Introductory Geology – II (GEOL 1122)

Summer Semester 2023

June 28, 2023

Pre-test 3

Answer all questions. Circle the letter corresponding to the correct answer to each question.

1. Which of the following statements is a correct statement of Uniformitarianism.

a) Present is the key to the future.

b) Present is the key to the past.

c) The past is the key to the future.

d) The past is the key to the present.

2. Considering cross cutting relations, which of the following statements is correct.

a) The rocks cut by a fracture are younger than the fracture.

b) The fracture cutting the rocks is older than the rocks being cut.

c) The fracture cutting the rocks is younger than the rocks being cut.

d) The fracture cutting the rocks is the same age as the rocks themselves.

3. True/False. By Superposition, younger sediments are deposited on older sediments.

a) True.

b) False.

4. The first geologic time scale featured primary, secondary and tertiary rocks. Primary rocks were composed of:

a) sedimentary rock whose clasts were weathered from igneous and metamorphic rock (Hutton).

b) bedrock composed of igneous and metamorphic rock.

c) unconsolidated sediments and soil weathered from sedimentary rock.

5. There are four eons. What is the correct order of Eons from oldest to youngest?

a) Hadean, Archean, Phanerozoic, Proterozoic.

b) Hadean, Archean, Proterozoic, Phanerozoic.

c) Phanerozoic, Hadean, Archean, Proterozoic.

d) Proterozoic, Phanerozoic, Hadean, Archean.

6. Which Eons does not have evidence for life?

a) Archean.

b) Hadean.

c) Phanerozoic.

d) Proterozoic.

7. Which two Eons show evidence microbial life alone?

a) Archean, Phanerozoic.

b) Archean, Hadean.

c) Archean, Proterozoic.

d) Proterozoic, Phanerozoic.

8. Which Eon is the youngest and is subdivided into three eras (Paleozoic, Mesozoic, and Cenozoic)?

a) Archean.

b) Hadean.

c) Phanerozoic.

d) Proterozoic.

9. True/false. The half-life of a radioactive element can change if buried at metamorphic conditions of temperature and pressure.

a) True.

b) False.

10. Consider a rock whose initial number of parent atoms was 1400 atoms. Today there are 175 parent atoms. How many half lifes have elapsed?

a) one.

b) two.

c) three.

d) four.

e) five.

11. If the value of the half-life is 20 million years (20 Ma), then what is the correct age of this rock given the correct answer to question 14?

a) 20 Ma.

b) 40 Ma.

c) 60 Ma.

d) 80 Ma.

e) 100 Ma.