Absolute dating methods

Question 1

List the 5 dating methods:

Answer 1

• radio carbon dating (carbon 14)
• dendrochronology
• thermoluminescence
• potassium-argon
• pollen analysis

Question 2

What does carbon 14 measure and how long does it take for it to drop to half its former level?

Answer 2

measures disintegration of carbon molecules in organic matter, ie. anything that has lived
if cross referenced with other methods=more reliable
takes 5730 yrs for half

Question 3

What can the method of carbon 14 be used on?

Answer 3

animal/plant remains eg charcoal, bones, leather, cloth

dated up to 70 000 yrs old

Question 4

Dendrochronology?

Answer 4

• uses tree rings to date trees and objects made of wood and is precise.
• new ring each year
• thickness of rings subject to seasonal variations
• arch. created master chart of tree ring growth to help

Question 5

Thermoluminescence dates?

Answer 5

date inorganic material and ceramic artefacts, eg. pottery, potsherds, silt, quartz, flint, any baked objects
date up to 200 000 yrs old

Question 6

how does thermoluminescence work?

Answer 6

mineral crystals store energy which is released by heat.

by heating the artefacts and measuring amount of energy released, time elapsed since last fired can be calculated

Question 7

Potassium-Argon dates?

Answer 7

date volcanic rocks

decay slowly, date over 1 000 000 yrs

Question 8

How does Potassium-Argon work?

Answer 8

argon gas remaining as potassium in rock decays at fixed rate and measured to determine age of rock

Question 9

Pollen Analysis?

Answer 9

useful in bogs and marshes where pollen grains shed by tree/plants will survive for thousand of yrs
can give rough outline of vegetation of area in past and proportions of species of trees in nearby woodlands