Geology

Question 1

Relative Age

Answer 1

Age rocks compared to other rocks

Question 2

Relative Age Type

Superposition

Answer 2

Layers of sedimentary rock
- Bottom = oldest
- Top = youngest

Question 3

Relative Age Type

Original Horizontality

Answer 3

Rock layers horizontal even if later tilted/curved –> superposition

Question 4

Relative Age Type

Lateral Continuity

Answer 4

Rock layers cont. in all directions even if gap –> superposition

Question 5

Relative Age Type

Inclusions

Answer 5

Small rock inside bigger rock
- Inclusions = older
- Big rock = younger

Question 6

Relatve Age Type

Cross Cutting Relationships

Answer 6

Fault/crack cuts across rock layers = younger than rock layers

Question 7

What clues can tell scientists about the past?

Fossils

Answer 7

• ## Remains ancient living things now in stone

Question 8

What clues can tell scientists about the past?

Mass Extinction

Answer 8

• Many species become extinct short period of time
  Caused by catastrophic events:
• Global Temp. Change
• Asteroid Strike
• Change in Resources
• Volanic Activity

Question 9

How can geologists oragnize rock ages when there are gaps?

Uncomformity

Answer 9

• Gaps/breaks in rock layer caused by erosion, plate tectonics, weathering

Question 10

How can geologists organize rock ages when there are gaps?

Correlate

Answer 10

• Match rock layers on either side of gap based on rock type/fossils

Question 11

How can geologists organize rock ages when there are gaps?

Index Fossil

Answer 11

• Type of fossil
  3 Rules:
• Abundant
• Short period of time (only in few layers)
• Many locations

Question 12

How can geologists organize rock ages when there are gaps?

Key Beds

Answer 12

• Rock layers formed from major event
• Event place –> find relative age of rocks around it