Category Archives: GREENLAND

Oldest fossils on Earth discovered in 3.7bn-year-old Greenland rocks

Oldest fossils on Earth discovered in 3.7bn-year-old Greenland rocks

According to recent research, tiny sediment ripples on an ancient seafloor, captured inside a 3.7 billion-year-old rock in Greenland, possibly the earliest fossils of living organisms ever found on Earth.

The research, led by Allen Nutman, head of the School of Earth and Environmental Sciences at the University of Wollongong in Australia, described the discovery of what looks like tiny waves, 0.4 to 1.5 inches (1 to 4 centimeters) high, frozen in a cross-section of the surface of an outcrop of rock in the Isua Greenstone Belt in southwestern Greenland, a formation made up of what geologists regard as the oldest rocks on the Earth’s surface.

The researchers said the ripples are the fossilized remains of cone-shaped stromatolites, layered mounds of sediment, and carbonates that build up around colonies of microbes that grow on the floor of shallow seas or lakes. 

According to the scientists, the new discovery, detailed online today in the journal Nature, supports theories that life on Earth originated during the so-called Hadean eon more than 4 billion years ago, a period of intense volcanic activity when large meteorites and icy comets frequently bombarded Earth. This was also the time when the first bodies of water formed on the planet’s surface.

The rock outcrop was found only after a series of warm summers in southwestern Greenland caused large patches of snow at the site to melt earlier than normal, revealing rocks that had not been examined by researchers since the Isua Greenstone Belt was first explored in the 1980s, Nutman told Live Science.

The stromatolites in figure a are from Greenland; those in c and d are younger stromatolites from Western Australia. Figure b shows the layers created by microbes as they formed the Greenland stromatolites (blue lines). ‘Storms’ are several overlapping stromatolites.

“Most of the rocks there are very deformed and modified by later mountain-building processes, but you do find just very tiny little areas that have survived with their original volcanic or sedimentary structures not destroyed,” Nutman said. “But this is the first one of the surviving structures where we actually have stromatolites.”

Under pressure

Remarkably, the structures were found in an outcrop of metamorphic rock that was once subject to intense underground heating and pressure, which distorted their original shapes and changed their chemical composition.

Allen Nutman (left) and Vickie Bennet (right) with a specimen of 3.7-billion-year-old stromatolites from Isua, Greenland

“The overall features, such as the shape of the stromatolites, are preserved,” Nutman said. “But some of the finer details of the very fine layering have certainly been erased — although, as we show in the paper, there are vestiges of that left.”

Sediment structures that look like stromatolites can form without the involvement of microbial life, but the researchers said they examined the chemistry and minerals in the rocks and were able to establish that they contain the fossilized remains of a colony of ancient microbes.

The 3.7-billion-year-old structures described in the new study are about 220 million years older than the fossils previously regarded as the oldest known fossils on Earth. Those 3.5-billion-year-old stromatolites, found in sedimentary rocks in Western Australia, precipitated over billions of years without metamorphic heating. Abigail Allwood, an astrobiologist at NASA’s Jet Propulsion Laboratory in Pasadena, California, whose 2006 study about the Australian fossils established their biological origin, said the new study will likely face close scrutiny. 

“These kinds of discoveries always do [cause controversy], especially when they first come out, and in this case, it’s particularly amazing because they were found in metamorphic rocks that have been significantly altered and transformed from their original characteristics,” Allwood told Live Science.

Allwood reviewed the new study by Nutman and his colleagues for a separate opinion piece published in the journal Nature. Allwood’s 2006 study is cited in the new paper, but she did not contribute directly to the latest research.

“It’s remarkable that they have found [the structures], and they’ve done a good job of analyzing what’s there — but the alteration that the rocks have seen means that there’s just a whole lot of stuff that you’d typically like to see to make such an extraordinary claim, that just isn’t preserved,” she said.

Life or nonlife?

Geochemist Balz Kamber, chair of geology and mineralogy at Trinity College Dublin in Ireland, has also studied the stromatolite fossils from Western Australia. He told Live Science that the new finds would no doubt face further scientific tests to assess the strength of the claims for a biological origin. But he added that the new structures appear to be a far better prospect for evidence of ancient life than another set of fossils reported nearly two decades ago on Greenland’s Akilia Island, which were later shown not to have a biological origin.

Kamber also said there can be little doubt that the conical structures identified in the new research are the result of sedimentation on the floor of a marine environment, regardless of whether they can be shown to have a biological origin. This means that the structures are not only evidence of standing bodies of water on the Earth’s surface 3.7 billion years ago, but also bodies of land crossed by rivers that carried chemical solutes into the ancient oceans, he said.

