Fossils B/C

[bernard]

Question Marathons Explained

[BennyTheJett]

A piece of bone was found in South Dakota, and was analyzed to determine the age of the bone. A mass spectrometer revealed that the amount of C-14 was 6.25%.

How many half lives have passed?

Given that 1 half life of Carbon-14 is 5730 years, how long ago did the creature die?

While Carbon-14 dating is generally very accurate, list two of its limitations.

For older specimens, Potassium-40 is often used. Give the half life of Potassium-40, and the decay product.

In what US State is the Mazon Creek lagerstatte found?

About how thick is Beecher’s Trilobite Bed?

Which of the lagerstatte on the fossils rule sheet contains evidence that the area the lagerstatte was located in was once at the bottom of a lake?

[rlin2009]

Click to Show Answer

 
1. 4 half-lives have passed.
2. This creature will have died around 22,920 years ago
3. It is only able to determine samples that are up to 50,000 years old since those older than that lack enough carbon-14 to be detected. Additionally, samples can be contaminated by other carbon-containing materials. 
4. The half-life of Potassium-40 is 1.28*10^9 years and the decay product is calcium-40 89% of the time and argon-40 11%.
5. The Mazon Creek lagerstatte can be found in Illinois. 
6. It is around 3-4 cm or 1.2-1.6 in. thick.
7. The Green River Formation as the make-up of the sediments show that as time went on, large amounts of sand, silt, and mud flowed in from other streams. 

Which phorusrhacid is the only one known to have migrated from South America during the Great American Exchange?

[treesdea]

nvm

[stlcards422]

Click to Show Answer

 
1. 4 half-lives have passed.
2. This creature will have died around 22,920 years ago
3. It is only able to determine samples that are up to 50,000 years old since those older than that lack enough carbon-14 to be detected. Additionally, samples can be contaminated by other carbon-containing materials. 
4. The half-life of Potassium-40 is 1.28*10^9 years and the decay product is calcium-40 89% of the time and argon-40 11%.
5. The Mazon Creek lagerstatte can be found in Illinois. 
6. It is around 3-4 cm or 1.2-1.6 in. thick.
7. The Green River Formation as the make-up of the sediments show that as time went on, large amounts of sand, silt, and mud flowed in from other streams. 

Which phorusrhacid is the only one known to have migrated from South America during the Great American Exchange?

Click to Show Answer

titanis

1: Identify
2: What time period did they live>?
3: What are their closest living relatives?