Researchers have made an exciting discovery about our planet’s atmosphere from 1.4 billion years ago. They examined ancient halite crystals from Canada and found surprising levels of oxygen and carbon dioxide during a time once thought to be dull.
The team, led by graduate student Justin Park from Rensselaer Polytechnic Institute, analyzed the gases trapped within these crystals, offering an unprecedented glimpse into Earth’s early atmosphere. Morgan Schaller, a co-author of the study, remarked, “We’ve never been able to peer back into this era with such accuracy. These are actual samples of ancient air!”
About 1.4 billion years ago, a lake in present-day Ontario evaporated, trapping air bubbles in rock salt. These bubbles provide valuable insights into the atmosphere at that time. However, measuring gases accurately can be tricky, as their behavior changes depending on whether they’re in water or air.
The researchers overcame this challenge using an innovative method developed by Park. They discovered that the atmosphere contained ten times more carbon dioxide than it does today. This high level of CO2 helped create a climate that, surprisingly, was milder than previously thought, despite a weaker Sun at that time.
While oxygen levels were only 3.7% of what we have now, this figure is still surprisingly significant. During this period, life was mainly bacterial, but these oxygen levels might have supported more complex organisms much earlier than previously believed.
But why did animal life take so long to appear? Park suggests this moment might represent a brief spike in oxygen levels within what geologists call the “boring billion.” This term describes a long stretch of time with low oxygen, stable conditions, and minimal evolutionary change.
Interestingly, red algae emerged during this period, contributing significantly to oxygen production. Schaller noted, “What we captured might actually be a very exciting moment in the middle of the boring billion.”
Earlier estimates of CO2 levels had been lower and didn’t align with evidence that Earth did not experience major glaciation during the Mesoproterozoic era. This new data is crucial; it enhances our understanding of how life evolved and how our atmosphere has changed over billions of years.
In reflecting on the implications of these findings, it’s evident that what we called a “boring” time may have been anything but. This study provides a fascinating new perspective on Earth’s journey toward supporting diverse life forms, reminding us that science often reveals unexpected excitement in history.
For those interested in digging deeper, you can check out the original study in PNAS here and additional insights on the Mesoproterozoic era here.
