Earth's ancient diamonds reveal a prepared environment for life's rapid expansion dated back approximately 2.7 billion years
The distribution of essential volatile elements between the Earth's mantle and the atmosphere has remained relatively stable throughout the majority of Earth's life, according to a recent study. This groundbreaking research, led by Dr Maureen L. T. G. E. L. Smith, provides crucial insights into the volatile composition of our planet and its implications for the origin and development of life.
The study, presented at the 2021 Goldschmidt Conference held virtually from 4-9 July, and to be continued at the 2022 conference in Hawaii, focused on the volatile composition of the Earth's mantle. The findings suggest that this composition has changed little over the last 2.7 billion years.
The mantle, which comprises around 84% of the Earth's volume, has probably experienced little change in the proportion of volatiles. Ancient diamonds were used as a time capsule to examine the conditions deep inside the Earth's mantle in the distant past. The team measured the isotopes of Helium, Neon, and Argon in these diamonds and found similar proportions to those found in the upper mantle today.
Dr Suzette Timmerman of the University of Alberta commented that the study of ancient diamonds provides important clues into the volatile composition during the Neoarchean period. She also stated that the upper mantle appears to have been degassed more than 2.7 billion years ago.
Volatiles, such as hydrogen, nitrogen, neon, and carbon-bearing species, are necessary for life and can be readily vaporized due to heat or pressure changes. The research suggests that the volatile-rich environment we see around us today is not a recent development, indicating that it provided the right conditions for life to develop at least 2.7 billion years ago.
The conditions suitable for life were present at least 2.7 billion years ago, but the diamonds used in the study may be much older, suggesting that these conditions were set well before our 2.7 billion year threshold. This finding underscores the importance of the study of volatile substances on Earth in understanding when the conditions were suitable for the origin and development of life.
Earth, like Venus, is rich in volatiles, but Mars and the Moon lost most of theirs into space. A planet rich in volatiles has a better chance of sustaining life, making the stability of these elements in the Earth's mantle and atmosphere a key factor in the planet's ability to support life.
The Goldschmidt Conference, the World's main geochemistry conference, is hosted alternately by the European Association of Geochemistry (Europe) and the Geochemical Society (USA). The conference provides a platform for scientists to share their latest findings and advance our understanding of the Earth and its processes.
The basic chemical composition of the Earth's atmosphere suitable for life's diversity was established 2.7 billion years ago, according to the study. This finding not only sheds light on the history of our planet but also offers insights into the potential habitability of other planets in the universe.
Diamonds, being comparatively indestructible, are ideal time capsules for studying the past. The study of ancient diamonds provides a unique window into the Earth's history, offering valuable insights into the volatile composition and the conditions suitable for life in the distant past.
