Methods of dating fossils (1)

Question 1

How old is the Earth?

Answer 1

4.6 Million Years.

Question 2

Why do you need to date fossils?

Answer 2

To make sense of the variety of fossils found in various layers of rock.

Question 3

What are the types of indirect dating? (4)

Answer 3

• Relative dating
• Paleomagnetic dating
• Fauna comparisons
• Dendrochronological comparisons

Question 4

What are the types of direct dating?

Answer 4

-Radiometric dating

Question 5

What is relative dating?

Answer 5

Relative dating is used to arrange geological events, and the rocks they leave behind, in a sequence. The method of reading the order is called stratigraphy (layers of rock are called strata). Relative dating does not provide actual numerical dates for the rocks.

Question 6

Briefly explain the concept of relative dating.

Answer 6

-Rock layers below where the
fossil is found will be older
-Layers above = younger
-Ages are relative to one
another

Question 7

What is radiometric dating?

Answer 7

Radiometric dating is used to estimate the age of rocks and other objects based on the fixed decay rate of radioactive isotopes. It is an absolute method.

Question 8

Briefly explain the concept of radiometric dating. (4)

Answer 8

• Rocks contain radioactive isotopes of certain elements
• These decay at a constant rate
• Age of rocks is used by comparing the ratio of radioactive isotopes and their stable forms
• Different isotopes are used to date different types of rock and fossils

Question 9

The mineral _____ and type of fossil determine the method used

Answer 9

Contents

Question 10

How do we measure radiometric dating?

Answer 10

• Radiometric dating measures in millions of years
• Millions of years (my)
• Millions of years ago (mya)

Question 11

What is paleomagnetism?

Answer 11

Paleomagnetism is the study of magnetic rocks and sediments to record the history of the magnetic field. Some rocks and materials contain minerals that respond to the magnetic field.

Question 12

What is dendrochronological comparison dating?

Answer 12

Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood.

Question 13

What is fauna comparison dating?

Answer 13

The method of dating by which a fossil of an animal is examined and compared with remains of other animals (which have already been dated) to see which animal resonates the most with the fossil found, in order to see which time period it came from.