Ilulissat, Greenland – July 15: Visitors look at the melting of the icebergs collecting ilulissat … [+]
If the catastrophic melting of Greenland has a scientific silver lining, is that climate change can push the long tape of Earth’s life beyond its current threshold 3.7 billion years old.
Greenland’s ice sheet is decreasing as it melts from the warmth of the atmosphere rich in carbon dioxide and more rock is exposed, Paul Bierman, author of “When the ice is gone: what does a Greenland ice core reveal to the shocked land history and the dangerous future“And a geoscientist at the University of Vermont in Burlington, he told me by email.
Nuuk, the largest city of Greenland, sits on the world’s oldest rocks, formed between 3.8 and 3.7 billion years ago, or only 700 million years after Earth itself formed, writes Biermann in his book. Metamorphism heated and squeezed these rocks as the continents of the Earth collapsed together now known as Isa’s supracrustal band, he writes.
Earth’s plate tectonics — which enabled the formation of mountain ranges through the movement of large Korea tiles — Not only did metamorphosis Isa rocks, but also moved those thousands of miles of poleward from which they had formed, marks the Bierman in “when The ice is gone. “
But can they bear evidence of Earth’s earliest life?
The most convincing arguments for ancient life in Greenland remain organic carbon carbon described by Danish geologist minic pink and colleagues in the 1990s, Keyron Hickman-Lewis, a microbial paleontologist at the University of London in the United Kingdom, he told me by email. This carbon is likely a remnant of the ancient biosphere: it has geochemical isotopic characteristics in accordance with biological activity and molecular compositions that suggest they may have received from precursor biomass, notes Hickman-Lewis.
The evidence of ancient life remain controversial
Although different Greenland microfosiles have been proposed over the past 50 years, most of these are more ancient-then have been shown to be non-fossil or later pollution, says Hickman-Lewis.
But there is still hope that thawing can detect signs of the earliest biosphere on Earth.
As the ice withdraws, I think there will be new discoveries, says Hickman-Lewis. That was, after all, the case for the proposed 3.7 billion -year -old stromatolis in Isua, who were identified in an exit that became accessible after the melting of ice, he says.
Stromatolis, sedimentary rock layers, are formed by layers of cyanobacteria, calcium carbonate and blocked sediment.
Although Greenland’s earliest stromatolis are no longer considered compelling evidence of life, we predict that a biosphere existed until the time they formed Isa’s sedimentary rock layers, says Hickman-Lewis. The direct rehearsals of this life can be stored inside, he says.
How difficult is it to confirm microfositiles in Greenland?
For ancient microfosits, more than 3 billion years old, it is very difficult, says Hickman-Lewis. Metamorphism at high temperatures and pressures will degrade organic materials structurally and chemically, which means that traces of life in Greenland can be very difficult to detect, and even more difficult to confirmed, he says.
Microfosiles are rare, even in otherwise promising conditions.
Rocks such as West Greenland, Nuvvuagitttttt and other countries that are older than 3.5 billion years ago have a change of change that probably prevents the preservation of fragile microfosyl forms, Stephen Mojzis, a geologist at the Hungary’s Konkoly Observatory in Budapest, told me via email.
And despite our best efforts, the melting of the Greenland ice is decided to continue.
Even in a scenario where carbon emissions fall rapidly, the sea level will increase inexplicably for thousands of years, so much of the Greenland and Antarctica ice melts, writes Bierman.
How about the ice sheet?
Greenland’s ice sheet itself covers about 80 percent of the world’s largest island, extending to 1.7 million square kilometers – about three times more than Texas size, the National Ice and Snow Data Center records. And although the merger can expose an extremely interesting sedimentary rock that may probably contain evidence of some of the earliest life on Earth, when the sheet melts, the growth of 7.4 meters that results in global sea level is expected to flood many tens of millions of homes all over the world.
What is more surprising for the Greenland’s merger?
How fragile is the ice sheet, which temperatures are not warmer than today, 1.5 C above Preindustrial, can remove the ice from at least northwest of Greenland and maybe many of the island, says Bierman.
But the question remains $ 64,000: Will Greenland potentially discover old ancient life signatures?
That we cannot say, who knows what falls there, says Mojzis.