Question 1

At the beginning of which eon of Earth's history did life originate?

Accepted Answer

A)  Proterozoic 
B)  Phanerozoic 
C)  Archean 
D)  Hadean

Question 2

When a sedimentary rock is melted and then re-solidifies it turns into

Accepted Answer

A)  an igneous rock 
B)  a meteorite 
C)  a metamorphic rock 
D)  another sedimentary rock

Question 3

The East African rift zone was formed by

Accepted Answer

A)  two pieces of continental crust separating 
B)  two pieces of oceanic crust colliding 
C)  two pieces of continental crust colliding 
D)  pieces of oceanic and continental crust colliding

Question 4

Isotopic analysis of a rock can tell us

Accepted Answer

A)  what the rock is made of 
B)  the detailed geological history of the rock 
C)  the temperature and pressure conditions under which it formed 
D)  when the rock formed

Question 5

The Hadean Eon corresponds approximately to the

Accepted Answer

A)  last 65 million years of Earth's history 
B)  last 540 million years of Earth's history 
C)  first 600 million years of Earth's history 
D)  first 2 billion years of Earth's history

Question 6

You chemically analyze a small sample of a meteorite. K-40 and Ar-40 are present in a ratio of approximately 1.65 units of K-40 atoms to 8.35 units of gaseous Ar-40 atoms. How old is the meteorite given the half-life of this decay is 1.25 billion years?

Accepted Answer

A)  1.25 billion years 
B)  5.00 billion years 
C)  2.75 billion years 
D)  3.25 billion years

Question 7

Without the greenhouse effect, the oceans on the Earth's surface would

Accepted Answer

A)  have evaporated 
B)  be much the same as they are today 
C)  have covered the entire surface of the Earth 
D)  be frozen

Question 8

Compared to continental crust, oceanic crust is

Accepted Answer

A)  thinner and denser 
B)  thicker and less dense 
C)  thicker and denser 
D)  thinner and less dense

Question 9

Which of the following was NOT a source of heat that helped differentiate the Earth?

Accepted Answer

A)  solar radiation 
B)  impacts 
C)  gravitational potential energy 
D)  radioactive decay

Question 10

The Hawaiian Islands were formed when

Accepted Answer

A)  oceanic crust sank below continental crust at a tectonic plate boundary 
B)  volcanic material flowed out from the interior at a hot spot beneath the Pacific Ocean 
C)  molten lava oozed out between two tectonic plates that were slowly moving apart 
D)  dense material sank while lighter material rose to the surface during the early geological history

Question 11

The carbon dioxide cycle is an example of a

Accepted Answer

A)  negative feedback process 
B)  Milankovitch process 
C)  response process 
D)  neutral feedback process 
E)  positive feedback process

Question 12

In addition to outgassing by volcanoes, another important contributor to the formation the Earth's oceans and atmosphere was

Accepted Answer

A)  impacts by icy planetesimals 
B)  material directly accreted from the Sun 
C)  material directly accreted from the solar nebula 
D)  melting and vaporization of polar glaciers

Question 13

A rock sample contains 1/8 micrograms of the parent radioactive isotope Aluminum-26 and 7/8 micrograms of its daughter isotope Magnesium-40. If the half-life of this decay is approximately 700,000 years, how old is this rock?

Accepted Answer

A)  2.1 million years 
B)  2.8 million years 
C)  1.4 million years 
D)  700,000 years

Question 14

The composition of the early atmosphere was dominated by

Accepted Answer

A)  hydrogen (H2) 
B)  nitrogen (N2) 
C)  carbon dioxide (CO2) 
D)  oxygen (O2)

Question 15

Basalt is a common type of

Accepted Answer

A)  meteoritic rock 
B)  sedimentary rock 
C)  igneous rock 
D)  metamorphic rock

Question 16

Sedimentary rocks subjected to heat and pressure beneath the surface of the Earth (assume no melting occurs) transform into

Accepted Answer

A)  metamorphic rocks 
B)  Meteorites 
C)  other sedimentary rocks 
D)  igneous rocks

Question 17

Which of the following act as greenhouse gases in the Earth's atmosphere?

Accepted Answer

A)  carbon dioxide only 
B)  nitrogen and oxygen 
C)  nitrogen only 
D)  carbon dioxide, water vapor, and methane 
E)  hydrogen only

Question 18

In beta decay,

Accepted Answer

A)  a neutron turns into a proton 
B)  a helium nucleus is ejected 
C)  a proton turns into an electron 
D)  a proton turns into a neutron

Question 19

What do we mean by the "fossil record"?

Accepted Answer

A)  rocks from earlier periods of the Earth's history 
B)  samples of meteorites that fell to Earth early in its history 
C)  remains of ancient organisms preserved in rocks 
D)  an album by the Rolling Stones

Question 20

What do we currently believe was the main source of the Earth's oceans and atmosphere?

Accepted Answer

A)  impacts by icy planetesimals 
B)  outgassing by volcanoes 
C)  material directly accreted from the solar nebula 
D)  melting and vaporization of polar glaciers

Exam 4: The Habitability of Earth