Dating

Question 1

Relative dating

Answer 1

Uses principles of stratigraphy and the study of fossils to determine the relative ages of rocks, sediments and landforms

Question 2

Absolute dating

Answer 2

Radiometric, isotopic dating were developed to determine the absolute ages

Question 3

What is a isotope and how is it used?

Answer 3

• Isotopes are variants of a particular element.
• Nuclei of a radiotactive isotope can distintergrate, emitting particles, transforming the atom into a atom of a different element
• The original atom is named “parent” and the product “daughter”

Question 4

What are two examples of Isotopic datings?

Answer 4

• 128U is used to date old minerals due to the long half life
• 14C is used for dating newer material due to a shorter halflife

Question 5

Complications of absolute dating?

Answer 5

• The daughter atoms may have been already present
• The sediment may “reset”, caused by heat and pressure

Question 6

Nicolaus Steno

Answer 6

• 1667, he demostrated the preculair tongue stones, found in certain sedimentary rocks were identical to the teeth of modern sharks
• Concluded that they were historical shark teeth

Question 7

Principle of Horizontality

Answer 7

states that sediments are deposited under the influence of gravity as nearly horizontal beds

Question 8

Principle of superposition

Answer 8

states that each layer of a undeformed sedimentary bed is young than the one below

Question 9

William Smith

Answer 9

1793, discovered that you can guess the ages and compare layers according to fossils within