![green epidote crystal val malenco valtellina italy green epidote crystal val malenco valtellina italy](https://www.mineralfossil.com/wp-content/gallery/macro/thumbs/thumbs_epidoto-sissone.jpg)
![vesuvianite val malenco valtellina italy vesuvianite val malenco valtellina italy](https://www.mineralfossil.com/wp-content/gallery/macro/thumbs/thumbs_vesuviana-val-lanterna-3.jpg)
![vesuvianite val malenco valtellina italy vesuvianite val malenco valtellina italy](https://www.mineralfossil.com/wp-content/gallery/macro/thumbs/thumbs_vesuviana-val-lanterna.jpg)
![geode calcedonio brasil (2).JPG geode calcedonio brasil (2).JPG](https://www.mineralfossil.com/wp-content/gallery/south-america/thumbs/thumbs_geode-calcedonio-brasil-2.jpg)
![geode calcedonio brasil.JPG geode calcedonio brasil.JPG](https://www.mineralfossil.com/wp-content/gallery/south-america/thumbs/thumbs_geode-calcedonio-brasil.jpg)
![magnetite brasil.JPG magnetite brasil.JPG](https://www.mineralfossil.com/wp-content/gallery/south-america/thumbs/thumbs_magnetite-brasil.jpg)
![quartz japanese geminate brasil.JPG quartz japanese geminate brasil.JPG](https://www.mineralfossil.com/wp-content/gallery/south-america/thumbs/thumbs_quartz-japanese-geminate-brasil.jpg)
![azurite morocco.JPG azurite morocco.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_azurite-morocco-2.jpg)
![calcite morocco.JPG calcite morocco.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_calcite-morocco.jpg)
![carollite.JPG carollite.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_carollite.jpg)
![celestine madagascar.JPG celestine madagascar.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_celestine-madagascar.jpg)
![cerussite barite morocco.JPG cerussite barite morocco.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_cerussite-barite-morocco.jpg)
![malachite Democratic Republic of the Congo (formerly Zaire) Lukuni Mine in Katanga Province.JPG malachite Democratic Republic of the Congo (formerly Zaire) Lukuni Mine in Katanga Province.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_malachite-democratic-republic-of-the-congo-formerly-zaire-lukuni-mine-in-katanga-province.jpg)
![vanadinite morocco.JPG vanadinite morocco.JPG](https://www.mineralfossil.com/wp-content/gallery/africa/thumbs/thumbs_vanadinite-morocco.jpg)
![almandine gilgit pakistan.JPG almandine gilgit pakistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_almandine-gilgit-pakistan.jpg)
![fluorite china.JPG fluorite china.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_fluorite-china.jpg)
![fluorite india.JPG fluorite india.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_fluorite-india.jpg)
![hematite rose on quartz china.JPG hematite rose on quartz china.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_hematite-rose-on-quartz-china.jpg)
![lapislazzuli afganistan.JPG lapislazzuli afganistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_lapislazzuli-afganistan.jpg)
![quartz epidote china.JPG quartz epidote china.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_quartz-epidote-china.jpg)
![topaz pakistan.JPG topaz pakistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_topaz-pakistan.jpg)
![topaz quartz pakistan.JPG topaz quartz pakistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_topaz-quartz-pakistan.jpg)
![tormaline pakistan.JPG tormaline pakistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_tormaline-pakistan.jpg)
![zircone pakistan.JPG zircone pakistan.JPG](https://www.mineralfossil.com/wp-content/gallery/asia/thumbs/thumbs_zircone-pakistan.jpg)
![analcime sardegna,Italy.JPG analcime sardegna,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_analcime-sardegnaitaly.jpg)
![andradite garnet isola d'elba,Italy.JPG andradite garnet isola d'elba,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_andradite-garnet-isola-delbaitaly.jpg)
![aragonite spagna.JPG aragonite spagna.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_aragonite-spain.jpg)
![calcite italy.JPG calcite italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_calcite-italy.jpg)
![calcite valtellina,Italy (2).JPG calcite valtellina,Italy (2).JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_calcite-valtellinaitaly-2.jpg)
![calcite valtellina,Italy (4).JPG calcite valtellina,Italy (4).JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_calcite-valtellinaitaly-4.jpg)
![calcite valtellina,Italy.JPG calcite valtellina,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_calcite-valtellinaitaly.jpg)
