Module 9

Question 1

Learning objective 9.1

describe the Principle of Superposition

Answer 1

rock layers being chronologically stacked

Question 2

Learning objective 9.1

define stratigraphy

Answer 2

the science of using the arrangment and composition of rock layers to interpret geological history

Question 3

Learning objective 9.1

define formation

Answer 3

a large uninterrupted sequence of rock that i made of multiple layers that all share similar properties and all formed under similar conditions

Question 4

Learning objective 9.1

describe radiometric dating

define: isotopes and what rocks are used

Answer 4

a technique to infer the relative age of rock layers
- istopes are used and there are a variant of a chemical element - they undergo radioactive decay
- using a mass spectrometer
igenous rocks are used, esp volanic ash deposits

Question 5

Learning objective 9.3

Describe the Hadean Eon

Answer 5

• named for Hades
• 4.5 billion years ago, young earth collided with a smaller planetoid
• fromed the mood
• oldest rocks dated to be 4.4 billion years old

Question 6

Learning objective 9.3

Describe the Archean Eon

Answer 6

• oldest known fossils; simple celled organiss
• photosynthetic cyanobacteria
• stromatolites - best records of early life

Question 7

Learning objective 9.3

Describe the Proterozoic Eon

Answer 7

• Ediacaran period = larger forms of life evolved, including the first animal life

Question 8

Learning objective 9.3

Phanerozoic Eon: The Paleozoic Era

Cambrian Period