Tiny Bubbles of Ancient Trapped Water Explains Earth's First Ice Age

Tiny bubbles of water discovered in quartz grains in Australia may provide clues behind what caused the Earth's first ice age, according to a news release.

The study, published in the journal Nature, examined the level of ancient atmospheric argon gas isotopes that were dissolved in the bubbles, and noticed that the levels varied from those that are present in the air we breathe today.

The Anglo-French study explains why Earth never underwent its first ice age until 2.5 billion years ago, even when the sun's rays were weaker during the early years of planet formation. According to the researchers, these water samples came from the Pilbara region, which is located in north-west Australia. At the time of the eruption of pillow basalt lava, the waters were heated mostly in a lake or lagoon environment.

"Evidence from the geological record indicates that the first major glaciations on Earth occurred about 2.5 billion years ago, and yet the energy of the Sun was 20 per cent weaker prior to, and during, this period, so all water on Earth should already have been frozen. This is something that has baffled scientists for years but our findings provide a possible explanation," said author Dr. Ray Burgess, from the University of Manchester's School of Earth, Atmospheric and Environmental Sciences, in a press statement.  

The researchers noticed that the ratio of two argon isotopes, 40Ar and 36Ar, were much lower when compared to the present day. With the help of the argon isotope ratio, the researchers analyzed how continents have evolved over geological time and noticed that the volume of the continental crust 3.5 billion years ago was already well-created.

The study researchers suspect that the reason why the Earth did not freeze is because of the increasing levels of carbon dioxide, a greenhouse gas in the early atmosphere that helped in retaining heat from the Sun.

Burgess explains that an estimation of the Earth's evolution in the past is very fragile, with just fragments of extremely weathered rocks present from that time period, and no direct evidence.

The study was published in the journal PLOS ONE.