Lab Exam

Question 1

In an anticline, is the rock in the middle at the surface the oldest or youngest?

Answer 1

Oldest

Question 2

In a syncline trough, is the rock in the middle at the surface the oldest or the youngest?

Answer 2

Youngest

Question 3

In an asymmetric anticline, is the rock in the centre the oldest or the youngest?

Answer 3

Oldest

Question 4

In a plunging anticline, is the rock in the centre at the surface the youngest or the oldest?

Answer 4

Oldest

Question 5

In a dome, is the rock at the centre of the surface the youngest or the oldest?

Answer 5

The oldest

Question 6

In a basin, is the rock in the centre at the surface the youngest or the oldest?

Answer 6

The youngest

Question 7

What is a thrust fault most similar to?

Answer 7

A reverse fault

Question 8

Identify these unconformities.

Answer 8

Top left: disconformity

Top right: angular unconformity

Bottom: nonconformity

Question 9

What is this called?

Answer 9

A strike-slip fault.

Question 10

What is a nonconformity?

Answer 10

Sedimentary rock layered on top of igneous or metamorphic rock

Question 11

In a disconformity, what is the separation between the layers called?

Answer 11

A depositional break

Question 12

What is this symbol used to represent?

Answer 12

A plunging anticline

Question 13

What is this symbol used to represent?

Answer 13

A plunging syncline

Question 14

What is this symbol used to represent?

Answer 14

Horizontal bedding

Question 15

What is this symbol used to represent?

Answer 15

Vertical bedding

Question 16

What is the law of superposition?

Answer 16

It states that younger, sedimentary rocks overlie the older ones

Question 17

What does the law of cross cutting relations state?

Answer 17

Intrusive rocks are younger than the rock they cut across or intrude

Question 18

What are index fossils used for?

Answer 18

Can be used to correlate rocks in a separate area

Question 19

Is the law of superposition relative or absolute dating?

Answer 19

Relative

Question 20

Is radiometric dating absolute or relative?

Answer 20

Absolute

Question 21

Are cross-cutting relations relative or absolute in terms of dating?

Answer 21

Relative

Question 22

Is the use of index fossils absolute or relative dating?

Answer 22

Relative

Question 23

What are some common radioactive parent isotopes?

Answer 23

C14, Rb87, K40, U235, U238

Question 24

How is radiometric dating used to obtain the age of a type of rock?

Answer 24

Each radioactive isotope (parent) decays to the daughter isotope at a constant rate, exponentially. The half-life is the time required for half of the parent isotope to decay. After two half-lives, 1/4 remains, after three, 1/8, etc.

Question 25

What is the half-life of carbon? What is the oldest a rock can be for carbon dating to work?

Answer 25

The half-life of carbon is 5570 years. After 50,000 years, all of the radioactive parent isotope has decayed to the daughter isotope (nitrogen). Therefore it does not work because the upper limit of carbon dating has been reached.

Question 26

Is this a marine transgression or regression?

Answer 26

Regression

Question 27

Is this a marine transgression or regression?

Answer 27

Marine transgression

Question 28

Which type of sedimentary rock is the least resistant to weathering? Which is the most?

Answer 28

Least: shale Most: sandstone (more quartzite)

Question 30

What are the five types of sedimentary rocks composed of calcite?

Answer 30

Micrite, coquina, limestone, chalk, travertine.

Question 31

What are the principles of relative stratigraphic dating?

Answer 31

1. Principle of superposition 2. Cross-cutting relations 3. Fossil dating using index fossils

Question 32

What is a principle of absolute dating?

Answer 32

Radiometric dating

Question 33

What is the half-life of carbon?

Answer 33

5570 years