![epidote valmalenco,Italy.JPG epidote valmalenco,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_epidote-valmalencoitaly.jpg)
![grossularia liguria,Italy.JPG grossularia liguria,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_grossularia-liguriaitaly.jpg)
![hessonite adamello,Italy.JPG hessonite adamello,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_hessonite-adamelloitaly.jpg)
![orthoclase quartz elba island,Italy.JPG orthoclase quartz elba island,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_orthoclase-quartz-elba-islanditaly.jpg)
![pyromorphite sardegna,Italy.JPG pyromorphite sardegna,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_pyromorphite-sardegnaitaly.jpg)
![quartz emilia romagna,Italy.JPG quartz emilia romagna,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_quartz-emilia-romagnaitaly.jpg)
![quartz formazza,Italy.JPG quartz formazza,Italy.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_quartz-formazzaitaly.jpg)
![quartz rodocrosite romania.JPG quartz rodocrosite romania.JPG](https://www.mineralfossil.com/wp-content/gallery/europe/thumbs/thumbs_quartz-rodocrosite-romania.jpg)
![apatite messico.JPG apatite messico.JPG](https://www.mineralfossil.com/wp-content/gallery/north-america/thumbs/thumbs_apatite-messico.jpg)
![]() |
Photo credit: Mableen/iStock |
Earth’s oxygen-rich atmosphere emerged in whiffs from a kind of blue-green algae in shallow oceans around 2.5 billion years ago, according to new research from Canadian and US scientists.
These whiffs of oxygen likely happened in the following 100 million years, changing the levels of oxygen in Earth’s atmosphere until enough accumulated to create a permanently oxygenated atmosphere around 2.4 billion years ago – a transition widely known as the Great Oxidation Event.
“The onset of Earth’s surface oxygenation was likely a complex process characterized by multiple whiffs of oxygen until a tipping point was crossed,” said Brian Kendall, a professor of Earth and Environmental Sciences at the University of Waterloo. “Until now, we haven’t been able to tell whether oxygen concentrations 2.5 billion years ago were stable or not. These new data provide a much more conclusive answer to that question.”
The findings are presented in a paper published this month in Science Advances from researchers at Waterloo, University of Alberta, Arizona State University, University of California Riverside, and Georgia Institute of Technology. The team presents new isotopic data showing that a burst of oxygen production by photosynthetic cyanobacteria temporarily increased oxygen concentrations in Earth’s atmosphere.
“One of the questions we ask is: ‘did the evolution of photosynthesis lead directly to an oxygen-rich atmosphere? Or did the transition to today’s world happen in fits-and-starts?” said Professor Ariel Anbar of Arizona State University. “How and why Earth developed an oxygenated atmosphere is one of the most profound puzzles in understanding the history of our planet.”
The new data supports a hypothesis proposed by Anbar and his team in 2007. In Western Australia, they found preliminary evidence of these oxygen whiffs in black shales deposited on the seafloor of an ancient ocean.
The black shales contained high concentrations of the elements molybdenum and rhenium, long before the Great Oxidation Event.
These elements are found in land-based sulphide minerals, which are particularly sensitive to the presence of atmospheric oxygen. Once these minerals react with oxygen, the molybdenum and rhenium are released into rivers and eventually end up deposited on the sea floor.
In the new paper, researchers analyzed the same black shales for the relative abundance of an additional element: osmium. Like molybdenum and rhenium, osmium is also present in continental sulfide minerals. The ratio of two osmium isotopes – 187Os to 188Os – can tell us if the source of osmium was continental sulfide minerals or underwater volcanoes in the deep ocean.
The osmium isotope evidence found in black shales correlates with higher continental weathering as a result of oxygen in the atmosphere. By comparison, slightly younger deposits with lower molybdenum and rhenium concentrations had osmium isotope evidence for less continental input, indicating the oxygen in the atmosphere had disappeared.
Journal reference: Science Advances Provided by: University of Waterloo