The first rise of mountain ranges 2.5 billion years ago changed planet Earth
A sudden increase in landmasses and the altitude of mountains around 2.5 billion years ago triggered dramatic changes in climate and life on planet Earth (photo: Basil Greber)
“Rapid emergence of subaerial landmasses and onset of a modern hydrologic cycle 2.5 billion years ago”, Bindeman et. al., Nature, May 24, 2018. doi: 10.1038/s41586-018-0131-1
Postdoctoral researcher Dr. Nicolas Greber participated in a study published in the May 24 issue of the journal Nature which shows that ~2.5 billion years ago the amount of landmasses and the height of mountain ranges suddenly increased -- triggering dramatic changes in climate and life on Earth.
The research team used a specific chemical signature ‑‑ the isotopic composition of oxygen ‑‑ in sedimentary rocks to study under what condition rain and river water interacted with Earth’s continents. The results show that rock-water interaction before 2.5 billion years ago occurred predominantly at high temperature and low altitude, similar to modern coastal environments. In contrast, after 2.5 billion years, the chemical signatures point to a more diverse landscape, with rain and river water interacting with the surface at higher altitudes and lower temperatures, as observed nowadays for example in the Swiss Alps.
This change towards more land and higher mountains 2.5 billion years ago coincides with a crucial turning point in Earth’s history, when oxygen started for the first time to be an important constituent of the atmosphere, making it possible for multi-celled organisms to evolve. The authors argue that the accumulation of oxygen in the atmosphere is a direct result of the climatic and environmental changes triggered by the emergence of large landmasses and mountains.
May 24, 2018