Chapter 3 (part 2)

Question 1

The geologic time scale is divided into a number of types of units of differing size. From the largest units to the smaller units, they are:

Answer 1

• Eons
• Eras
• Periods
• Epochs

Question 2

List 5 Chronostratigraphic units:

Answer 2

• Eonothem
• Erathem
• System
• Series
• Stage

Question 3

In order from oldest to youngest, the three Eons are:

Answer 3

• Archean
• Proterozoic
• Phanerozoic

Question 4

In order from oldest to youngest, the three eras are:

Answer 4

• Paleozoic
• Mesozoic
• Cenozoic

Question 5

List the Periods of the Mesozoic Era:

Answer 5

• Cretaceous
• Jurassic
• Triassic

Question 6

List the Periods of the Cenozoic Era:

Answer 6

• Neogene
• Paleogene

Question 7

List the Epochs of the Cenozoic Era:

Answer 7

^{Neogene Period}
• Holocene
• Pleistocene
• Pliocene
• Miocene

^{<u>Paleogene Period</u>}
• Oligocene
• Eocene
• Paleocene

Question 8

List the Periods of the Paleozoic Era:

Answer 8

• Permian
• Carboniferous
• Devonian
• Silurian
• Ordovician
• Cambrian

Question 9

The structure of the atom consists of:

Answer 9

• Nucleus
• Electrons

• Various subatomic particles

Question 10

What happens when atoms decay?

Answer 10

• Radioactive decay occurs by releasing subatomic particles and energy.
• The radioactive parent element is unstable and undergoes radioactive decay to form astable daughter element.

^{<em>Example: Uranium, the parent element, undergoes radioactive decay, releases subatomicparticles and energy, and ultimately decays to form the stable daughter element, lead.</em>}

Question 11

The rate of decay is not affected by changes in the following:

Answer 11

• Pressure
• Temperature

• Other Chemicals

Question 12

Potassium-40 is found in these minerals:

Answer 12

• Potassium feldspar
• Muscovite
• Amphibole
• Glauconite

Question 13

Uranium may be found in:

Answer 13

• Zircon
• Uraninite
• Monazite
• Apatite
• Sphene

Question 14

Why are Earth Rocks Younger than Meteorites and Moon Rocks?

Answer 14

• The Earth is geologically active. The older rocks may have been eroded away.
• Older rocks may have been deeply buried under sedimentary rocks, or beneath thrustsheets.
• Older rocks may have been heated, metamorphosed, or melted, and their dates “reset”to the time of heating, metamorphism, or melting.