Rock Record Illuminates Oxygen History

Dating the rise of atmospheric oxygen

Several lines of geological and geochemical evidence indicate that the level of atmospheric oxygen was extremely low before 2.45 billion years (Gyr) ago, and that it had reached considerable levels by 2.22 Gyr ago. Here we present evidence that the rise of atmospheric oxygen had occurred by 2.32 Gyr ago. We found that syngenetic pyrite is present in organic-rich shales of the 2.32-Gyr-old Rooihoogte and Timeball Hill formations, South Africa. Th…

Rock record illuminates oxygen history

A new study reveals that the aerobic nitrogen cycle in the ocean may have occurred about 100 million years before oxygen began to significantly accumulate in the atmosphere, based on nitrogen isotope analysis from ancient South African rock cores. These findings not only refine the timeline of Earth's oxygenation but also highlight a critical evolutionary shift, where life began adapting to oxygen-rich conditions -- paving the way for the emerge…

Rock Record Illuminates Earth's Oxygen History - Astrobiology

Several key moments in Earth’s history help us humans answer the question, “How did we get here?” These moments also shed light on the question, “Where are we going”? – offering scientists deeper insight into how organisms adapt to physical and chemical changes in their environment. Among them is an extended evolutionary occurrence over 2 […] The post Rock Record Illuminates Earth’s Oxygen History appeared first on Astrobiology.

Rock record illuminates oxygen history - Conservative Angle

A new study reveals that the aerobic nitrogen cycle in the ocean may have occurred about 100 million years before oxygen began to significantly accumulate in the atmosphere, based on nitrogen isotope analysis from ancient South African rock cores. These findings not only refine the timeline of Earth's oxygenation but also highlight a critical evolutionary shift, where life began adapting to oxygen-rich conditions -- paving the way for the emerge…

Great Oxidation Event and Snowball Earth

The atmosphere of early Earth contained little molecular oxygen. A significant increase in oxygen occurred ca. 2.4–2.0 billion years ago in what is called the Great Oxidation Event (GOE). A large positive excursion in carbon isotopic composition in sedimentary...