Both Kamber and Allwood also said the new findings have implications for the field of astrobiology and the search for evidence of past life on other planets — particularly on Mars. Kamber said these potential clues about the very early emergence of life on Earth in the Hadean period supports his own recent research, published earlier this year, about the prospects for life in the water-filled craters caused by meteorite and comet impacts on the early Earth.

“I think the enclosed impact basins at the tail end of the bombardment at 3.8 [billion] to 3.85 billion years ago would have made great places for life to emerge from,” he said.

Allwood added that there is also clear evidence that, at the time the rocks at Isua were forming 3.7 billion years ago, conditions on Mars were similar to those on early Earth.

“[T]here were similar environments in bodies of water standing at the surface of Mars, offering a similar kind of environment to the ones that hosted the early evidence of life on Earth, at Isua and younger,” she said.

Until now, there had been a gap between the start of the fossil record on Earth and the youngest areas on Mars, where there was good evidence for standing bodies of water in the past.

“And you had to imagine that life could have arisen there before they dried up — but now at least we may have one example in the fossil record showing us that life can arise that quickly,” Allwood said.

Surprise: Ancient Inuit Mummy Scans Reveal Possible Heart Disease

Surprise: Ancient Inuit Mummy Scans Reveal Possible Heart Disease

While omega-3 diets are rich in fish, The 500-year-old Inuit mummies discovered in Greenland tell scientists of their suffering from clogged arteries that they are intended to protect from plaque build-up in the arteries.

Atherosclerosis is a condition in which the walls of arteries become blocked with fat and calcium and it is known this condition was suffered at least 6,000 years ago but none of the humans remains studied thus far was known to eat a marine-based diet. Now, however, researchers have studied four Inuit mummies and found evidence of arterial clogging.

Atherosclerosis is the build-up of plaques of fat, cholesterol, and calcium in one’s arteries and the disease is a leading cause of death in modern wealthy countries, thought to be caused by poor dietary control.

However, a new paper published in the journal  JAMA Network Open challenges this commonly held notion after scientists studied the remains of four 16th-century Inuit hunters found in Greenland who also suffered from clogged-up arteries, despite their diets being rich in omega-3 fatty acids.

Landscape from Greenland with Inuit woman looking at the sea by Emanuel Petersen.

While the condition is often seen as resulting from modern lifestyles and diets, evidence of atherosclerosis has been found in human remains dating back as far as around 4,000 BC, but none of those tested bodies had eaten a diet rich in omega-3 fatty acids.

Four incredibly well-preserved 16th-century Inuit mummies who ate omega 3-rich diets were tested with a view to seeing if the fatty acid improved arterial health, and the results suggest diets rich in omega-3 may not assure resistance to arterial plaque build-up, leading to the researchers considering that other factors might be at play.

According to a report in The Daily Mail, a team of scientists led by cardiologist L. Samuel Wann of Ascension Healthcare in Milwaukee studied the Inuit mummies taken from the collections of the Peabody Museum of Archaeology and Ethnology in Cambridge. Originally discovered on the island of Uunartaq, off the coast of Greenland in 1929 and dated to the 1500s, the mummies include two men and two women between the ages of 18–30.

Living in stone huts supported with whale bones and seal skins, the kayak hunters would have used wooden spears, bows, and arrows to kill fish, marine mammals, birds, and caribou, and with their greatly marine-based diets, their veins would have surged with omega-3 fatty acids.

But CT scans of the mummies’ insides were analyzed by Dr. Wann and his team of four cardiologists and two radiologists which showed ‘calcified atheroma’ which is an accumulation of fatty plaque material in the arteries, similar to modern humans with atherosclerosis.

Computed Tomography Images Showing Calcified Atherosclerotic Plaques. Arrows indicate calcified atherosclerotic plaques.

The condition, and the diseases it can cause, is the single biggest cause of death in the developed world and is responsible for one in three fatalities.

Over time, blood vessels harden and narrow, which restricts the flow of blood around the body, and when these plaque deposits rupture they form a blood clot that can further block the flow of oxygenated blood which can result in a stroke or heart attack.

According to the Heart Research Institute atherosclerosis often begins in childhood and worsens with age damaging the endothelium, a thin layer that keeps the inside of our arteries smooth.

Once damaged, ‘bad’ cholesterol accumulates in the artery wall the body sends immune cells to clean up this cholesterol, which can then get stuck in the damaged site and this is what builds up over time leading to blockages.

This new study presents evidence for the “presence of calcified plaques in the mummified remains of 3 young Inuit individuals living 500 years ago,” the researchers wrote in their paper, and that omega 3 rich diets might not guarantee against plaque buildup as currently believed.

However, according to Discover Magazine, the researchers urge caution for other factors that might be at play, like environmental smoke produced by the use of indoor fires.