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Clip produced by ArchAnge films for the Sherbrooke Museum of Nature and Science
Narrator: Michel Lamothe, Geologist and Professor at the Université du Québec à Montréal
Date: June 2015
Location: Université du Québec à Montréal
Length: 2:23

Optically stimulated luminescence is an absolute dating method that has been revolutionizing the world of archaeology for 30 years. Michel Lamothe, Geologist and Professor at the Université du Québec à Montréal, tells us about the contribution of this dating method to the understanding of Eastern Townships’ history.

On-screen: Close-up image of a man standing in a laboratory.

[Michel Lamothe] My name is Michel Lamothe. I am a geologist, which means I’m interested in the history of the earth and the earth sciences and such. I’m also what we call a geomorphologist. I’m interested in the landscape and what it tells us about the history of glaciation and, it that sense, we’re pretty close to what need the archeologists who want to know what is happening when the ice sheet is melting, for instance. But I’m also a geochronologist. I have developed over the last twenty years a method called luminescence, which is a dating method that is sort of now pushing aside the need for radio-carbon dating.

On-screen text: A tool for archaeologists

[M.L.] Luminescence dating can take relatively precisely the moment that a piece has been fabricated by men if it involved heating, like ceramic. Luminescence dating is also useful to know the age of a sediment that will bury a piece that would have been made by men, like a flint for instance. So luminescence dating has been very, very useful and basically rewriting the history of men over the last twenty years.

On-screen text: An example

[M.L.] The age that we obtain using luminescence at the Cliche-Rancourt site is 12 000 years old. This confirms the antiquity of the pieces that were retrieved by the archeologists and also it confirms that, at the same time, there was still large pieces of the Laurentide ice sheet over southern Quebec, not very far from the site which is about 100 km north.

On-screen text: An anecdote

[M.L.] My archeologist friends are very keen to know quite precisely the age of a site. Actually, we wonder sometimes if we would like to know at what time the men arrived at one site, which is pretty impossible for us. But sometimes also on the other hand, it’s very difficult to get one piece, two pieces or three pieces out of about 10 000 pieces at one site. So, there’s a lot of debate! But archeologists are really nice people and it’s very exciting to work with them.