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Crustal Gases Studied

Environmental chemists are analysing gases released from deep within the Earth's crust in the hope of learning more about crust composition and formation.

The gases are being trapped and sampled in deep salty lakes in the Taylor and Wright Valleys of Antarctica. Auckland DSIR scientists Dr Kevin Brown and Dr Jenny Webster have collected samples of carbon dioxide, methane, nitrogen, helium and hydrogen sulphide.

The carbon dioxide and hydrogen sulphide come from bacteria that live in the lower depths of the lakes. Other dissolved gases are released from the earth's crust and diffuse slowly upwards. The project will study the concentration and composition of gases being emitted from the crust as well as from the bacteria.

The high salt content of the lakes means that the water does not circulate and release the gas.

"Because it doesn't convect, any gases that come up through the ground are dissolved in the water and stay there," says Brown. "The lakes are deep, so the pressure of the water makes it easier for the gases to dissolve."

Yvonne Martin, Scott Base