The ocean floor is vast and varied, making up more than 70% of the Earth’s surface. Scientists have long used information from sediments at the bottom of the ocean — layers of rock and microbial muck — to reconstruct the conditions in oceans of the past.
The ocean floor is vast and varied, making up more than 70% of the Earth’s surface. Scientists have long used information from sediments at the bottom of the ocean — layers of rock and microbial muck — to reconstruct the conditions in oceans of the past.
These reconstructions are important for understanding how and when oxygen became available in Earth’s atmosphere and ultimately increased to the levels that support life as we know it today.
Yet reconstructions that rely on signals from sedimentary rocks but ignore the impact of local sedimentary processes do so at their own peril, according to geoscientists including David Fike in Arts & Sciences at Washington University in St. Louis.
Their new study published Feb. 26 in Science Advances is based on analyses of a mineral called pyrite (FeS2) that is formed in the presence of bacteria. With its chemical-reduced iron (Fe) and sulphur (S), the burial of pyrite in marine sediments is one of the key controls on oxygen levels in Earth’s atmosphere and oceans.
Read more at Washington University in St. Louis
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