How did Earth become an oxygen-rich planet? The mystery can be solved in Gabon
UU researcher part of a strong international research group from 17 countries that has been awarded 1.6 million dollars for an extensive drilling program in the West African country of Gabon.
A new drilling project involving scientists from 17 countries has received $1.6 million (approximately 16 5000 000 SEK) to find out how oxygen made the Earth habitable.
Anna Neubeck, researcher at the Department of Earth Sciences at Uppsala University.
It has long been a mystery how oxygen levels rose in the atmosphere and made the world habitable. An international team of researchers from 17 countries will now drill deep into the bedrock of Gabon, in West Africa, to understand how the Earth became an oxygen-rich planet over two billion years ago. The project has been awarded USD 1.6 million (around 16 5000 000 SEK) from the International Continental Scientific Drilling Programme (ICDP) and the universities and research councils of the 17 participating countries will fund the remaining costs of an estimated USD 3.2 million (SEK 32 687 936).
Researchers will drill 11 holes and take four kilometres of rock cores. The samples will help scientists understand important changes in Earth's history, such as how oxygen in the atmosphere increased and how life on Earth evolved. The project will also provide more knowledge about important elements such as phosphorus, black shale, nickel and manganese, which are used in steel production.
Anna Neubeck, geochemist and researcher at the Department of Earth Sciences, is the only Swedish researcher participating from Sweden.
How can drill cores reveal something about how the Earth was oxygenated?
- Drill cores can provide important information about how the Earth was oxygenated because they contain preserved layers of sediments and rocks from different geological time periods. These layers act as a timeline of Earth's history and can contain chemical and mineralogical traces that reveal changes in the composition of the atmosphere, including oxygen levels.
You are drilling four kilometres into the rock. What ages do the cores come from and what was the soil like then?
- Drill cores from a borehole as deep as the one in Gabon mostly come from the Palaeoproterozoic, a period that lasted from around 2.5 to 1.6 billion years ago. The Francevillian Supergroup, where these layers are located, is particularly known to be around 2.1 billion years old. During this time, the so-called Great Oxidation Event (GOE) occurred, which was the first major increase in oxygen in the Earth's atmosphere. This radically changed the Earth's chemistry and environmental conditions. Oxygen production was driven by cyanobacteria carrying out photosynthesis and began to greatly increase atmospheric oxygen levels. The Earth also underwent one of the first major ice ages, called the Huronian glaciation. This ice age is thought to have been the result of decreasing methane in the atmosphere and increasing oxygen, leading to a global cooling. Life on Earth during this time was mainly microbial. Cyanobacteria, which produced oxygen through photosynthesis, were dominant. In the Francevillian Supergroup, fossilised traces of multicellular life have been found that are believed to be among the oldest known examples of eukaryotes, showing that more complex life forms began to evolve during this period. The Earth's crust was dynamic, with extensive volcanism and rock formation. The supercontinent Nuna is thought to have begun to form during this period, affecting the climate and environment globally.
A new geological archive opens
One of the initiators of the project is PI Aivo Lepland, a researcher at the Geological Survey of Norway (NGU).
- There are still gaps in our knowledge before we can better understand how the Earth's surface environments evolved between 2.5 and 2 billion years ago. This includes questions about what happened when the Earth underwent a complete transformation into an oxygen-rich planet’. The cores will be collected around the town of Franceville in Gabon. This is where we find the best-preserved sedimentary rocks formed during this crucial period in Earth's history. The sediments have undergone minimal deformation and metamorphism. Here we will open a new geological archive,’ explains PI Aivo Lepland.
For more information contact:
Anna Neubeck, researcher in palaeobiology.
Phone: 018-471 25 62
E-mail: anna.neubeck@geo.uu.se
Read more here: https://www.icdp-online.org/projects/by-continent/africa/goe-deep-gabon/