E-Mail IMAGE: Research team leader sprays water on drill cores to see sedimentary rocks and select samples for this study. view more Credit: Andrey Bekker/UCR New research shows the permanent rise of oxygen in our atmosphere, which set the stage for life as we know it, happened 100 million years later than previously thought. A significant rise in oxygen occurred about 2.43 billion years ago, marking the start of the Great Oxidation Episode -- a pivotal moment in Earth's history. An international research team including a UC Riverside scientist analyzed rocks from South Africa formed during this event. Findings, published this week in the journal