Earth’s first snow may have fallen after a lot of land rose swiftly from the sea and set off dramatic changes on Earth 2.4 billion years ago, says UO geologist Ilya Bindeman.
Earth’s first snow may have fallen after a lot of land rose swiftly from the sea and set off dramatic changes on Earth 2.4 billion years ago, says UO geologist Ilya Bindeman.
That notion comes from research done on shale in Bindeman’s Stable Isotope Laboratory. Shale is the world’s most abundant sedimentary rock, and the lab used samples drawn from every continent.
Scientists looked at ratios of three common oxygen isotopes, or chemical signatures. They found archival-quality evidence from as far back as 3.5 billion years ago showing traces of rainwater that caused weathering of land.
Shale rocks are formed by the weathering of crust. Bindeman, a professor in the Department of Earth Sciences, initially began collecting shale samples while doing petroleum-related research.
"They tell you a lot about the exposure to air and light and precipitation,” he said. “The process of forming shale captures organic products and eventually helps to generate oil. Shales provide us with a continuous record of weathering."
Read more at University of Oregon
Image: Before and After: How Earth's land elevations may have looked before and after the Great Oxygenation Event (Courtesy of Ilya Bindeman)
