Update: 06 Jul 2021 16:37 STI
Paris [France], July 6 (ANI): A unique study of ancient diamonds has shown that the basic chemical composition of Earth’s atmosphere that makes it conducive to the explosion of the diversity of life was established at least 2 years ago, 7 billion years.
The volatile gases preserved in diamonds found in ancient rocks were present in proportions similar to those found in the present mantle, indicating that there was no fundamental change in the proportions of volatiles in the atmosphere at over the last billion years.
This shows that one of the basic conditions necessary for sustaining life, the presence of life-giving elements in sufficient quantity, arose soon after the formation of the Earth and has remained fairly constant ever since.
Presenting the work at the Goldschmidt Geochemistry Conference, Principal Investigator Dr Michael Broadly said: “The proportion and composition of volatiles in the atmosphere mirror those found in the mantle, and we have no evidence a significant change since these diamonds were formed 2.7 billion years ago “.
Volatiles, such as hydrogen, nitrogen, neon, and carbonaceous species, are light chemical elements and compounds, which can be easily vaporized due to heat or pressure changes. They are necessary for life, especially carbon and nitrogen.
Not all planets are rich in birds; The Earth is rich in birds, as is Venus, but Mars and the Moon have lost most of their birds in space. In general, a planet rich in volatiles has a better chance of sustaining life, which is why much of the research for life on planets surrounding distant stars (exoplanets) has focused on finding volatiles.
On Earth, volatile substances mainly bubble from the interior of the planet and are brought to the surface by volcanic eruptions such as. Knowing when the birds first arrived in Earth’s atmosphere is essential to understanding when conditions on Earth were right for life to originate and develop, but until now there was no way to understand these conditions. in the distant past.
Today, French and Canadian researchers have used ancient diamonds as a time capsule to examine conditions deep inside the Earth’s mantle in the distant past. Studies of the gases trapped in these diamonds show that the volatile composition of the mantle has changed little over the past 2.7 billion years.
Principal investigator Michael Broadley (University of Lorraine, France) said: “Studying the composition of the Earth’s modern mantle is relatively straightforward. On average, the mantle layer begins about 30 km below the Earth’s surface, so we can collect samples that are released from volcanoes. and study the fluids and gases trapped inside. “
“However, the constant churning of the earth’s crust via plate tectonics means that the older samples have mostly been destroyed. Diamonds are however relatively indestructible, they are ideal time capsules,” added Broadley.
“We have successfully studied diamonds trapped in highly preserved 2.7 billion year old rocks from Wawa on Lake Superior in Canada. This means that diamonds are at least as old as the rocks they are in – probably older. It’s hard to date diamonds, so this gave us a lucky chance to be sure of the minimum age, ”said Broadley.
Broadley added: “These diamonds are incredibly rare and don’t look like the beautiful gemstones we think of when we think of diamonds. We heated them to over 2000 ° C to turn them into graphite, which then released tiny amounts. of gas for the measurement. “
The team measured the isotopes of helium, neon and argon and found that they were present in proportions similar to those found in the upper mantle today.
This means that there has probably been little change in the proportion of volatiles in general, and that the distribution of essential volatiles between the mantle and the atmosphere has likely remained fairly stable for most of life on Earth. The mantle is the part between the earth’s crust and the core, it comprises about 84 percent of the Earth’s volume.
Dr Broadley continued: “It was a surprising result. This means that the bird-rich environment that we see around us today is not a recent development, thus providing the right conditions for life to thrive. billions of years ago, but the diamonds we use may be much older, so it is likely that these conditions were established long before our threshold of 2.7 billion years. “(ANI)