Part D – Isotopic Systems
Using what you learned in the previous section regarding absolute dating, determine the most appropriate methods and the ages of the materials in the following questions.
17. An Archeologist finds some cotton cloth at a burial site and wants to determine the age of the remains. Which isotopic system should they use?
a. Carbon-14 b. Uranium c. Potassium-Argon
18. The Archeologist determines that there is 16.7% of the parent isotope remaining in the cloth sample. How old is the burial site? Hint: you can find the length of the half-life in the reading above.
a. 13,559 years b. 14,798 years c. 16,743 years d. 1.66 billion years e. 1.81 billion years f. 2.05 billion
19. A geologist is trying to date a sequence of sedimentary rocks with abundant fossils and sandstones. Within the sequence is a distinctive clay layer that under closer inspection is fine-grained volcanic ash. Which of the following is the best way to obtain an absolute date for the sequence of rocks?
a. Carbon date the fossils b. Potassium-Argon date the sands c. Uranium date the Zircons in the ash d. Identify the index fossils
20. The geologist determines there is 78.3% of the parent remaining in the sample that they examine. How old is the sequence of rocks? Hint: you can find the length of the half-life in the reading above.
a. 187.5 million years b. 247.8 million years c. 390.7 million years
d. 2.504 billion years e. 1.588 billion years f. 1.202 billion years