84. Radiocarbon Laboratory (1961)

Radiocarbon Laboratory

The Geological Survey of Canada’s Radiocarbon Dating Laboratory opened in 1961 and continued until 2005. It was one of the many new laboratories set up following the move to the spacious, new Survey headquarters at 601 Booth Street in 1959.

The laboratory determined ages of organic materials by measuring the ratio of radioactive (14C) to stable (12C) carbon isotopes. Radioactive carbon decays over time (with a half-life of 5730 years) into nitrogen. Living plants and animals acquire both forms of carbon, but the radioactive carbon continues to decay when the organism dies. The age of the dead material was determined by measuring the amount of 14C remaining compared to 12C.

In preparation for age-determinations, organic samples were burned in a stream of oxygen and the carbon dioxide (CO2) gas released was purified and stored in compressed-gas cylinders. In its 44 years of operation, the laboratory dated nearly 7000 samples of wood, peat, marine shells, and other materials, dating many events within the last 50 000 years.

The laboratory also determined the effect of nuclear weapons testing on atmospheric 14C concentration by measuring maple leaves from Gatineau Park. The Maple Leaf Project continues today at the University of Ottawa.

Category: Equipment and Instrumentation

Decade: 1960s

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