Alien Impact Poisons Canadian Town

"The impact changed the grain size," said Leybourne.

It's basically the same difference as having a few large blocks of salt in water compared to pulverized salt in water -- which dissolves far more readily and makes the water far saltier.

Some other similar effects have been seen at other impact sites around the world, said Richard Grieve, Chief Scientist of Natural Resources Canada's Earth Sciences Sector, which includes the Canadian Geological Survey. Grieve is an expert on impact geology but not a co-author on the Geology paper.

"They are a huge agent for change," Grieve told Discovery News, regarding how meteor impacts affect local geology.

Impact craters elsewhere have previously been blamed for tinkering with the flows of water or hydrocarbons.

A good example, Grieve says, is the gigantic Chicxulub Crater, which intersects part of the Yucatan Peninsula in Mexico. The geological structures created by that 65-million-year-old impact channel water away from the city of Merida, home to almost a million people.

"That's bad news for the people who live in the crater," said Grieve. "They have a water problem."

But now that they understand the geological cause of the problem, they can work out a solution, he said. And since the 175 known impact structures on Earth all overwhelm the local geology in similar ways, what applies at one crater can often apply to others.
 

Related Links:

Larry O'Hanlon's blog: Earth Matters

NASA images of the Chicxulub Crater

The Canadian Geological Survey

How Stuff Works: 10 Memorable Meteor Crashes