Between 2.2 and 2.4 billion years ago, big masses of land rose quickly from the depths of the sea, causing big changes on our planet. A new study published on May 24th in the journal Nature suggests that it was these changes that caused Earth’s first snowfall 2.4 billion years ago.
The study shows the findings of Ilya Bindeman, a geologist and professor in the department of Earth Sciences at the University of Oregon and a team of researchers studying shale from every continent. Shale, the most abundant from of sedimentary rock, is formed from the weathering of crust. This weathered crust can tell researchers a lot about exposure to light, air, and precipitation and provide a continuous record of such exposure. The research team detected a shift in the chemical makeup of the shale around the 2.4 billion-year point. This shift coincides with the early land collisions that formed some of Earth’s first high mountain ranges.
Shale. Image: rigzone
According to Bindeman, once the large continents emerged from the sea, more light would have been reflected back into space, triggering runaway glaciation and a change in flow of atmospheric gases and other processes, leading to Earth’s first snow.