Monday, November 24, 2008

Underwater volcanoes are now a hot topic

Geologist Dr. Mark Hannington didn't think he would see ocean floor mining in his lifetime.
"I honestly never thought this would happen," he said. "But it's going to and it's quite incredible."
Mark Hannington addresses questions from the audience at the 2008 Geoscience Forum after his presentation on ocean floor volcanoes.

Hannington, a geology professor, researcher and fifth editor of the international research journal Economic Geology, gave a presentation Tuesday evening titled "Exploring Active Volcanoes on the Ocean Floor" to more than 80 people at the legislative assembly's Great Hall. The presentation was part of the 2008 Geoscience Forum being held in Yellowknife this week.

Hannington's presentation focused on underwater volcanic activity and the significance it has to mineral deposits forming on the ocean floor.

"Eighty per cent of all volcanoes on Earth are underwater," he said. "There are about 1,500 active volcanoes on land and some 15,000 to 20,000 underwater younger than 190 years old."

Created by satellite imaging, the map they use of the ocean floor is a model based on gravity and isn't an actual topographic map, but is the best available map of the ocean floor.

"By measuring deflections in the sea surface, basically bumps on the surface of the ocean you could calculate a gravitation effect of something sitting on the ocean floor," he explained.

Hannington explained how "black smokers", or sea vents, produce metals on the ocean floor. A black smoker is a type of hydrothermal vent found on the ocean floor. The vent is formed from superheated water from below the crust of the Earth coming through the ocean floor. The water is rich in dissolved minerals from the crust, most notably sulfides. When it comes in contact with cold ocean water, many minerals precipitate, forming a black chimney-like structure around each vent. The metal sulfides that are deposited can become sulphide ore deposits.

"It creates mining opportunities. The only thing is would it be a money making venture or not," said Hannington.

Nautilus Minerals, a mining company, plans to start mining at its Solwara 1 project off the coast of Papua New Guinea in 2010. Seabed mining is something Canadian mining companies might be able to profit from in the future, said Harrington, he said but this is yet to be seen.

"There is a lot of potential benefits but there is also possible environmental effects that could be devastating."

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