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Earth's Oxygen Came From an Unexpectedly Deep And Hot Source, Study Suggests

maximus otter

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The amount of oxygen in the Earth's atmosphere makes it a habitable planet.

Twenty-one percent of the atmosphere consists of this life-giving element. But in the deep past – as far back as the Neoarchean era 2.8 to 2.5 billion years ago – this oxygen was almost absent.

So, how did Earth's atmosphere become oxygenated?

Our research, published in Nature Geoscience, adds a tantalizing new possibility: that at least some of the Earth's early oxygen came from a tectonic source via the movement and destruction of the Earth's crust.

We found that the magma sulfur content, which was initially around zero, increased to 2,000 parts per million around 2705 million years. This indicated the magmas had become more sulfur-rich.

Additionally, the predominance of S6+ – a type of sulfur ion – in the apatite suggested that the sulfur was from an oxidized source, matching the data from the host zircon crystals.

These new findings indicate that oxidized magmas did form in the Neoarchean era 2.7 billion years ago. The data show that the lack of dissolved oxygen in the Archean ocean reservoirs did not prevent the formation of sulfur-rich, oxidized magmas in the subduction zones.

The oxygen in these magmas must have come from another source and was ultimately released into the atmosphere during volcanic eruptions.

https://www.sciencealert.com/earths...expectedly-deep-and-hot-source-study-suggests

maximus otter
 
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