Dating Techniques

Question 1

Law of superposition (stratigraphy)

Answer 1

In any undisturbed sequence of rock layers, the oldest layer is at the bottom, and the layers become progressively younger toward the top.

Old at bottom, young at top

Question 2

Biostratigraphy

Answer 2

a branch of stratigraphy that uses fossil organisms to date and correlate rock layers

Uses fossils in rocks to date and correlate rock layers

Question 3

Radiometric Dating

Answer 3

• a method used to determine the absolute age of rocks and fossils through the decay of radioactive isotopes.
• It measures the ratio of parent isotopes to daughter isotopes within a sample.
• Common methods include carbon-14 dating for organic materials, and uranium-lead, potassium-argon, and rubidium-strontium dating for rocks and minerals.
• This technique provides precise age estimates, often in millions or billions of years.

ratio of parent to daughter isotopes sealed within sample, carbon 14,

Precise

Question 4

Use of law of supersuperposition

Answer 4

Useful for relative dating of sedimentary rock layers. It provides a framework for understanding the sequence of geological events.

helps sequence geological events

Question 5

Biostratigraphy

Answer 5

Combines with other methods to refine the dating of layers. It helps identify the relative ages based on fossil content.

Question 6

Use of Radiometric Dating

Answer 6

Offers absolute ages, which can calibrate relative dating methods. It is crucial for determining the age of rocks and fossils beyond the range of other techniques.

Absolute datesx bn7

Question 7

What is ABSOLUTE dating?

How is it different to relative?

Answer 7

Definition: Absolute dating determines the exact age of an artifact, rock, or fossil in years.
Example: Radiometric dating, such as using carbon-14 to date a piece of ancient wood, which might be found to be 5,000 years old.

Question 8

What is RELATIVE dating?

Difference to absolute?

Answer 8

Definition: Relative dating establishes the order of events without determining their exact age.
Example: The law of superposition allows geologists to say that a particular layer of rock is older than the layer above it but does not provide an exact age for either layer.