Geological time

Question 1

Explain the principle of superposition

Answer 1

• Each layer must be younger than the one below
• Layer at the bottom is therefore oldest and vice-versa
• If beds are titled, occurred after deposition

Question 2

Explain the principal of continuity

Answer 2

• Sediments accumulate in continuous sheets

- If cut by a valley, used to span it and was cut by a river in the valley

Question 3

Name the 4 eons, what are the first 3 known as?

Answer 3

Hadean,archaen,proterozoic, and phanerozoic. The first 3 are known as the pre-Cambrian era/pre-phanerozoic eon.

Question 4

Name the 3 eras.

Answer 4

Palaeozoic, Mesozoic, Cainozoic.

Question 5

True/False, fossils are rare during the pre-Cambrian era.

Answer 5

True.

Question 6

How did Da Vinci calculate the age of the earth and how old did he predict?

Answer 6

Measured rate of sedimentation on Po delta.

200,00 years old.

Question 7

How did Ussher predict the age of the earth and how old did he predict?

Answer 7

Used biblical texts to find number of generations since Adam, found 6000 years old.

Question 8

How did Buffon predict age of the earth and how old?

Answer 8

measured rate of cannon ball cooling and scaled to earth.

About 75,000 years old.

Question 9

Why was Hutton a mad lad?

Answer 9

He basically said all geological processes take a fuck ton of time, so it must exceed 6000 years old you bible basher.

Question 10

Why was Kelvin even madder than Hutton?

Answer 10

Mate he thought the earth was molten, measured how long it would take to cool to todays temp. Mad innit? Well he predicted 30-400 million years, but then changed to 30-40 million years or if you’re fucking fancy then 30-40 Ma.

Question 11

Principle of uniformitarianism

Answer 11

Physical processes observed today happened in the past, so earth must be fucking old as these processes are slow.

Question 12

What did Darwin do?

Answer 12

At least 300Ma, erosion of Downs.

Question 13

What is the difference between relative age and absolute age?

Answer 13

Relative age is the age relative to something else, whilst absolute age is age from the beginning.

Question 14

What does Holmes and Patterson use as a way of gathering age? What did they predict?

Answer 14

Uranium dating-3300Ma

Iron dating of meteorite-4560Ma

Question 15

What were the big 5 extinction events? What was the biggest?

Answer 15

End Cretaceous,End Triassic,end Permian, Late Devonian and End Ordovician.
Permian event- 96% marine and 70% terrestrial, 10 million years recovery!

Question 16

Explain the difference between P- and S- waves.

Answer 16

Both travel in the solid of the earth, both travel through solids but only P through liquids.
P are compressional body waves.
S shear body waves.