WOW! An 800-million year old fossil. The oldest on so far!
http://www.cbc.ca/news/technology/story/2011/06/13/science-yukon-fossil-biomineralization.html
Direct Exert from Article : http://www.cbc.ca/news/technology/story/2011/06/13/science-yukon-fossil-biomineralization.html
http://www.cbc.ca/news/technology/story/2011/06/13/science-yukon-fossil-biomineralization.html
Direct Exert from Article : http://www.cbc.ca/news/technology/story/2011/06/13/science-yukon-fossil-biomineralization.html
Phoebe Cohen was awestruck when she first looked through a high-powered electron microscope at a rock sample hammered out of the wilderness of the Yukon. What she saw was 800 million-year-old fossilized evidence that organisms were trying to protect themselves by forming their own shield-like plates.
It is the oldest evidence ever of biomineralization, the use of minerals by a living thing to form a hard shell, similar to the way clams or lobsters form their own protection. The tiny fossils date back between 717 and 812 million years.
"It's just amazing to think about the fact that I'm the first person to ever see this specimen in the whole history of humanity," Cohen said with a laugh in a telephone interview. "It makes all of the other hard work and drudgery definitely worth it."
The drudgery started in June 2007 when she and fellow Harvard University PhD student, Francis Macdonald, travelled to Eagle, Alaska, a remote community on the Yukon River along the U.S.-Canada border.
The pair took a helicopter across the border into the Canadian territory and camped while they gathered ancient carbonate rock samples in an area of that had once been the floor of a shallow ocean.
A persistent grizzly bear forced them to cut their search short by about 10 days.
"There were two of us and only one gun," she recalled. "I was holding a can of bear spray."
But by then the pair had gathered enough samples for their research.
Cohen, Macdonald and their co-authors report their findings in this month's edition of the journal Geology.
Breaks record by 250 million years
Until now the oldest evidence from similar organisms biomineralizing was found in Africa and dates back to about 550 million years ago, Cohen said.
The fossil was found among ancient carbonate rock samples in an area of the Yukon that had once been the floor of a shallow ocean. Courtesy of Phoebe Cohen and Francis Macdonald/MIT Living things started biomineralizing for protection from being eaten and the creation of the shield-like plates from these single-celled organism may be no different.
"In the case of these little fossils from the Yukon, we're not quite sure what they were being used for," she said. "But it was probably a combination of protection and also enabling the organisms to stay up in the water column."
The fossil isn't visible with the naked eye, at just 10 to 40 microns in size it's about one-fifth the circumference of a human hair.
After using a mild acid on the soft rock to etch away the carbonate from the fossils, Cohen saw hundreds of the tiny creatures with the honeycomb-like plates of armour.
"It was the most amazing thing in the world," she recalled.
The discovery is what she and her partners believe to be the first "slam dunk" evidence ever for active biomineralization.
And while the fossils have never been found anywhere else in the world, Cohen theorizes that it's because researchers didn't know they should be looking for something so small.
She predicted it won't be long before more of such fossils are discovered.
"That's one of the exciting things about publishing this article. We all build on previous knowledge."
Cohen used part of the research for her Harvard thesis and is now the education and outreach lead at the Massachusetts Institute of Technology's NASA Astrobiology Team in Cambridge, Mass.
Macdonald also used some of the research in his thesis and is now an assistant professor of geology at Harvard.
"It ended up being a really rich and fruitful area for us to research on this time period in our history," she said.
"(Canadians) have great fossils," she added with a laugh.
It is the oldest evidence ever of biomineralization, the use of minerals by a living thing to form a hard shell, similar to the way clams or lobsters form their own protection. The tiny fossils date back between 717 and 812 million years.
"It's just amazing to think about the fact that I'm the first person to ever see this specimen in the whole history of humanity," Cohen said with a laugh in a telephone interview. "It makes all of the other hard work and drudgery definitely worth it."
The drudgery started in June 2007 when she and fellow Harvard University PhD student, Francis Macdonald, travelled to Eagle, Alaska, a remote community on the Yukon River along the U.S.-Canada border.
The pair took a helicopter across the border into the Canadian territory and camped while they gathered ancient carbonate rock samples in an area of that had once been the floor of a shallow ocean.
A persistent grizzly bear forced them to cut their search short by about 10 days.
"There were two of us and only one gun," she recalled. "I was holding a can of bear spray."
But by then the pair had gathered enough samples for their research.
Cohen, Macdonald and their co-authors report their findings in this month's edition of the journal Geology.
Breaks record by 250 million years
Until now the oldest evidence from similar organisms biomineralizing was found in Africa and dates back to about 550 million years ago, Cohen said.
"In the case of these little fossils from the Yukon, we're not quite sure what they were being used for," she said. "But it was probably a combination of protection and also enabling the organisms to stay up in the water column."
The fossil isn't visible with the naked eye, at just 10 to 40 microns in size it's about one-fifth the circumference of a human hair.
After using a mild acid on the soft rock to etch away the carbonate from the fossils, Cohen saw hundreds of the tiny creatures with the honeycomb-like plates of armour.
"It was the most amazing thing in the world," she recalled.
The discovery is what she and her partners believe to be the first "slam dunk" evidence ever for active biomineralization.
And while the fossils have never been found anywhere else in the world, Cohen theorizes that it's because researchers didn't know they should be looking for something so small.
She predicted it won't be long before more of such fossils are discovered.
"That's one of the exciting things about publishing this article. We all build on previous knowledge."
Cohen used part of the research for her Harvard thesis and is now the education and outreach lead at the Massachusetts Institute of Technology's NASA Astrobiology Team in Cambridge, Mass.
Macdonald also used some of the research in his thesis and is now an assistant professor of geology at Harvard.
"It ended up being a really rich and fruitful area for us to research on this time period in our history," she said.
"(Canadians) have great fossils," she added with a laugh.
