crystallizes, ____________ are formed.
a. intrusive igneous rocks
b. extrusive igneous rocks
c. volatiles
d. pyroclastic debris

Back 28

intrusive igneous rocks

Front 29

The formation of magma within Earth is not caused by which of the following processes?
a. decompression (drop in pressure)
b. addition of water
c. transfer of heat from adjacent magma or very hot rocks
d. loss of water to the atmosphere

Back 29

loss of water to the atmosphere

Front 30

As compared to coarse-grained igneous rocks, all fine-grained igneous rocks ____________.
a. cool and solidify more quickly
b. cool and solidify more slowly
c. solidify at higher temperatures
d. solidify at lower temperatures

Back 30

cool and solidify more quickly

Front 31

Coarse-grained granite is most similar in chemical and mineral composition to fine-grained ____________.
a. andesite
b. basalt
c. komatiite
d. rhyolite

Back 31

rhyolite

Front 32

Coarse-grained gabbro is most similar in chemical and mineral composition to fine-grained ____________.
a. andesite
b. basalt
c. komatiite
d. rhyolite

Back 32

basalt

Front 33

Most commonly, felsic igneous rocks ____________.
a. contain more iron and magnesium than intermediate rocks
b. are lighter in color than mafic rocks
c. are darker in color than mafic rocks
d. are found in oceanic crust

Back 33

are lighter in color than mafic rocks

Front 34

About how long after the Big Bang did the first elements form?
a. 3 seconds
b. 10 years
c. 300,000 years
d. 3 billion years

Back 34

3 seconds

Front 35

You are standing on top of a volcano located at a convergent plate boundary on continental crust. Which two minerals are most likely to be in the rocks below your feet?
a. quartz, muscovite
b. olivine, Ca-rich plagioclase
c. amphibole, biotite
d. olivine, quartz

Back 35

amphibole, biotite

Front 36

The mineral orthoclase has the following formula - K(AlSi3)O8. What kind of silicate structure does orthoclase have?
a. framework
b. single chain
c. sheet
d. double chain

Back 36

framework

Front 37

Which of the following statements is true?
a. a scientific theory is consistent with many observations and has passed many tests.
b. scientific theories can be quite speculative and may fail to explain many observations related to the theory.
c. there is no real difference between a scientific theory and a scientific hypothesis.
d. scientific theories can be proven true after years of testing.

Back 37

a scientific theory is consistent with many observations and has passed many tests.

Front 38

As the solar nebula cooled the planets began to condense out of the swirling disk of material that surrounded the Sun. Which of the following statements is true?
a. Elements and compounds which melt and vaporize at low temperatures tended to remain nearest the Sun, which was very hot.
b. Elements and compounds which melt at high temperatures and are usually solid tended to remain in the cold, outer parts of the solar nebula
c. The compounds that make up the terrestrial planets have higher melting temperatures than the compounds that make up the giant planets.
d. Compounds such as iron and magnesium oxide are common in the planets Neptune and Pluto.

Back 38

The compounds that make up the terrestrial planets have higher melting temperatures than the compounds that make up the giant planets.

Front 39

The mineral augite has the chemical formula Ca(Mg,Fe)(Al,Si) 2O6. This mineral has which kind of silicate structure?
a. single chain
b. double chain
c. sheet
d. twin

Back 39

single chain

Front 40

The Andes Mountains of South America are a result of which type of plate boundary?
a. convergent
b. divergent
c. transform
d. mid-ocean ridge

Back 40

convergent